First Interstate BancSystem (FIBK) 10-K24 Feb 232022 FY Annual reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2022	Jan. 31, 2023	Jun. 30, 2022
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-34653
Entity Registrant Name	FIRST INTERSTATE BANCSYSTEM, INC.
Entity Central Index Key	0000860413
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Incorporation, State or Country Code	MT
Entity Tax Identification Number	81-0331430
Entity Address, Address Line One	401 North 31st Street
Entity Address, City or Town	Billings,
Entity Address, State or Province	MT
Entity Address, Postal Zip Code	59101
City Area Code	406
Local Phone Number	255-5311
Title of 12(b) Security	Class A common stock, no par value
Trading Symbol	FIBK
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 3,400,000,000
Entity Common Stock, Shares Outstanding		104,441,157
Document Period End Date	Dec. 31, 2022

Audit Information

Audit Information	12 Months Ended
Audit Information	Dec. 31, 2022
Auditor Information [Abstract]
Auditor Name	RSM US LLP
Auditor Location	Des Moines, Iowa
Auditor Firm ID	49

Cover

Cover	12 Months Ended
Cover	Dec. 31, 2022
Cover [Abstract]
Documents Incorporated by Reference	The registrant intends to file a definitive Proxy Statement for the Annual Meeting of Shareholders scheduled to be held May 24, 2023. The information required by Part III of this Form 10-K is incorporated by reference to such Proxy Statement.

Earnings per Common Share - Tab

Earnings per Common Share - Tables	12 Months Ended
Earnings per Common Share - Tables	Dec. 31, 2022
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings per Share	The following table sets forth the computation of basic and diluted earnings per common share: Year Ended December 31, 2022 2021 2020 Net income, basic and diluted $ 202.2 $ 192.1 $ 161.2 Weighted average common shares outstanding for basic earnings per share computation 103,274,070 61,650,312 63,611,891 Dilutive effects of stock-based compensation 66,929 91,516 117,579 Weighted average common shares outstanding for diluted earnings per common share computation 103,340,999 61,741,828 63,729,470 Basic earnings per common share $ 1.96 $ 3.12 $ 2.53 Diluted earnings per common share 1.96 3.11 2.53

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Assets
Cash and due from banks	$ 349.2	$ 168.6
Federal funds sold	521.2	2,176.1
Interest bearing deposits in banks	0.1	0.1
Total cash and cash equivalents	870.5	2,344.8
Investment securities:
Available-for-sale	6,946.1	4,820.5
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	3,451.8	1,687.6
Investments, Total	10,397.9	6,508.1
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	198.6	53.8
Loans held for sale	79.9	30.1
Loans and Leases Receivable, Net of Deferred Income	18,099.2	9,331.7
Less allowance for loan losses	220.1	122.3
Net loans	17,879.1	9,209.4
Goodwill	1,100.9	621.6
Company-owned life insurance	497.9	301.5
Premises and equipment, net of accumulated depreciation	444.7	299.6
Other intangibles, net of accumulated amortization	97	41.3
Accrued interest receivable	118.3	47.4
Mortgage servicing rights, net of accumulated amortization and impairment reserve	31.1	28.2
Other real estate owned	12.7	2
Deferred Income Tax Assets, Net	210.5	0
Other assets	348.7	184.1
Total assets	32,287.8	19,671.9
Deposits:
Non-interest bearing	7,560	5,568.3
Interest bearing	17,513.6	10,701.3
Total deposits	25,073.6	16,269.6
Securities sold under repurchase agreements	1,052.9	1,051.1
Accounts payable and accrued expenses	445.9	148.4
Accrued interest payable	14.5	3.7
Deferred tax liability, net	0	9.3
Long-term debt	120.8	112.4
Other borrowings	2,327	0
Allowance for credit losses on off-balance sheet credit exposures	16.2	3.8
Subordinated debentures held by subsidiary trusts	163.1	87
Total liabilities	$ 29,214	$ 17,685.3
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Preferred Stock, No Par Value	$ 0	$ 0
Preferred Stock, Shares Authorized	100,000	100,000
Common Stock, Shares, Issued	104,442,023	62,200,456
Common stock, shares, outstanding	104,442,023	62,200,456
Common Stock, Par or Stated Value Per Share	$ 0	$ 0
Stockholders’ equity:
Nonvoting noncumulative preferred stock without par value; authorized 100,000 shares; no shares issued or outstanding as of December 31, 2019 and 2018	$ 0	$ 0
Common stock	2,478.2	945
Retained earnings	1,072.7	1,052.6
Accumulated other comprehensive income (loss), net	(477.1)	(11)
Total stockholders’ equity	3,073.8	1,986.6
Total liabilities and stockholders’ equity	$ 32,287.8	$ 19,671.9
Common stock, shares authorized	250,000,000	100,000,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Assets:
Held-to-maturity investment securities, estimated fair value	$ 3,052.2	$ 1,667.5

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Millions	12 Months Ended
Consolidated Statements of Income - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Interest income:
Interest and fees on loans	$ 790.2	$ 430.2	$ 453.4
Interest and dividends on investment securities:
Taxable	212.4	67.1	63.4
Exempt from federal taxes	5.4	5.6	2.7
Interest on deposits in banks	8.7	2.6	4.1
Total interest income	1,021.5	506.5	524.4
Interest expense:
Interest on deposits	48.3	8.1	18.1
Interest on securities sold under repurchase agreements	2.5	0.4	0.9
Interest on other borrowed funds	15.3	0	0
Interest on long-term debt	6	6	4.6
Interest on subordinated debentures held by subsidiary trusts	6.8	2.8	3
Total interest expense	78.9	17.3	26.6
Net interest income	942.6	489.2	497.8
Provision for (reversal of) credit losses	82.7	(14.6)	56.9
Net interest income after provision for (reversal of) credit losses	859.9	503.8	440.9
Payment Services Revenues	74.1	45.1	41.1
Non-interest income:
Revenue from Contract with Customer, Excluding Assessed Tax	15.5	7.9	12.1
Fees and Commissions, Mortgage Banking and Servicing	18.7	40.8	47.3
Investment Banking, Advisory, Brokerage, and Underwriting Fees and Commissions	34.3	26.3	23.8
Service Charges on Deposit Accounts	24.6	16.5	17.6
Investment securities (losses) gains, net	(24.4)	1.1	0.3
Other income	20.4	11.8	13.7
Total non-interest income	163.2	149.5	155.9
Non-interest expense:
Salaries and wages	282.1	164.9	173.7
Employee benefits	77.5	55.8	49.4
Information Technology and Data Processing	54.3	32.8	32.8
Occupancy, Net	44	28.7	28.5
Equipment Expense	23.4	17.6	15.5
OREO expense, net of income	2.3	(0.2)	(0.5)
Professional fees	19.1	12.1	10.9
FDIC insurance premiums	14	6.6	5.9
Other intangibles amortization	15.9	9.9	10.9
Other expenses	114.5	65.7	60.4
Acquisition related expenses	118.9	11.6	0
Total non-interest expense	766	405.5	387.5
Income before income tax	257.1	247.8	209.3
Provision for income tax	54.9	55.7	48.1
Net income	$ 202.2	$ 192.1	$ 161.2
Basic earnings per common share (in dollars per share)	$ 1.96	$ 3.12	$ 2.53
Diluted earnings per common share (in dollars per share)	$ 1.96	$ 3.11	$ 2.53
Other Interest and Dividend Income	$ 4.8	$ 1	$ 0.8

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 202.2	$ 192.1	$ 161.2
Investment securities available-for-sale:
Change in net unrealized (losses) gains during the period	(613.1)	(113.7)	61.8
Reclassification adjustment for net losses (gains) included in income	24.4	(1.1)	(0.3)
Reclassification adjustment for securities transferred from held-to-maturity to available-for-sale	0.2	0	0
OCI, Debt Securities, Available-for-Sale, Transfer to Held-to-Maturity, Adjustment from AOCI for Amortization of Gain (Loss), before Tax	26.1	(20.2)	0
Change in net unrealized (gain) loss on derivatives	(6.7)	4.2	0.2
Defined benefit post-retirement benefit plans:
Change in net actuarial loss	0	0	(0.5)
Other comprehensive (loss) income, before tax	(621.3)	(90.4)	61.2
Deferred tax benefit (expense) related to other comprehensive (loss) income	155.2	22.8	(15.6)
Other comprehensive (loss) income, net of tax	(466.1)	(67.6)	45.6
Comprehensive (loss) income, net of tax	$ (263.9)	$ 124.5	$ 206.8

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Common Stock	Common Stock Cumulative Effect, Period of Adoption, Adjustment	Common Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjusted Balance	Restricted Stock [Member]
Stockholders' Equity Attributable to Parent	$ 2,013.9	$ (24.1)	$ 1,989.8	$ 1,049.3	$ 0	$ 1,049.3	$ 953.6	$ (24.1)	$ 929.5	$ (11)	$ 0	$ 11
Net income	161.2			0			161.2			0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ 45.6			0			0			45.6
Stock Repurchased and Retired During Period, Shares	3,578,743
Common shares purchased and retired	$ (116.8)			(116.8)			0			0
Stock issued during period, new issues (in shares)	19,491
Stock issued during period, RSU (in shares)	332,085
Stock Issued During Period, Value, New Issues	$ 0			0			0			0
Non-vested common shares forfeited or canceled	0			0			0			0
Stock compensation expense	1.1			1.1			0			0
Stock compensation expense	7.5			7.5			0			0			$ 7.5
APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition	$ (128.6)			0			(128.6)			0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	34,912
Dividends declared (in usd per share)	$ 2
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	111,539
Shares tendered in payment of option price and income tax withholding amounts, shares	26,124
Stockholders' Equity Attributable to Parent	$ 1,959.8			941.1			962.1			(56.6)
Common Stock, Value, Issued	0			0			0			0
Net income	192.1			0			192.1			0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ (67.6)			0			0			(67.6)
Stock Repurchased and Retired During Period, Shares	128,171
Common shares purchased and retired	$ (5.4)			(5.4)			0			0
Stock issued during period, new issues (in shares)	19,081
Stock issued during period, RSU (in shares)	241,307
Stock Issued During Period, Value, New Issues	$ 0			0			0			0
Non-vested common shares forfeited or canceled	0			0			0			0
Stock compensation expense	0.4			0.4			0			0
Stock compensation expense	8.9			8.9			0			0			8.9
APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition	$ (101.6)			0			(101.6)			0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	73,044
Dividends declared (in usd per share)	$ 1.64
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	45,484
Shares tendered in payment of option price and income tax withholding amounts, shares	6,982
Stockholders' Equity Attributable to Parent	$ 1,986.6			945			1,052.6			(11)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(11)
Common Stock, Value, Issued	0			0			0			0
Net income	202.2			0			202.2			0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ (466.1)			0			0			(466.1)
Stock Repurchased and Retired During Period, Shares	5,040,896
Common shares purchased and retired	$ (199)			(199)			0			0
Stock issued during period, new issues (in shares)	46,913,370
Stock issued during period, RSU (in shares)	458,177
Stock Issued During Period, Value, New Issues	$ 1,722.5			1,722.5			0			0
Non-vested common shares forfeited or canceled	0			0			0			0
Stock compensation expense	0.1			0.1			0			0
Stock compensation expense	9.6			9.6			0			0			$ 9.6
APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition	$ (182.1)			0			(182.1)			0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	106,891
Dividends declared (in usd per share)	$ 1.70
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	17,807
Shares tendered in payment of option price and income tax withholding amounts, shares	4,877
Stockholders' Equity Attributable to Parent	$ 3,073.8			2,478.2			1,072.7			(477.1)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(477.1)
Common Stock, Value, Issued	$ 0			$ 0			$ 0			$ 0

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Stockholders' Equity [Abstract]
Stock Repurchased and Retired During Period, Shares	5,040,896	128,171	3,578,743
Stock issued during period, new issues (in shares)	46,913,370	19,081	19,491
Stock issued during period, RSU (in shares)	458,177	241,307	332,085
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	106,891	73,044	34,912
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	17,807	45,484	111,539
Shares tendered in payment of option price and income tax withholding amounts, shares	4,877	6,982	26,124
Dividends declared (in usd per share)	$ 1.70	$ 1.64	$ 2

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income	$ 202.2	$ 192.1	$ 161.2
Adjustments to reconcile net income from operations to net cash provided by operating activities:
Provision for (reversal of) credit losses	82.7	(14.6)	56.9
Net (gain) loss on disposal of premises and equipment	(2)	(1.8)	0.3
Depreciation and amortization	55.5	44.4	45.1
Net premium amortization on investment securities	17	38.8	15.9
Net loss (gain) on investment securities transactions	24.4	(1.1)	(0.3)
Realized and unrealized net gains on mortgage banking activities	(9.4)	(26.2)	(49.3)
Net gain on sale of investments in unrelated entities	0	0	(1)
Net gain on sale of OREO	(0.7)	(0.3)	(0.9)
Write-downs of OREO and other assets pending disposal	2.8	0	0.1
Gain (Loss) on Extinguishment of Debt	(1.4)	0	0
Mortgage servicing rights impairment (recovery)	(3.4)	(6.9)	9.9
Deferred taxes	(4.7)	5	(6.6)
Net increase in cash surrender value of company-owned life insurance	(11.1)	(6.1)	(7.6)
Stock-based compensation expense	9.6	8.9	7.5
Originations of mortgage loans held for sale	(429.5)	(817.4)	(1,404.2)
Proceeds from sales of mortgage loans held for sale	461.6	883.9	1,468.4
Changes in operating assets and liabilities:
(Increase) decrease in interest receivable	(37.8)	3.7	(4.4)
Increase in other assets	(12.9)	(16.4)	(27.7)
Increase (decrease) in accrued interest payable	8.4	(2)	(6.3)
Increase (decrease) in accounts payable and accrued expenses	183.1	(1.7)	11.3
Net cash provided by operating activities	534.4	282.3	268.3
Purchases of investment securities:
Held-to-maturity	(858.5)	(1,238)	0
Available-for-sale	(3,309.4)	(2,717.8)	(2,444.1)
Proceeds from maturities, pay-downs, calls and sales of investment securities:
Held-to-maturity	370.5	257.6	40.4
Available-for-sale	1,926.5	1,118	1,441.4
Purchases of Federal Home Loan Bank and Federal Reserve Bank Stock	(241.4)	0	0
Proceeds from Federal Home Loan Bank and Federal Reserve Bank Stock	112.2	0	0
Proceeds from bank-owned life insurance settlements	1.3	1	5
Extensions of credit to clients, net of repayments	(951.4)	467.8	(894.6)
Proceeds from sales of OREO	3.4	1.7	10.1
Proceeds from the sale of Health Savings Accounts	1.4	0	0
Proceeds from sale of investments in unrelated entities	0	0	2.2
Acquisition of bank and bank holding company, net of cash and cash equivalents received	2,006.9	0	0
Capital expenditures, net of sales	(10.5)	(10.3)	(30.2)
Net cash used in investing activities	(949)	(2,120)	(1,869.8)
Cash flows from financing activities:
Net (decrease) increase in deposits	(2,884)	2,052.6	2,553.5
Net increase (decrease) in securities sold under repurchase agreements	28.9	(40.3)	393.8
Proceeds from (Repayments of) Other Debt	2,327	0	0
Repayments of Other Long-term Debt	164.1	0	0.1
Advances on long-term debt	14.3	0	98.6
Payments of Stock Issuance Costs	(0.8)	0	0
Proceeds from issuance of common stock	0.1	0.4	1.1
Purchase and retirement of common stock	(199)	(5.4)	(116.8)
Dividends paid to common stockholders	(182.1)	(101.6)	(128.6)
Net cash used in financing activities	(1,059.7)	1,905.7	2,801.5
Net (decrease) increase in cash and cash equivalents	(1,474.3)	68	1,200
Cash and cash equivalents at beginning of period	2,344.8	2,276.8	1,076.8
Cash and cash equivalents at end of period	870.5	2,344.8	2,276.8
Supplemental disclosures of cash flow information:
Cash paid during the period for income taxes	(57.8)	(56.8)	(54.4)
Cash paid during the period for interest expense	32	19.3	32.9
Supplemental disclosures of noncash investing and financing activities:
Transfer of held-to-maturity to available-for-sale securities	10.9	0	0
Non-cash transfer of securities from available-for-sale to held-to-maturity	463.6	672.2	0
Transfer of Loans Held-for-sale to Portfolio Loans	19.8	0	0
Amortization of unrealized gains and losses on transfers of securities	12.4	0	0
Right-of-use assets obtained in exchange for operating lease liabilities	22.9	5.9	3.6
Transfer of loans to other real estate owned	0.4	0.9	3.3
Asset Acquisition, Consideration Transferred, Equity Interest Issued and Issuable	1,723.3	0	0
Capitalization of internally originated mortgage servicing rights	2.5	3.7	11.7
Supplemental schedule of noncash investing activities from acquisitions:
Investment securities	2,699	0	0
Loans held for sale	217	0	0
Loans held for investment, net	7,645.5	0	0
Premises and equipment	144.7	0	0
Goodwill	479.3	0	0
Other intangibles	72.9	0	0
Mortgage servicing rights	1.3	0	0
Company-owned life insurance	186.6	0	0
Deferred tax assets	60.2	0	0
Other real estate owned	15.8	0	0
Other assets	200.8	0	0
Total noncash assets acquired	11,824.2	0	0
Deposits	11,688	0	0
Securities sold under repurchase agreements	74	0	0
Accounts payable and accrued expenses	110.4	0	0
Long-term debt	159.3	0	0
Subordinated debentures held by subsidiary trusts	76.1	0	0
Total liabilities assumed	(12,107.8)	0	0
Securities Purchased under Agreements to Resell, Increase	$ 101.1	0	0
Finite-Lived Intangible Assets, Gross		$ 106	$ 106

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
Summary of Significant Accounting Policies	Dec. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Business . First Interstate BancSystem, Inc. (the “Parent Company” and collectively with its subsidiaries, the “Company”) is a financial and bank holding company that, through the branch offices of its bank subsidiary, provides a comprehensive range of banking products and services to individuals, businesses, municipalities, and other entities throughout Arizona, Colorado, Idaho, Iowa, Kansas, Minnesota, Missouri, Montana, Nebraska, North Dakota, Oregon, South Dakota, Washington, and Wyoming. In addition to its primary emphasis on commercial and consumer banking services, the Company also offers trust, employee benefit, investment, and insurance services through its bank subsidiary. The Company is subject to competition from other financial institutions and nonbank financial companies, and is also subject to the regulations of various government agencies and undergoes periodic examinations by those regulatory authorities. Basis of Presentation . The Company’s consolidated financial statements include the accounts of the Parent Company and its operating subsidiaries. As of December 31, 2022, the Company had one significant subsidiary, First Interstate Bank (“FIB”). All significant intercompany balances and transactions have been eliminated in consolidation. Certain reclassifications, none of which were material, have been made in the consolidated financial statements for 2021 and 2020 to conform to the 2022 presentation. These reclassifications did not change previously reported net income or stockholders’ equity. Business Combinations. The Company accounts for all business combinations using the acquisition method of accounting. Under this method of accounting, acquired assets and assumed liabilities are included with the acquirer's accounts as of the date of acquisition, with any excess of purchase price over the fair value of the net assets acquired recognized as either finite lived intangibles or capitalized as goodwill. In addition, acquisition related costs and restructuring costs are recognized as period expenses as incurred. Fair values are subject to refinement over the measurement period, not to exceed one year after the closing date. Equity Method Investments. The Company has investments in real estate joint ventures that are not consolidated because the Company does not own a majority voting interest, control the operations, or receive a majority of the losses or earnings of the joint venture. These joint ventures are accounted for using the equity method of accounting whereby the Company initially records its investment at cost (or fair value at the date of acquisition) and then subsequently adjusts the carrying value for the Company’s proportionate share of distributions and earnings or losses of the joint ventures. Variable Interest Entities. The Company’s wholly-owned business trusts, FI Statutory Trust I (“Trust I”), FI Capital Trust II (“Trust II”), FI Statutory Trust III (“Trust III”), FI Capital Trust IV (“Trust IV”), FI Statutory Trust V (“Trust V”), FI Statutory Trust VI (“Trust VI”), Northwest Bancorporation Capital Trust I (“Trust VII”), GWB Capital Trust VI (“Trust VIII”), Sunstate Bancshares Trust II (Trust IX”), Great Western Statutory Trust IV (“Trust X”), HF Financial Capital Trust III (“Trust XI”), HF Trust IV (“Trust XII”), HF Trust V (“Trust XIII”), and HF Trust VI (“Trust XIV”) are variable interest entities for which the Company is not a primary beneficiary. Accordingly, the accounts of Trust I through Trust XIV are not included in the accompanying consolidated financial statements, and are instead accounted for using the equity method of accounting. The Company has equity investments in variable interest Certified Development Entities (“CDEs”) which have received allocations under the New Markets Tax Credits Program. The underlying activities of the CDEs are community development projects designed primarily to promote community welfare, such as economic rehabilitation and development of low-income areas by providing housing, services, or jobs for residents. The maximum exposure to loss in the CDEs is the amount of equity invested and credit extended by the Company. The Company has credit protection in the form of indemnification agreements, guarantees, and collateral arrangements. Assets Held in Fiduciary or Agency Capacity. The Company holds certain trust assets in a fiduciary or agency capacity. The Company also purchases and sells federal funds as an agent. These and other assets held in an agency or fiduciary capacity are not assets of the Company and, accordingly, are not included in the accompanying consolidated financial statements. Use of Estimates. The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and income and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to change relate to the determination of the allowance for credit losses, the valuation of goodwill and intangible assets, and fair valuations of investment securities and other financial instruments. Cash and Cash Equivalents . For purposes of reporting cash flows, cash and cash equivalents include cash on hand, amounts due from banks, federal funds sold for less than three-month periods, and interest-bearing deposits in banks with original maturities of less than three months. As of December 31, 2022 and 2021, the Company had cash of $518.9 million and $2,166.1 million, respectively, on deposit with the Federal Reserve Bank (FRB). On March 15, 2020, the Federal Reserve reduced reserve requirement ratios to zero percent effective March 26, 2020. This action eliminated reserve requirements for all depository institutions. Debt Security Investments. Investments in debt securities that the Company has the positive intent and ability to hold to maturity are classified as held-to-maturity and carried at amortized cost. Investments in debt securities that may be sold in response to or in anticipation of changes in interest rates and resulting prepayment risk, or other factors, are classified as available-for-sale and carried at fair value. The unrealized gains and losses on these securities are reported, net of applicable income taxes, as a separate component of stockholders’ equity and comprehensive income. Management determines the appropriate classification of securities at the time of purchase and at each reporting date management reassesses the appropriateness of the classification. The amortized cost of debt securities classified as held-to-maturity or available-for-sale is adjusted for accretion of discounts to maturity and amortization of premiums over the estimated average life of the security, without anticipating prepayments, except for mortgage-backed securities where prepayments are anticipated, or in the case of callable securities, through the first call date, using the effective yield method. Such amortization and accretion is included in interest income. Realized gains and losses on sales are recorded on the trade date in investment securities gains and losses and determined using the specific identification method. Accrued interest receivable on investment securities totaled $38.9 million and $16.6 million at December 31, 2022 and 2021, respectively, and was reported in the accrued interest receivable line item on the consolidated balance sheets. Allowance for Credit Losses - Held-to-Maturity Securities: Management measures expected credit losses on held-to-maturity debt securities on a collective basis by major security type. Accrued interest receivable on held-to-maturity debt securities is excluded from the estimate of credit losses. The estimate of expected credit losses considers historical credit loss information that is adjusted for current conditions and reasonable and supportable forecasts. Management classifies the held-to-maturity portfolio into the following major security types: U.S. Treasury notes. U.S. Treasury notes issued by the U.S. Department of the Treasury are guaranteed by the U.S. government with very little risk to default. State, county, and municipal securities. Municipal bonds issued by municipal governments within the U.S. These types of securities are primarily composed of general obligation bonds, or municipal bonds backed by the credit and taxing power of the issuing jurisdiction and revenue obligation bonds, or municipal bonds that are financed by income-producing projects and are secured by a specified source of revenue. Municipal issues shall have at least a “BBB” rating by Moody's and/or Standard and Poor’s, or equivalent creditworthiness must be established prior to purchase. All non-rated or private placement securities must be analyzed and approved by the Company’s Credit Department and documented prior to purchase. Obligations of U.S. government agencies and entities. Securities held by the Company are primarily issued by The Federal Home Loan Mortgage Corporation, known as Freddie Mac, and The Federal National Mortgage Association, known as Fannie Mae, which are implicitly guaranteed by the U.S. government and are consistently highly rated by major rating agencies with very little risk to default. U.S. agency residential and commercial mortgage -backed securities and Collateralized Mortgage Obligations. Residential and commercial mortgage -backed securities held by the Company are primarily issued by U.S. government agencies and entities. These securities are either explicitly or implicitly guaranteed by the U.S. government, are consistently highly rated by major rating agencies with very little risk to default. Collateralized mortgage obligations include agency and non-agency residential securities which carry ratings no lower than investment grade “BBB” and pass the federal financial institutions examinations test (Collateral Mortgage Obligation volatility test) at the time of purchase. Corporate securities. Securities held by the Company are primarily comprised of corporate bonds (both senior and subordinated-debt) issued by a firm or public entity which carry ratings no lower than investment grade “BBB” or better by Moody’, Standard and Poor’s, or Kroll rating agencies. All corporate subordinated-debt securities are analyzed and approved by the Company prior to purchase. Allowance for Credit Losses - Available-For-Sale Securities: For available-for-sale debt securities in an unrealized loss position, the Company first assesses whether it intends to sell, or it is more likely than not that it will be required to sell the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the security's amortized cost basis is written down to fair value through income. For available-for-sale debt securities that do not meet the aforementioned criteria, the Company performs a qualitative assessment as to whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, management considers the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded for the credit loss, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that has not been recorded through an allowance for credit losses is recognized in other comprehensive income. Changes in the allowance for credit losses are recorded as provision for (or reversal of) credit loss expense. Losses are charged against the allowance when management believes the uncollectibility of an available-for-sale security is confirmed or when either of the criteria regarding intent or requirement to sell is met. Accrued interest receivable on available-for-sale debt securities is excluded from the estimate of credit losses. Loans Held for Sale. The Company originates certain loans intended for sale in the secondary market. Conforming agency mortgage production is sold on a servicing retained basis. Certain loans, such as government guaranteed mortgage loans, are sold on a servicing released basis. Residential loans the Company originated with the intent to sell are classified as loans held for sale and recorded at fair value, determined individually, as of the balance sheet date. The loan’s fair value includes the servicing value of the loans as well as any accrued interest. The fair value of loans held for sale are primarily determined based on quoted prices for similar loans in active markets or outstanding commitments from third-party investors. Net unrealized losses, if any, are recorded as a valuation allowance and charged to non-interest income in the consolidated statements of operations. Net gains and losses on loan sales are recorded as a component of non-interest income. Performing residential real estate loans that are held for sale are generally sold with servicing rights retained. Upon the sale of an originated loan, the mortgage servicing right is recorded at its estimated fair value. Loans that are originated and classified as held for investment are periodically sold in order to manage liquidity, asset credit quality, interest rate risk, or concentration risk. Loans that are reclassified into loans held for sale from loans held for investment, due to a change in intent, are recorded at the lower of cost or fair value less cost to sell, except for certain loans which are recorded at fair value, determined individually, as of the balance sheet date. Any changes in fair value attributable to credit deterioration at the time of transfer are charged against the allowance for credit losses. Loans Held for Investment. Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at amortized cost or principal balance outstanding. Amortized cost is the principal balance outstanding, net of purchase premiums and discounts and deferred loan fees and costs. Loan origination fees, net of certain direct origination costs, are deferred and recognized in interest income using the level-yield method without anticipating prepayments. Accrued interest receivable on loans held for investment totaled $76.5 million and $30.2 million at December 31, 2022 and 2021, respectively, and was reported in the accrued interest receivable line item on the consolidated balance sheets. Interest income is accrued on the unpaid principal balance of underlying loans. Interest income on mortgage and commercial loans is discontinued and placed on nonaccrual status at the time the loan is 90 days delinquent unless the loan is well secured and in process of collection. Mortgage loans that are 180 days past due and commercial loans are charged off to the extent principal or interest is deemed uncollectible. Consumer and credit card loans continue to accrue interest until they are charged off no later than 120 days past due unless the loan is in the process of collection. Past-due status is based on the contractual terms of the loan. In all cases, loans are placed on nonaccrual or charged off at an earlier date if collection of principal or interest is considered doubtful. All interest accrued but not received for loans placed on nonaccrual is reversed against interest income. Interest received on such loans is accounted for on the cash-basis or cost-recovery method, until qualifying for return to accrual. Under the cost-recovery method, interest income is not recognized until the loan balance is reduced to zero. Under the cash-basis method, interest income is recorded when the payment is received in cash. Loans are returned to accrual status when all the principal and interest amounts contractually due are brought current and when, in the opinion of management, the loans are estimated to be fully collectible as to both principal and interest. Purchased Credit Deteriorated (“PCD”) Loans The Company has loans acquired through acquisitions, some of which have experienced more than insignificant credit deterioration since origination. Loans that meet at least one of the following criteria are considered to have experienced more-than-insignificant credit deterioration since origination at the date of acquisition: 1) have experienced more than one delinquency of more than 60 days or 60+ days as of the acquisition date; 2) have been placed on nonaccrual status at any point since origination; 3) are special mention, substandard, doubtful as of the acquisition date; 4) have a Troubled Debt Restructuring (TDR) status as of the acquisition date; or 5) are in high-risk industries based on macroeconomic conditions and local market conditions of the acquired entity on the acquisition date. PCD loans are recorded at the amount paid for the loan. An allowance for credit losses is determined using the same methodology as other loans held for investment. The initial allowance for credit losses determined on a collective basis is allocated to individual loans. The sum of the loan’s purchase price and allowance for credit losses becomes its initial amortized cost basis. The difference between the initial amortized cost basis and the par value of the loan is a noncredit discount or premium, which is amortized into interest income over the life of the loan. Subsequent changes to the allowance for credit losses are recorded through provision expense. Allowance for Credit Losses - Loans held for investment The allowance for credit losses is a valuation account that is deducted from the loans’ amortized cost basis to present the net amount expected to be collected over the life of the loans. Loans are charged off against the allowance when management believes the uncollectibility of a loan balance is confirmed. When forecasting expected recoveries, the amounts should not exceed the aggregate of amounts that have previously been or are expected to be charged-off loans. The Company has elected to not forecast recoveries. Management estimates the allowance balance using relevant available information, from internal and external sources, relating to past events, current conditions, and reasonable and supportable forecasts. Historical credit loss experience provides the basis for the estimation of expected credit losses. Adjustments to historical loss information are made for differences in current loan-specific risk characteristics such as differences in underwriting standards, portfolio mix, delinquency level, or term as well as for changes in environmental and economic conditions, such as changes in unemployment rates, property values, or other relevant factors. The allowance for credit losses is measured on a collective (pool) basis when similar risk characteristics exist. The Company applies Probability of Default (PD) and Loss Given Default (LGD) methodologies for all portfolio segments. The Company uses a Transition Matrix (TM) for PD components of the methodology and a historical average for the LGD components of methodology. The PD and LGD is applied to the current principal balance as of the reporting date. The TM determines the PD by tracking the historical movement of loans between loan risk tiers over a defined period of time. The Company currently has 17 portfolio segments for which we track monthly movement between either risk ratings or delinquency band. While the TM functions similarly across all portfolio segments, generally speaking, commercial portfolios use the Company’s risk rating scale and consumer portfolios use the delinquency band. Loans using risk ratings are scored utilizing the Company’s risk rating scale. The risk rating scale is 1-10, with 1 being the best rating, 6 being a pass but on watch, and 7-10 being various stages of criticized loans. Risk ratings 8 or greater and in a non-accrual status are considered in a defaulted state. Loans using delinquency band are measured using a 5-grade band, with 1 being current and 5 being 90 or more days past due. The LGD used as the basis for the estimate of credit losses is comprised of the Company’s historical loss experience from 2008 to the current period, based on a migration analysis of our historical loss experience, designed to account for credit deterioration. The model compares the most recent period losses to prior period defaults to calculate the LGD, which is averaged over the historical observations. Economic scenarios and forecasts along with current portfolio conditions and trends are monitored and accounted for through the Company’s qualitative framework. The Company utilizes a one-year forecast period with immediate reversion to historical loss rates. The Company segments the loan portfolio into pools based on the following risk characteristics: financial asset type, collateral type, loan characteristics, credit characteristics, outstanding loan balances, contractual terms and prepayment assumptions, vintage, industry of borrower and concentrations, and historical or expected credit loss. The Company has identified the following portfolio segments and measures the allowance for credit losses using the following methods: Portfolio segments using the Company’s risk ratings include the following: Commercial real estate non-owner-occupied loans. These loans include a mix of variable and fixed rate non-farm, non-residential real estate loans secured by non-owner-occupied properties. Commercial real estate non-owner-occupied loans are generally secured by first liens on income-producing real estate and generally mature in less than 10 years. Commercial real estate owner-occupied loans. Non-farm, non-residential real estate loans are generally secured by first liens on real estate where the owner occupant is the majority tenant of the property and generally mature in less than 10 years. Commercial real estate multi-family loans. Commercial real estate multifamily loans are generally secured by first liens on income-producing rental real estate consisting of five or more residential dwelling units. Multi-family loans generally mature in less than 10 years. Construction land acquisition and development loans. Construction land acquisition and development loans are primarily to commercial builders for residential lot development and the construction of single-family residences and commercial real estate properties. Construction loans are generally underwritten pursuant to pre-approved permanent financing. During the construction phase the borrower pays interest only. Construction land acquisition and development loans generally mature in three years or less. Residential construction loans. Residential construction loans are primarily to commercial builders or owner occupants for the construction of single-family residences. Construction loans are generally underwritten pursuant to credit worthiness or pre-qualification for permanent financing. During the construction phase the borrower pays interest only. Residential construction loans generally transition to a permanent residential loan or mature in two years or less. Commercial construction loans. Commercial construction loans are primarily to commercial builders for commercial real estate properties. Construction loans are generally underwritten pursuant to credit worthiness or pre-qualification for permanent financing. During the construction phase the borrower pays interest only. Commercial construction loans generally transition to a permanent commercial real estate loan or mature in two years or less. Agricultural real estate loans. These include loans secured by farmland or ranchland consisting of short, intermediate, and long-term structures to experienced agriculturalists who have demonstrated management capabilities, established production and historical financial performance. Agricultural real estate loans generally mature in ten years or less. Commercial and floor plan loans. The Company provides a mix of variable and fixed rate commercial loans in addition to loans to finance dealership floor inventories. The loans are typically made to small and medium-sized manufacturing, wholesale, retail, and service businesses for working capital needs and business expansions. Commercial loans generally include lines of credit, business credit cards, and loans with maturities of five years or less and outstanding balances tend to be cyclical in nature. The loans are generally made with business operations as the primary source of repayment, and are typically collateralized by inventory, accounts receivable, equipment, and/or personal guarantees. Commercial and floor plan loans generally mature in seven years or less. Commercial purpose secured by 1-4 family loans. These include loans for commercial purposes secured by 1-4 family residential property. Commercial purpose loans secured by 1-4 family generally mature in seven years or less. Agricultural loans. Agricultural loans generally consist of short and medium-term loans and lines of credit that are primarily used for crops, livestock, equipment, and general operations. Agricultural loans are ordinarily secured by assets such as livestock or equipment and are repaid from the operations of the farm or ranch. Agricultural loans generally have maturities of seven years or less, with operating lines for one production season. Portfolio segments utilizing the delinquency bands include the following: Consumer indirect loans. These include loan contracts advanced for the purchase of automobiles, boats, and other consumer goods from the consumer product dealer networks within the market areas we serve. Indirect dealer loans are generally secured by automobiles, recreational vehicles, boats, and other types of personal property and are made on an installment basis. Consumer indirect line loans generally mature in seven years or less. Consumer direct and advance line loans. These loans are originated for a variety of purposes including the purchase of automobiles, boats and other consumer goods, home improvements, medical expenses, vehicle repairs, debt consolidation, and planned expenses. Consumer direct and advance line loans generally mature in seven years or less. Consumer credit card loans. These are lines of credit offered to clients in our market areas that are generally floating rate loans and include both unsecured and secured lines. Consumer credit card loans generally do not have stated maturities but are reviewed periodically and are unconditionally cancellable. Consumer home equity and home equity lines of credit (“HELOC”). These include home equity loans and lines of credit that are secured by residential property. Consumer home equity loans generally mature in 15 years or less and HELOC loans generally mature in 25 years or less. Residential 1-4 family and multi-family lending. These are loans to finance the purchase or refinance of residential property which are typically secured by first liens, inclusive of 1-4 family as well as 5+ residential properties. Residential 1-4 family loans generally mature within 15 years but can be up to 30 years. Multi-family loans generally mature in 10 years or less. Commercial credit card loans. These are lines of credit for commercial purposes that are generally floating rate loans and include both unsecured and secured lines. For CECL related segmentation, commercial credit card loans are modeled separately but are reported under Commercial. Commercial credit card loans generally do not have stated maturities but are reviewed periodically and are unconditionally cancellable. Agricultural credit card loans. Lines of credit for agricultural purposes that are generally floating rate loans and are unsecured or secured. For CECL related segmentation, agricultural credit card loans are modeled separately but are reported under Commercial. Agricultural credit card loans generally do not have stated maturities but are reviewed periodically and are unconditionally cancellable. Contractual Term . Expected credit losses are estimated over the contractual term of the loans, adjusted for expected prepayments when appropriate. The contractual term excludes expected extensions, renewals, and modifications unless either management has a reasonable expectation at the reporting date that a TDR will be executed with an individual borrower or the extension or renewal options are included in the original or modified contract at the reporting date and are not unconditionally cancellable by the Company. A loan for which the terms have been modified resulting in a concession, and for which the borrower is experiencing financial difficulties, is considered to be a TDR. The allowance for credit loss on a TDR is measured using the same method as all other loans held for investment, except when the value of a concession is individually evaluated using the discounted cash flow method. When the value of a concession is measured using the discounted cash flow method, the allowance for credit loss is determined by discounting the expected future cash flows at the original interest rate of the loan. Allowance for Credit Losses on Off-Balance Sheet Credit Exposures. The Company estimates expected credit losses over the contractual period in which the Company is exposed to credit risk via a contractual obligation to extend credit unless that obligation is unconditionally cancellable by the Company. Management considers our unused credit card lines and federal fund lines, extended to others, to be considered unconditionally cancellable. The allowance for credit losses on off-balance sheet credit exposures is adjusted as a provision for credit loss expense. The estimate considers the likelihood that funding will occur and an estimate of expected credit losses on commitments expected to be funded over the estimated life. The Company has identified commitments to extend credit and standby letters of credit determined not to be unconditionally cancellable as categories with off-balance sheet credit exposures and uses the commitment balance, expected loss rate, and utilization rate as primary assumptions to develop the allowance for credit losses on those exposures. The loss rate expectation is the same for both the unfunded and funded portions of the credit exposure. The utilization rate represents management’s best estimate of the probability that the unfunded portion of the commitment will be funded given existing economic conditions. Goodwill . The excess purchase price over the fair value of net assets from acquisitions, or goodwill, is evaluated for impairment at least annually and on an interim basis if an event or circumstance indicates that it is likely impairment has occurred. Goodwill impairment is determined by comparing the fair value of a reporting unit to its carrying amount. In any given year the Company may elect to perform a qualitative assessment to determine whether it is more likely than not that the fair value of a reporting unit is in excess of its carrying value. If it is not more likely than not that the fair value of the reporting unit is in excess of the carrying value, or if the Company elects to bypass the qualitative assessment, a quantitative impairment test is performed. In performing a quantitative test for impairment, the fair value of net assets is estimated based on analyses of the Company’s market value, discounted cash flows and peer values. The determination of goodwill impairment is sensitive to market-based economics and other key assumptions used in determining or allocating fair value. Variability in the market and changes in assumptions or subjective measurements used to allocate fair value are reasonably possible and may have a material impact on our consolidated financial statements or results of operations. Core Deposit and Other Customer Relationship Intangibles. Intangible assets consist of core deposit intangibles and other customer relationship intangibles. Core deposit intangibles represent the intangible value of depositor rel

Acquisitions

Acquisitions	12 Months Ended
Acquisitions	Dec. 31, 2022
Business Combinations [Abstract]
Acquisitions	ACQUISITION Great Western Bank. On September 15, 2021, the Company entered into a definitive agreement (“Agreement”) to acquire 100% of the outstanding stock of Great Western Bancorp, Inc. (“Great Western”), the parent company of Great Western Bank (“GWB”), a Sioux Falls, South Dakota based community bank with 174 banking offices across Arizona, Colorado, Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, and South Dakota. The acquisition of GWB expanded the Company’s geographical footprint with an enhanced platform for future growth. Consideration for the acquisition was $1,723.3 million, consisting of the issuance of 46.9 million shares of the Company’s Class A common stock valued at $36.76 per share, which was the opening price of the Company’s Class A common stock as quoted on the NASDAQ stock market on the acquisition date. The acquisition was completed on February 1, 2022. The Company accounted for this transaction under the acquisition method of accounting in accordance with ASC 805, Business Combinations , which requires purchased assets and liabilities assumed and consideration exchanged to be recorded at their respective estimated fair values at the date of acquisition. The determination of estimated fair values required management to make certain estimates about discount rates, future expected cash flows, and market conditions at the time of the acquisition, as well as other future events that are highly subjective in nature. This determination is subject to refinement for up to one year after the closing date of the acquisition as additional information relative to the closing date fair values becomes available and such information is considered final, whichever is earlier. The following table provides the purchase price allocation as of the acquisition date and the Great Western assets acquired and liabilities assumed at their estimated fair value as of the acquisition date as amended for measurement period adjustments as of December 31, 2022. We recorded the estimate of fair value based on valuations at the acquisition date. The excess value of the consideration paid over the fair value of assets acquired and liabilities assumed was recorded as goodwill. The purchase price allocation resulted in goodwill of $479.3 million, of which $31.7 million is deductible for income tax purposes. Goodwill resulting from the acquisition was allocated to the Company’s one operating segment, community banking, and consists largely of the synergies and economies of scale expected from combining the operations of Great Western and the Company. All amounts reported were finalized during the fourth quarter of 2022. As of February 1, 2022 Assets acquired: Cash and cash equivalents $ 2,006.9 Investment securities 2,699.0 Securities purchased under agreement to resell 101.1 Loans held for sale 217.0 Loans held for investment 7,705.0 Allowance for credit losses (59.5) Premises and equipment, including right of use lease assets 144.7 Other real estate owned (“OREO”) 15.8 Company owned life insurance 186.6 Core deposit intangibles 50.1 Customer relationship intangible 22.8 Mortgage servicing rights 1.3 Deferred tax assets, net 60.2 Other assets 200.8 Total assets acquired 13,351.8 Liabilities assumed: Deposits 11,688.0 Securities sold under repurchase agreements 74.0 Accrued expenses and other liabilities 110.4 FHLB advances 122.9 Subordinated debt 36.4 Subordinated debentures held by subsidiary trusts 76.1 Total liabilities assumed 12,107.8 Net assets acquired $ 1,244.0 Consideration paid: Class A common stock 1,723.3 Total consideration paid (1) $ 1,723.3 Goodwill $ 479.3 (1) Includes $13 thousand of cash paid in lieu of fractional shares. As of December 31, 2022, the Company recorded measurement period adjustments to the fair value marks as indicated in the table below. These adjustments resulted in a net decrease to goodwill of $36.7 million from the March 31, 2022 reported balances. The related impact to net income that would have been recognized in previous periods if the adjustments were recognized as of the acquisition date was not material to the consolidated financial statements. Asset adjustments: Loans held for sale $ 35.1 Loans held for investment (8.4) Allowance for credit losses 24.8 Premises and equipment 0.6 Core deposit intangibles 1.0 Deferred tax assets (15.9) Other assets 2.8 Total asset adjustments $ 40.0 Liability adjustments: Accrued expenses and other liabilities $ 3.3 Total liability adjustments $ 3.3 Net adjustment to goodwill $ (36.7) The Company determined the fair value of loans, core deposit and customer relationship intangible assets, investment securities, premises and equipment, leases, mortgage servicing rights, deposits, FHLB advances, subordinated debt, and subordinated debentures held by subsidiary trusts with the assistance of third-party valuation specialists. The following is a description of the methods used to determine the fair values of significant assets and liabilities presented above. Cash and cash equivalents The carrying amount of these assets is a reasonable estimate of fair value based on the short-term nature of these assets. Investment Securities Fair values for securities are based on quoted market prices, where available. If quoted market prices are not available, fair value estimates are based on observable inputs including quoted market prices for similar instruments, quoted market prices that are not in an active market or other inputs that are observable in the market. In the absence of observable inputs, fair value is estimated based on pricing models and/or discounted cash flow methodologies. Loans held for sale The loans held for sale portfolio was recorded at fair value based on discounted payoffs and quotes or bids from third party investors, or based on the terms of the loans, such as interest rate, maturity date, reset term, as well as sales, quotes, or bids of similar assets. Loans held for investment A valuation of the loans held for investment portfolio was performed by a third party as of the acquisition date in accordance with ASC 820 to assess the fair value of the loan portfolio, considering adjustments for interest rate risk, required equity return, servicing, credit, and liquidity risk. The loans held for investment portfolio was segmented into two groups including purchase credit deteriorated (PCD) loans and non-PCD loans. The non-PCD loans were pooled based on similar characteristics, such as loan type, fixed or adjustable interest rates, payment type, index rate and caps/floors, and non-accrual status. The PCD loans were valued at the loan level with similar characteristics noted above. The fair value was calculated using a discounted cash flow analysis to estimate the fair value of the loans using assumptions for the coupon rates, remaining maturities, prepayment speeds, projected default probabilities, loss given defaults, and estimates of prevailing discount rates. The discount rate utilized to analyze fair value considered the cost of funds rate, capital charge, servicing costs, liquidity premium, and risk premium, mostly based on industry standards. The discounted cash flow approach models the credit losses directly in the projected cash flows. The Company estimated the credit risks and principal losses of the loans using the Company’s assumptions of probability of default, loss given default, and foreclosures. The Company is required to record PCD assets, defined as a more-than-insignificant deterioration in credit quality since origination or issuance, at the purchase price plus the allowance for credit losses expected at the time of acquisition. Under this method, there is no credit loss expense affecting net income on acquisition of PCD assets. Changes in estimates of expected credit losses after acquisition are recognized in subsequent periods as credit loss expense (or reversal of credit loss expense) arise. Any non-credit discount or premium resulting from acquiring a pool of purchased financial assets with credit deterioration is allocated to each individual asset. At the acquisition date, the initial allowance for credit losses determined on a collective basis is allocated to individual assets to appropriately allocate any non-credit discount or premium. The non-credit discount or premium, after the adjustment for the allowance for credit losses, is accreted to interest income using the interest method based on the effective interest rate determined after the adjustment for credit losses at the adoption date. Information regarding loans acquired at the acquisition date as amended for measurement period adjustments as of December 31, 2022 were as follows: (In millions) PCD loans: Unpaid principal balance $ 979.2 Principal amounts previously written off by GWB (238.7) Interest applied to principal by GWB (18.1) Adjusted unpaid principal balance 722.4 Credit discount (69.2) Discount attributable to other factors (29.9) Fair value 623.3 Allowance for credit losses 59.5 Amortized cost basis 682.8 Non-PCD loans: Unpaid principal balance 7,107.9 Credit discount (1) (76.5) Non-credit discount (9.2) Fair value 7,022.2 Amortized cost basis $ 7,705.0 (1) Represents the best estimate of the contractual cash flows not expected to be collected as of the acquisition date. Core deposit intangible Core deposit intangible assets of $50.1 million on non-maturing deposits were determined by evaluating the underlying characteristics of the deposit relationships, including customer attrition, deposit interest rates and maintenance costs, and costs of alternative funding using the discounted cash flow approach. The core deposit intangibles represent the costs saved by the Company between maintaining the existing deposits and obtaining alternative funds over the life of the deposit base. These costs are amortized using an accelerated method over the estimated useful life of 10 years for the related deposits. Customer relationship intangible Customer relationship intangible assets of $22.8 million were determined using an excess earnings model associated with the expected fee income related to the underlying client relationships and is being amortized using the straight-line method over the estimated useful life of 12 years. Premises and equipment The fair values of premises are based on a market approach, using third-party appraisals and other analysis of value for land and premises. Deposits The fair values used for the demand and savings deposits equal the amounts payable on demand at the acquisition date. In determining the fair value of certificates of deposit, the cash flows of the contractual interest payments during the specific period of the certificates of deposit and scheduled principal payout were discounted to present value at market-based interest rates. FHLB advances The fair value of fixed rate FHLB advances was determined using a discounted cash flow approach. The cash flows of the advances were projected based on scheduled payments of the fixed rate advances, which factored in prepayment fees. The cash flows were then discounted to present value using the FHLB rates as of February 1, 2022. Subordinated debt and subordinated debentures held by subsidiary trusts The fair value of subordinated debt and subordinated debentures held by subsidiary trusts was determined by using a discounted cash flow method using a market participant discount rate for similar instruments over the remaining terms. Acquisition related expenses related to the GWB acquisition of $118.9 million and $11.6 million for the years ended December 31, 2022 and 2021, respectively, were included as a component of non-interest expense in the consolidated statements of income, of which approximately $26.8 million and $9.0 million were acquisition related costs as defined by ASC 805 for the years ended December 31, 2022 and 2021, respectively. During the year ended December 31, 2022, the Company contributed $21.5 million to the First Interstate Foundation and reimbursed an aggregate of $8.2 million of the Scott family control group’s acquisition expenses pursuant to the Agreement. The accompanying consolidated statements of income for the year ended December 31, 2022, include the results of operations of the acquired entity from the February 1, 2022 acquisition date. The disclosure of GWB post-acquisition revenue and net income is not practical due to the combining of certain GWB operations with and into FIB as of the acquisition date. GWB was merged with our existing bank subsidiary, First Interstate Bank, contemporaneously with the closing of the parent company merger. The core system conversion was completed on May 23, 2022. The following table presents certain pro forma financial information for the years ended December 31, 2022 and 2021 as if GWB had been acquired on January 1, 2021. This pro forma information combines the historical results of GWB with the Company’s consolidated historical results and includes certain adjustments reflecting the estimated impact of certain fair value adjustments for the respective periods. The pro forma information is not indicative of what would have occurred had the acquisition occurred at the beginning of the year prior to the acquisition. The pro forma information does not consider any changes to the provision for credit losses resulting from recording loan assets at fair value, cost savings, or business synergies. As a result, actual amounts would have differed from the pro forma information presented, and the differences could be significant. December 31, 2022 2021 Total revenues $ 1,223.3 $ 1,200.9 Net income $ 351.6 $ 243.3 Earnings per common share (Basic) $ 3.28 $ 2.24 Earnings per common share (Diluted) $ 3.28 $ 2.24

Goodwill and Core Deposit Intan

Goodwill and Core Deposit Intangibles	12 Months Ended
Goodwill and Core Deposit Intangibles	Dec. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Core Deposit Intangibles	GOODWILL AND OTHER INTANGIBLES Goodwill The following table details changes in the recorded amount of goodwill as of the dates indicated: Year Ended December 31, 2022 2021 Net carrying value at beginning of period $ 621.6 $ 621.6 Additions to goodwill from acquisition 479.3 — Net carrying value at end of period $ 1,100.9 $ 621.6 The Company performed its annual impairment assessment as of July 1, 2022 and 2021 and concluded that there was no impairment to goodwill. In addition, there were no events or circumstances that occurred during the second half of 2022 that would more-likely-than-not reduce the fair value of the Company’s reporting unit below its carrying value. The Company did not perform interim impairment testing as of December 31, 2022. Other Intangible Assets Other intangible assets are comprised of core deposit intangibles (“CDI”) and other customer relationship intangibles (“OCRI”) and amounted to the following at December 31, 2022 and 2021: December 31, 2022 CDI OCRI Total Gross other intangible assets, at beginning of the period $ 106.0 $ — $ 106.0 Amounts established through acquisition 50.1 22.8 72.9 Reductions due to sale of health savings accounts (1.4) — (1.4) Accumulated amortization (78.8) (1.7) (80.5) Net other intangible assets, end of period $ 75.9 $ 21.1 $ 97.0 December 31, 2021 Gross other intangible assets, at beginning of the period $ 106.0 $ — $ 106.0 Accumulated amortization (64.7) — (64.7) Net other intangible assets, end of period $ 41.3 $ — $ 41.3 The Company recorded $15.9 million, $9.9 million and $10.9 million of other intangible asset amortization expense for the years ended December 31, 2022, 2021, and 2020 respectively. CDI and OCRI are evaluated for impairment if events and circumstances indicate a possible impairment. CDI is amortized using an accelerated method based on the estimated weighted average useful lives of the related deposits, which is generally 10 years. OCRI is amortized using a straight-line method over its estimated useful life of 12 years based on customer revenue attrition on an annualized basis. The following table provides the estimated aggregate future amortization expense of other intangible assets: Years ending December 31, CDI OCRI Total 2023 $ 13.7 $ 1.9 $ 15.6 2024 12.7 1.9 14.6 2025 11.8 1.9 13.7 2026 10.9 1.9 12.8 2027 8.2 1.9 10.1 Thereafter 18.6 11.6 30.2 Total $ 75.9 $ 21.1 $ 97.0

Investment Securities

Investment Securities	12 Months Ended
Investment Securities	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Investment Securities	INVESTMENT SECURITIES The amortized cost and approximate fair values of investment securities are summarized as follows: December 31, 2022 Amortized Gross Gross Estimated Available-for-Sale U.S. Treasury notes $ 675.1 $ 2.1 $ (34.5) $ 642.7 State, county, and municipal securities 314.3 — (50.6) 263.7 Obligations of U.S. government agencies 216.2 — (17.3) 198.9 U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 4,685.5 0.2 (426.0) 4,259.7 Private mortgage-backed securities 264.9 — (36.9) 228.0 Collateralized loan obligations 1,145.2 — (33.6) 1,111.6 Corporate Securities 272.3 — (30.8) 241.5 Total $ 7,573.5 $ 2.3 $ (629.7) $ 6,946.1 December 31, 2022 Amortized Allowance for Credit Losses Net Carrying Amount Gross Unrealized Gains Gross Estimated Held-to Maturity U.S. Treasury notes $ 396.6 $ — $ 396.6 $ — $ (10.2) $ 386.4 State, county, and municipal securities 181.2 (0.1) 181.1 0.2 (31.6) 149.7 Obligations of U.S. government agencies 351.7 — 351.7 — (49.6) 302.1 U.S agency residential & commercial mortgage-backed securities & collateralized mortgage obligations (1) 2,444.1 — 2,444.1 0.2 (301.6) 2,142.7 Corporate securities 80.1 (1.8) 78.3 — (7.0) 71.3 Total $ 3,453.7 $ (1.9) $ 3,451.8 $ 0.4 $ (400.0) $ 3,052.2 (1) Amortized cost presented above include $20.2 million of unamortized losses and $14.2 million of unamortized gains related to the 2021 and 2022 transfer of securities from available-for-sale to held-to-maturity. December 31, 2021 Amortized Gross Gross Estimated Available-for-Sale U.S. Treasury notes $ 697.6 $ — $ (12.9) $ 684.7 State, county, and municipal securities 434.7 2.1 (9.3) 427.5 Obligations of U.S. government agencies 356.0 0.1 (9.2) 346.9 U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 2,027.3 14.1 (23.3) 2,018.1 Private mortgage-backed securities 174.4 0.1 (1.1) 173.4 Collateralized loan obligation 898.2 1.2 — 899.4 Corporate Securities 271.1 3.0 (3.6) 270.5 Total $ 4,859.3 $ 20.6 $ (59.4) $ 4,820.5 December 31, 2021 Amortized Allowance for Credit Losses Net Carrying Amount Gross Gross Estimated Held-to Maturity State, county, and municipal securities $ 67.6 $ — $ 67.6 $ 2.0 $ (0.4) $ 69.2 U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 1,609.0 — 1,609.0 13.2 (35.3) 1,586.9 Corporate securities 11.0 — 11.0 0.4 — 11.4 Total $ 1,687.6 $ — $ 1,687.6 $ 15.6 $ (35.7) $ 1,667.5 (1) Amortized cost presented above include $20.1 million of unamortized gains in U.S. agency residential and commercial mortgage-backed securities and collateralized mortgage obligations related to the 2021 transfer of securities from available-for-sale to held-to-maturity. On February 1, 2022, in conjunction with the acquisition of GWB and under ASC 320, the Company transferred debt securities classified as held-to-maturity with an amortized cost of $10.7 million and an estimated fair value of $10.9 million to the available-for-sale category classification and transferred debt securities classified as available-for-sale with an amortized cost of $485.9 million and an estimated fair value of $463.6 million to the held-to-maturity classification to maintain the Company’s intended risk profile. The transfer of debt securities into the available-for-sale and held-to-maturity categories were recorded at fair value on the date of transfer. This discount, as well as the related unrealized loss in accumulated other comprehensive income (loss), will be amortized into interest income as a yield adjustment over the remaining term of the securities. The amortization of the unrealized loss reported in accumulated other comprehensive (loss) income will offset the effect on interest income of the accretion of the discount. No gains or losses were recorded at the time of transfer. The following tables show the gross unrealized losses and fair values of investment securities, aggregated by investment category, and the length of time individual investment securities have been in a continuous unrealized loss position, as of December 31, 2022 and 2021. Less than 12 Months 12 Months or More Total December 31, 2022 Fair Gross Fair Gross Fair Gross Available-for-Sale U.S. Treasury notes $ 168.8 $ (4.7) $ 170.4 $ (29.8) $ 339.2 $ (34.5) State, county, and municipal securities 104.9 (9.0) 146.1 (41.6) 251.0 (50.6) Obligations of U.S. government agencies 152.2 (10.1) 46.1 (7.2) 198.3 (17.3) U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 3,299.7 (262.3) 948.4 (163.7) 4,248.1 (426.0) Private mortgage-backed securities 133.1 (19.1) 94.9 (17.8) 228.0 (36.9) Collateralized loan obligations 1,082.6 (33.1) 28.9 (0.5) 1,111.5 (33.6) Corporate securities 130.6 (8.3) 110.8 (22.5) 241.4 (30.8) Total $ 5,071.9 $ (346.6) $ 1,545.6 $ (283.1) $ 6,617.5 $ (629.7) Less than 12 Months 12 Months or More Total December 31, 2022 Fair Gross Fair Gross Fair Gross Held-to-Maturity U.S. Treasury notes $ 386.4 $ (10.2) $ — $ — $ 386.4 $ (10.2) State, county and municipal securities 33.8 (4.0) 96.7 (27.6) 130.5 (31.6) Obligations of U.S. government agencies 86.1 (9.9) 216.0 (39.7) 302.1 (49.6) U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 1,349.4 (156.1) 762.5 (145.5) 2,111.9 (301.6) Corporate securities 68.2 (7.0) — — 68.2 (7.0) Total $ 1,923.9 $ (187.2) $ 1,075.2 $ (212.8) $ 2,999.1 $ (400.0) Less than 12 Months 12 Months or More Total December 31, 2021 Fair Gross Fair Gross Fair Gross Available-for-Sale U.S. Treasury notes $ 684.7 $ (12.9) $ — $ — $ 684.7 $ (12.9) State, county, and municipal securities 278.7 (9.1) 5.0 (0.2) 283.7 (9.3) Obligations of U.S. government agencies 297.0 (8.9) 16.4 (0.3) 313.4 (9.2) U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 1,262.8 (23.0) 26.4 (0.3) 1,289.2 (23.3) Private mortgage-backed securities 127.2 (1.1) — — 127.2 (1.1) Corporate securities 109.9 (3.3) 20.9 (0.3) 130.8 (3.6) Total $ 2,760.3 $ (58.3) $ 68.7 $ (1.1) $ 2,829.0 $ (59.4) Less than 12 Months 12 Months or More Total December 31, 2021 Fair Gross Fair Gross Fair Gross Held-to-Maturity State, county and municipal securities $ 29.0 $ (0.4) $ — $ — $ 29.0 $ (0.4) U.S. agency residential mortgage-backed 1,038.7 (35.3) — — 1,038.7 (35.3) Total $ 1,067.7 $ (35.7) $ — $ — $ 1,067.7 $ (35.7) As of December 31, 2022 and 2021, there were no holdings of securities of any issuer, other than the U.S. government and its agencies, in an amount greater than 10% of stockholders’ equity. The Company acquired $2,699.0 million of investment securities in connection with the acquisition of GWB. Such securities were evaluated and it was determined that there were no investment securities that met the definition of a PCD asset and none were classified as PCD upon acquisition. The Company determines credit losses on both available-for-sale and held-to-maturity investment securities by a discounted cash flow approach using the security’s effective interest rate at the time of purchase or upon acquisition. The allowance for credit losses is measured as the amount by which an investment security’s amortized cost exceeds the net present value of expected future cash flows. However, the amount of credit losses for available-for-sale investment securities is limited to the amount of a security’s unrealized loss. Credit losses on held-to-maturity investment securities are representative of current expected credit losses that may be incurred over the life of the investment. The allowance for credit losses is established through a charge to provision for credit losses in current period earnings. The available-for-sale securities portfolio contains securities that are guaranteed by a sovereign entity or are generally considered to have non-credit related risks, such as interest rate risk or prepayment and liquidity factors. The Company considers whether the securities are issued by the federal government or its agencies and whether downgrades by bond rating agencies have occurred. The Company had no allowance for credit losses for available-for-sale investment securities as of December 31, 2022 and 2021. As of December 31, 2022 and 2021, the Company had 1,222 and 285 individual investment securities, respectively, that were in an unrealized loss position, which was related primarily to fluctuations in current interest rates. As of December 31, 2022, the Company had the intent and ability to hold these investment securities for a period of time sufficient to allow for an anticipated recovery. The following table presents the activity in the allowance for credit losses related to held-to-maturity securities classified as corporate and state, county, and municipal securities: Year Ended December 31, 2022 2021 2020 Beginning balance $ — $ — $ — Provision for credit loss expense 1.9 — — Ending balance of allowance for credit losses $ 1.9 $ — $ — On a quarterly basis, the Company refreshes the credit quality of each held-to-maturity security. The following table summarizes the credit quality indicators of held-to-maturity securities at amortized cost for the periods indicated: December 31, 2022 AAA AA A BBB BB Not Rated Total U.S. Treasury notes $ 396.6 $ — $ — $ — $ — $ — $ 396.6 State, county, and municipal securities 68.3 92.8 11.5 — — 8.6 181.2 Obligations of U.S. government agencies 351.7 — — — — — 351.7 U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations FNMA/FHLMC 2,233.6 — — — — — 2,233.6 GNMA 210.5 — — — — — 210.5 Corporate securities — — — 65.1 10.0 5.0 80.1 Total $ 3,260.7 $ 92.8 $ 11.5 $ 65.1 $ 10.0 $ 13.6 $ 3,453.7 December 31, 2021 AAA AA A BBB Not Rated Total State, county, and municipal securities $ 17.2 $ 31.6 $ 14.7 $ — $ 4.1 $ 67.6 U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations FNMA/FHLMC 1,439.1 — — — — 1,439.1 GNMA 169.9 — — — — 169.9 Corporate securities — — 4.0 7.0 — 11.0 Total $ 1,626.2 $ 31.6 $ 18.7 $ 7.0 $ 4.1 $ 1,687.6 As of December 31, 2022 and 2021, the Company had $38.9 million and $16.6 million, respectively, of accrued interest receivable on the consolidated balance sheet. The Company does not consider accrued interest receivable in the carrying amount of financial assets held at the amortized cost basis or in the allowance for credit losses calculation. As of December 31, 2022 and 2021, there were no available-for-sale or held-to-maturity securities on nonaccrual status. All securities in the portfolio were current with their contractual principal and interest payments. As of December 31, 2022 and 2021, there were no collateral dependent available-for-sale or held-to-maturity securities. For the year ended December 31, 2022, there were $0.3 million in gross realized gains and $46.8 million in gross realized losses, primarily related to the sale of $500.0 million US treasury notes. The gross realized losses were offset by $22.1 million in deferred gains realized related to the termination of the fair value derivative of $46.3 million for a net realized loss on the termination of $24.2 million. For the year ended December 31, 2021, there were $3.2 million gross realized gains and $2.1 million gross realized losses. There were no material gross realized gains and no material gross realized losses for the year ended December 31, 2020. Maturities of securities do not reflect rate repricing opportunities present in adjustable-rate mortgage-backed securities. Maturities of mortgage-backed securities have been adjusted to reflect shorter maturities based upon estimated prepayments of principal. All other investment securities maturities are shown at contractual maturity dates. Available-for-Sale Held-to-Maturity December 31, 2022 Amortized Estimated Amortized Estimated Within one year $ 48.8 $ 48.1 $ 2.5 $ 2.5 After one year but within five years 1,478.9 1,419.8 607.6 581.6 After five years but within ten years 1,750.0 1,564.3 732.7 639.5 After ten years 4,295.8 3,913.9 2,110.9 1,828.6 Total $ 7,573.5 $ 6,946.1 $ 3,453.7 $ 3,052.2 As of December 31, 2022, the Company held investment securities callable within one year with amortized costs and estimated fair values of $1,443.3 million and $1,356.5 million, respectively. These investment securities are primarily classified as available-for-sale and included in the “after ten years category” in the table above. As of December 31, 2022, the Company had no callable structured notes. As of December 31, 2022 and 2021, the Company recorded amortized costs of $4,998.9 million and $2,617.8 million, respectively, for investment securities pledged to secure public deposits and securities sold under repurchase agreements and had approximate fair values as of December 31, 2022 and 2021 of $4,432.0 million and $2,610.8 million, respectively. All securities sold under repurchase agreements are with clients and mature on the next banking day. The Company retains possession of the underlying securities sold under repurchase agreements. As of December 31, 2022 and 2021, the Company held $198.6 million and $53.8 million, respectively, in equity securities in a combination of FRB and FHLB stocks, which are restricted nonmarketable securities acquired to meet regulatory requirements. These securities are carried at cost.

Loans Held for Sale

Loans Held for Sale	12 Months Ended
Loans Held for Sale	Dec. 31, 2022
Loans Held for Sale [Abstract]
Loans Held for Sale	The following table presents loans held for sale by segment for the dates indicated: December 31, December 31, Loans Held for Sale: Agricultural $ 62.5 $ — Commercial construction 10.5 — Residential real estate 6.9 30.1 Total loans held for sale $ 79.9 $ 30.1 On February 1, 2022, the Company acquired $2.1 million of held for sale residential real estate loans. In conjunction with the acquisition of GWB, the Company reclassified certain agricultural and commercial loans to loans held for sale from loans held for investment due to management’s intent and decision to sell the loans. The table below presents the non-residential held for sale loan activity for the 2022 period: Agricultural Commercial Construction Commercial Beginning balance $ — $ — $ — GWB loans held for investment transferred to loans held for sale on acquisition date 190.9 — 24.0 Loans held for sale transferred to loans held for investment (19.8) — — Repayments and discounted pay-offs (110.1) — (0.6) Loan disposals — — (23.4) Loans held for investment transferred to loans held for sale — 12.4 — Increase (decrease) in estimated fair value of the loans 1.5 (1.9) — Ending balance $ 62.5 $ 10.5 $ — As of December 31, 2022, loans held for sale included nonaccrual loans of $39.8 million, of which $29.3 million were agricultural loans and $10.5 million was a commercial construction loan. There were no loans held for sale that were considered a TDR as of December 31, 2022.

Loans Held for Investment

Loans Held for Investment	12 Months Ended
Loans Held for Investment	Dec. 31, 2022
Receivables [Abstract]
Loans	LOANS HELD FOR INVESTMENT The following table presents loans by segment as of the dates indicated: 2022 2021 Real estate loans: Commercial $ 8,528.6 $ 3,971.5 Construction loans: Land acquisition & development 386.2 247.8 Residential 516.2 262.0 Commercial 1,042.0 498.0 Total construction loans 1,944.4 1,007.8 Residential 2,188.3 1,538.2 Agricultural 794.9 213.9 Total real estate loans 13,456.2 6,731.4 Consumer loans: Indirect 829.7 737.6 Direct and advance lines 152.9 129.2 Credit card 75.9 64.9 Total consumer loans 1,058.5 931.7 Commercial 2,882.6 1,475.5 Agricultural 708.3 203.9 Other, including overdrafts 9.2 1.5 Loans held for investment 18,114.8 9,344.0 Deferred loan fees and costs (15.6) (12.3) Loans held for investment, net of deferred fees and costs 18,099.2 9,331.7 Allowance for credit losses (220.1) (122.3) Net loans held for investment $ 17,879.1 $ 9,209.4 Allowance for Credit Losses The following tables represent, by loan portfolio segment, the activity in the allowance for credit losses for loans held for investment: December 31, 2022 Beginning Balance ACL Recorded for PCD loans Provision for (reversal of) Credit Losses (2) Loans Charged-Off Recoveries Collected Ending Balance Allowance for credit losses (1) Real estate: Commercial real estate: Non-owner occupied $ 17.3 $ 17.2 $ (4.2) $ (3.5) $ 0.4 $ 27.2 Owner occupied 13.3 9.5 (2.7) (2.5) 1.9 19.5 Multi-family 13.3 10.9 8.7 (5.7) 0.7 27.9 Total commercial real estate 43.9 37.6 1.8 (11.7) 3.0 74.6 Construction: Land acquisition & development 0.5 3.4 (0.4) (2.6) 0.4 1.3 Residential construction 2.4 — 1.1 — 0.1 3.6 Commercial construction 6.0 0.2 31.6 (6.6) — 31.2 Total construction 8.9 3.6 32.3 (9.2) 0.5 36.1 Residential real estate: Residential 1-4 family 13.4 0.1 6.9 (0.2) 0.3 20.5 Home equity and HELOC 1.2 — — (0.1) 0.5 1.6 Total residential real estate 14.6 0.1 6.9 (0.3) 0.8 22.1 Agricultural real estate 1.9 2.3 1.5 (0.2) 0.4 5.9 Total real estate 69.3 43.6 42.5 (21.4) 4.7 138.7 Consumer: Indirect 14.3 — 2.7 (4.0) 2.3 15.3 Direct and advance lines 4.6 — 2.2 (3.7) 2.1 5.2 Credit card 2.2 — 2.4 (2.4) 0.6 2.8 Total consumer 21.1 — 7.3 (10.1) 5.0 23.3 Commercial: Commercial and floor plans 27.1 11.2 15.1 (6.6) 2.2 49.0 Commercial purpose secured by 1-4 family 4.4 0.2 1.2 (0.2) 0.1 5.7 Credit card 0.1 — 1.4 (1.3) — 0.2 Total commercial 31.6 11.4 17.7 (8.1) 2.3 54.9 Agricultural: Agricultural 0.3 4.5 0.9 (5.4) 2.9 3.2 Total agricultural 0.3 4.5 0.9 (5.4) 2.9 3.2 Total allowance for credit losses $ 122.3 $ 59.5 $ 68.4 $ (45.0) $ 14.9 $ 220.1 (1) Amounts presented are exclusive of the allowance for credit losses related to unfunded commitments which are included in Note “Financial Instruments with Off-Balance Sheet Risk” included in this report. (2) Amounts include $68.3 million related to the acquired GWB non-PCD loans. December 31, 2021 Beginning Balance Provision for (reversal of) Credit Loss Loans Charged-Off Recoveries Collected Ending Balance Allowance for credit losses (1) Real estate: Commercial real estate: Non-owner occupied $ 25.5 $ (8.3) $ — $ 0.1 $ 17.3 Owner occupied 18.3 (2.7) (2.3) — 13.3 Multi-family 11.0 2.3 — — 13.3 Total commercial real estate 54.8 (8.7) (2.3) 0.1 43.9 Construction: Land acquisition & development 1.3 (0.1) (1.2) 0.5 0.5 Residential construction 1.6 0.9 (0.1) — 2.4 Commercial construction 7.3 (1.3) (0.1) 0.1 6.0 Total construction 10.2 (0.5) (1.4) 0.6 8.9 Residential real estate: Residential 1-4 family 11.4 2.0 — — 13.4 Home equity and HELOC 1.4 (0.4) (0.1) 0.3 1.2 Total residential real estate 12.8 1.6 (0.1) 0.3 14.6 Agricultural real estate 2.7 (0.1) (0.7) — 1.9 Total real estate 80.5 (7.7) (4.5) 1.0 69.3 Consumer: Indirect 16.7 (1.4) (3.5) 2.5 14.3 Direct and advance lines 4.6 1.7 (2.9) 1.2 4.6 Credit card 2.6 0.6 (1.8) 0.8 2.2 Total consumer 23.9 0.9 (8.2) 4.5 21.1 Commercial: Commercial and floor plans 34.2 (7.3) (3.0) 3.2 27.1 Commercial purpose secured by 1-4 family 4.7 (0.5) (0.3) 0.5 4.4 Credit card 0.3 0.1 (0.4) 0.1 0.1 Total commercial 39.2 (7.7) (3.7) 3.8 31.6 Agricultural: Agricultural 0.7 (0.2) (0.2) — 0.3 Total agricultural 0.7 (0.2) (0.2) — 0.3 Total allowance for credit losses $ 144.3 $ (14.7) $ (16.6) $ 9.3 $ 122.3 (1) Amounts presented are exclusive of the allowance for credit losses related to unfunded commitments which are included in Note “Financial Instruments with Off-Balance Sheet Risk” included in this report. December 31, 2020 Beginning Balance Initial Impact of Adopting ASC 326 Provision for (reversal of) Credit Loss Loans Charged-Off Recoveries Collected Ending Balance Allowance for credit losses (1) Real estate: Commercial real estate: Non-owner occupied $ 8.8 $ 4.9 $ 11.7 $ — $ 0.1 $ 25.5 Owner occupied 10.0 3.5 5.0 (0.4) 0.2 18.3 Multi-family 0.7 6.9 3.4 — — 11.0 Total commercial real estate 19.5 15.3 20.1 (0.4) 0.3 54.8 Construction: Land acquisition & development 1.9 (0.1) (0.4) (0.5) 0.4 1.3 Residential construction 1.5 (0.9) 1.0 — — 1.6 Commercial construction 2.7 1.3 3.3 — — 7.3 Total construction 6.1 0.3 3.9 (0.5) 0.4 10.2 Residential real estate: Residential 1-4 family 1.8 10.6 (1.1) — 0.1 11.4 Home equity and HELOC 1.0 0.5 (0.4) — 0.3 1.4 Total residential real estate 2.8 11.1 (1.5) — 0.4 12.8 Agricultural real estate 0.5 1.8 0.4 — — 2.7 Total real estate 28.9 28.5 22.9 (0.9) 1.1 80.5 Consumer: Indirect 4.5 8.8 5.4 (4.1) 2.1 16.7 Direct and advance lines 2.9 3.0 1.6 (3.9) 1.0 4.6 Credit card 2.5 0.3 1.8 (2.8) 0.8 2.6 Total consumer 9.9 12.1 8.8 (10.8) 3.9 23.9 Commercial: Commercial and floor plans 25.5 (5.1) 20.4 (8.0) 1.4 34.2 Commercial purpose secured by 1-4 family 5.9 (3.8) 2.5 (0.1) 0.2 4.7 Credit card 1.2 (1.1) 1.1 (1.0) 0.1 0.3 Total commercial 32.6 (10.0) 24.0 (9.1) 1.7 39.2 Agricultural: Agricultural 1.6 (0.6) (0.2) (0.1) — 0.7 Total agricultural 1.6 (0.6) (0.2) (0.1) — 0.7 Total allowance for credit losses $ 73.0 $ 30.0 $ 55.5 $ (20.9) $ 6.7 $ 144.3 (1) Amounts presented are exclusive of the allowance for credit losses related to unfunded commitments which are included in Note “Financial Instruments with Off-Balance Sheet Risk” included in this report. Collateral-Dependent Loans Collateral-dependent loans rely solely on the operation or sale of the collateral for repayment. In evaluating the overall risk associated with a loan, the Company considers (1) character, overall financial condition and resources, and payment record of the borrower; (2) the prospects for support from any financially responsible guarantors; and (3) the nature and degree of protection provided by the cash flow and value of any underlying collateral. The loan may become collateral-dependent when the borrower is experiencing financial difficulty and, its sources of repayment become inadequate over time. At such time, the Company develops an expectation that repayment will be provided substantially through the operation or sale of the collateral. The following table presents the amortized cost basis of collateral-dependent loans by class of loans as of the dates indicated: As of December 31, 2022 As of December 31, 2021 Collateral Type Business Assets Real Property Other Total Business Assets Real Property Other Total Real estate $ 1.9 $ 25.3 $ — $ 27.2 $ 1.2 $ 7.0 $ — $ 8.2 Commercial 3.1 1.5 — 4.6 1.8 1.0 — 2.8 Agricultural 2.1 5.2 — 7.3 — 0.7 — 0.7 Total collateral-dependent $ 7.1 $ 32.0 $ — $ 39.1 $ 3.0 $ 8.7 $ — $ 11.7 Aging Analysis Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Loans classified in the following table as greater than 90 days past due continue to accrue interest. The following tables present the contractual aging of the Company’s recorded amortized cost basis in loans by portfolio as of the dates indicated. Total Loans 30 - 59 60 - 89 > 90 30 or More Days Days Days Days Current Non-accrual Total As of December 31, 2022 Past Due Past Due Past Due Past Due Loans Loans (1) Loans Real estate Commercial $ 5.6 $ 0.8 $ 1.1 $ 7.5 $ 8,501.5 $ 19.6 $ 8,528.6 Construction: Land acquisition & development 1.8 — 0.6 2.4 380.1 3.7 386.2 Residential 1.1 — — 1.1 515.1 — 516.2 Commercial 7.5 0.6 — 8.1 1,033.9 — 1,042.0 Total construction loans 10.4 0.6 0.6 11.6 1,929.1 3.7 1,944.4 Residential 9.9 2.1 1.2 13.2 2,168.7 6.4 2,188.3 Agricultural 1.1 6.1 — 7.2 780.1 7.6 794.9 Total real estate loans 27.0 9.6 2.9 39.5 13,379.4 37.3 13,456.2 Consumer: Indirect consumer 9.3 2.4 0.6 12.3 814.7 2.7 829.7 Other consumer 0.8 0.3 0.1 1.2 151.4 0.3 152.9 Credit card 0.8 0.4 0.6 1.8 74.1 — 75.9 Total consumer loans 10.9 3.1 1.3 15.3 1,040.2 3.0 1,058.5 Commercial 7.1 1.7 2.1 10.9 2,861.5 10.2 2,882.6 Agricultural 0.8 2.2 0.1 3.1 696.5 8.7 708.3 Other, including overdrafts — — — — 9.2 — 9.2 Loans held for investment $ 45.8 $ 16.6 $ 6.4 $ 68.8 $ 17,986.8 $ 59.2 $ 18,114.8 Total Loans 30 - 59 60 - 89 > 90 30 or More Days Days Days Days Current Non-accrual Total As of December 31, 2021 Past Due Past Due Past Due Past Due Loans Loans (1) Loans Real estate Commercial $ 1.1 $ 1.0 $ 0.6 $ 2.7 $ 3,960.8 $ 8.0 $ 3,971.5 Construction: Land acquisition & development 0.2 — — 0.2 246.9 0.7 247.8 Residential 4.2 — — 4.2 257.8 — 262.0 Commercial — — — — 498.0 — 498.0 Total construction loans 4.4 — — 4.4 1,002.7 0.7 1,007.8 Residential 3.0 0.8 0.1 3.9 1,531.4 2.9 1,538.2 Agricultural 1.9 0.2 — 2.1 206.9 4.9 213.9 Total real estate loans 10.4 2.0 0.7 13.1 6,701.8 16.5 6,731.4 Consumer: Indirect consumer 5.1 1.4 0.4 6.9 729.0 1.7 737.6 Other consumer 0.5 0.2 0.1 0.8 128.3 0.1 129.2 Credit card 0.6 0.2 0.5 1.3 63.6 — 64.9 Total consumer loans 6.2 1.8 1.0 9.0 920.9 1.8 931.7 Commercial 4.9 0.7 1.1 6.7 1,463.8 5.0 1,475.5 Agricultural 0.7 — — 0.7 201.6 1.6 203.9 Other, including overdrafts — — — — 1.5 — 1.5 Loans held for investment $ 22.2 $ 4.5 $ 2.8 $ 29.5 $ 9,289.6 $ 24.9 $ 9,344.0 (1) As of December 31, 2022 and 2021, none of our non-accrual loans were earning interest income. Additionally, no material interest income was recognized on non-accrual loans at December 31, 2022 and 2021, respectively and $1.5 million accrued interest was reversed at December 31, 2022. Troubled Debt Restructurings Modifications of performing loans are made in the ordinary course of business and are completed on a case-by-case basis through negotiation with the borrower in connection with the ongoing loan collection processes. Loan modifications are made to provide borrowers payment relief and typically include adjustments such as changes to interest rates, the implementation of interest only periods of less than twelve months, the deferment of short-term payments, and extension of amortization periods. A loan modification is considered a TDR if the borrower is experiencing financial difficulties and the Company, for economic or legal reasons, grants a concession to the borrower that it would not under other circumstances. Certain troubled loans are on non-accrual status at the time of debt restructuring. These restructured loans may be returned to accrual status if the borrower has exhibited sustained repayment performance in compliance with the restructuring agreement for a period of at least six months and the Company is reasonably assured of the borrower’s future performance. If the TDR meets these performance criteria, and the interest rate granted at the modification date is equal to or greater than the rate that the Company might grant for a new loan at the same time at comparable risk, then the loan will be reclassified to performing status and the accrual of interest will resume. Loans that return to performing status will continue to be evaluated individually for credit deterioration in the ordinary course of business. The 2020 Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) provided financial institutions with options on the treatment of TDRs, and the Company elected to apply these options at the individual loan level. Under the CARES Act, the Company could elect: (1) to suspend the requirements under GAAP for loan modifications related to the Coronavirus Disease 2019 (“COVID–19”) pandemic that would otherwise be categorized as a TDR; and/or (2) to suspend any determination of a loan modified as being a TDR as a result of the effects of the COVID–19 pandemic, including impairment for accounting purposes. If the Company elects a suspension noted above, the suspension (a) will be effective for the term of the loan modification, but solely with respect to any modification, including a forbearance arrangement, an interest rate modification, a repayment plan, and any other similar arrangement that defers or delays the payment of principal or interest, occurring for a loan that was not more than 30 days past due as of December 31, 2019; and (b) will not apply to any adverse impact on the credit of a borrower that is not related to the COVID–19 pandemic. These suspensions ended on January 2, 2022. The Company renegotiated loans in TDRs in the amount of $64.6 million as of December 31, 2022, of which $4.2 million were included in non-accrual loans and $60.4 million were on accrual status. As of December 31, 2022, the Company allocated $1.1 million of allowance for credit losses to those loans and the Company had no material commitments to lend additional funds to borrowers whose existing loans have been renegotiated or are classified as non-accrual. The Company renegotiated loans in TDRs in the amount of $6.2 million as of December 31, 2021, of which $3.9 million were included in non-accrual loans and $2.3 million were on accrual status. As of December 31, 2021, the Company allocated $0.1 million of allowance for credit losses to those loans and the Company had no material commitments to lend additional funds to borrowers whose existing loans have been renegotiated or are classified as non-accrual. The Company had $71.7 million of new TDRs during the period ended December 31, 2022 and no material new TDRs during the periods ending December 31, 2021 and 2020. The following table presents information of the Company’s TDRs that occurred for the period indicated: Number of Notes Type of Concession Principal Balance at Restructure December 31, 2022 Interest only period Extension of term or amortization schedule Interest rate adjustment Other (1) Commercial real estate 4 $ 3.2 $ 4.2 $ — $ 46.3 $ 53.7 Residential real estate 2 — 0.6 — — 0.6 Agriculture real estate 2 — 9.0 — — 9.0 Commercial 3 — 1.9 — 0.6 2.5 Agriculture 1 — — — 5.9 5.9 Total loans restructured during period 12 $ 3.2 $ 15.7 $ — $ 52.8 $ 71.7 (1) Other includes concessions that reduce or defer payments for a specified period of time and/or concessions that do not fit into other designated categories. For TDRs that were on non-accrual status or otherwise deemed collateral-dependent before a modification, the Company may record an allowance for credit losses depending on the circumstances. In periods after modification, the Company continues to evaluate all TDRs for possible credit deterioration and, where deterioration is observed, recognizes credit loss through the allowance. Additionally, the Company continues to work these loans through the credit cycle through charge-off, pay-off, or foreclosure. Financial effects of modifications of TDRs may include principal loan forgiveness or other charge-offs directly related to the restructuring. The Company had $5.7 million in charge-offs directly related to modifying an acquired PCD loan, for which a TDR was initiated during the period ending December 31, 2022. The Company had no charge-offs directly related to TDRs during the periods ending December 31, 2021, and 2020. The Company had no material TDRs resulting in payment default during the periods ending December 31, 2022, 2021, and 2020. The Company considers a payment default to occur on TDRs when the loan is 90 days or more past due or is placed on non-accrual status after the modification. During the period ending December 31, 2022, the Company modified the terms of certain other loans with a total recorded investment of $743.3 million where the loan did not meet the definition of a TDR and the borrowers had not been experiencing financial difficulties or there were delays in a payment considered to be insignificant. The Company determines whether a borrower is experiencing financial difficulty by evaluating the probability that the borrower will be in payment default on any of its debt in the foreseeable future without the modification as required under the Company’s internal underwriting policy. Purchased Credit Deteriorated Loans (PCD) The Company analyzes all acquired loans at the time of acquisition for more-than-insignificant deterioration in credit quality since their origination date. Such loans are classified as PCD, also referred to as PCD loans. Acquired loans classified as PCD are recorded at an initial amortized cost, which is comprised of the purchase price of the loans plus the initial allowance for credit losses for the loans, and any resulting discount or premium related to factors other than credit. The Company accounts for interest income on PCD loans using the interest method, whereby any purchase discounts or premiums are accreted or amortized into interest income as an adjustment of the loan’s yield. The following table reconciles the par value, or initial amortized cost, of PCD loans acquired in the GWB acquisition as of the date of the acquisition with the purchase price (or initial fair value of the loans) as amended for measurement period adjustments as of December 31, 2022: Purchase price (initial fair value) $ 623.3 Allowance for credit losses (1) 298.2 Discount attributable to other factors (2) 57.7 Par value (unpaid principal balance) $ 979.2 (1) For acquired PCD loans, an allowance of $298.2 million was required with a corresponding increase to the amortized cost basis as of the acquisition date. For PCD loans where all or a portion of the loan balance had been previously written-off by GWB, or would be subject to write-off under the Company’s charge-off policy, a CECL allowance of $238.7 million, included as part of the grossed-up loan balance at acquisition was immediately written-off. The net impact to the allowance for PCD assets on the acquisition date was $59.5 million. (2) Non-credit discount includes the difference between the amortized cost basis and the unpaid principal balance of $39.6 million established on GWB PCD loans acquired and interest applied to principal of $18.1 million. Credit Quality Indicators As part of the on-going and continuous monitoring of the credit quality of the Company’s loan portfolio, management tracks internally assigned risk classifications of loans based on relevant information about the ability of borrowers to service their debt. The factors considered by the Company include, among other factors, the borrower’s current financial information, historical payment experience, credit documentation, public information, and current economic trends. The Company analyzes loans individually to classify the credit risk of the loans. This analysis generally includes loans with an outstanding balance greater than $1.0 million, which are generally considered non-homogeneous loans, such as commercial loans and commercial real estate loans. This analysis is performed no less than on an annual basis, depending upon the size of exposure and the contractual obligations governing the borrower’s financial reporting frequency. Homogeneous loans, including small business loans, are typically managed by payment performance. The Company internally risk rates its loans in accordance with a Uniform Classification System developed jointly by the various bank regulatory agencies. The Uniform Classification System defines three broad categories of criticized assets, which the Company uses as credit quality indicators in addition to the 6 Pass ratings in its 10-point rating scale: Special Mention — includes loans that exhibit a potential weakness in financial condition, loan structure, or documentation that warrants management’s close attention. If not promptly corrected, the potential weaknesses may result in deterioration of the repayment prospects for the loan or of the institution’s credit position at some future date. Substandard — includes loans that are inadequately protected by the current net worth and paying capacity of the borrower which have well-defined weaknesses that jeopardize the liquidation of the debt. Although the primary source of repayment for a substandard loan may not currently be sufficient, collateral or other sources of repayment are sufficient to satisfy the debt. Continuance of a substandard loan is not warranted unless positive steps are taken to improve the worthiness of the credit. Doubtful — includes loans that exhibit pronounced weaknesses based on currently existing facts, conditions, and values to a point where collection or liquidation for full repayment is highly questionable and improbable. Doubtful loans are required to be placed on non-accrual status and are assigned specific loss exposure. Loans not meeting the criteria above that are analyzed individually as part of the above-described process are considered pass-rated loans. The Company evaluates the credit quality and loan performance for the allowance for credit loan losses of the following segments based on the aforementioned risk scale for the periods indicated: December 31, 2022 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2022 2021 2020 2019 2018 Prior Revolving Loans Amortized Cost Basis Total Commercial real estate non-owner occupied: Pass $ 1,162.6 $ 861.3 $ 661.1 $ 467.6 $ 241.5 $ 890.4 $ 29.2 $ 4,313.7 Special mention 1.0 6.8 2.3 4.6 — 7.4 — 22.1 Substandard 0.1 13.9 10.8 18.2 19.6 9.8 — 72.4 Total $ 1,163.7 $ 882.0 $ 674.2 $ 490.4 $ 261.1 $ 907.6 $ 29.2 $ 4,408.2 Commercial real estate owner occupied: Pass $ 793.0 $ 718.7 $ 533.9 $ 266.3 $ 165.8 $ 551.3 $ 18.2 $ 3,047.2 Special mention 10.9 14.2 12.3 6.1 5.6 5.5 1.1 55.7 Substandard 8.4 3.0 2.3 8.9 8.5 17.2 0.5 48.8 Doubtful 0.4 1.4 — — — — — 1.8 Total $ 812.7 $ 737.3 $ 548.5 $ 281.3 $ 179.9 $ 574.0 $ 19.8 $ 3,153.5 Commercial multi-family: Pass $ 369.2 $ 204.9 $ 189.0 $ 52.1 $ 35.0 $ 113.7 $ 1.0 $ 964.9 Special mention — — — — — 1.7 — 1.7 Substandard — — — — — 0.3 — 0.3 Total $ 369.2 $ 204.9 $ 189.0 $ 52.1 $ 35.0 $ 115.7 $ 1.0 $ 966.9 Land, acquisition and development: Pass $ 152.5 $ 114.4 $ 29.5 $ 17.0 $ 10.9 $ 28.4 $ 22.2 $ 374.9 Special mention 6.7 — — — 0.2 0.3 — 7.2 Substandard — 0.3 0.2 — — 0.4 — 0.9 Doubtful — 3.2 — — — — — 3.2 Total $ 159.2 $ 117.9 $ 29.7 $ 17.0 $ 11.1 $ 29.1 $ 22.2 $ 386.2 Residential construction: Pass $ 118.4 $ 119.9 $ 0.4 $ 0.3 $ 0.4 $ 5.8 $ 270.1 $ 515.3 Substandard — 0.5 — — — 0.4 — 0.9 Total $ 118.4 $ 120.4 $ 0.4 $ 0.3 $ 0.4 $ 6.2 $ 270.1 $ 516.2 Commercial construction: Pass $ 442.7 $ 374.8 $ 89.7 $ 45.9 $ 0.4 $ — $ 10.6 $ 964.1 Special mention 2.3 — 23.1 — — — 11.3 36.7 Substandard 16.8 24.4 — — — — — 41.2 Total $ 461.8 $ 399.2 $ 112.8 $ 45.9 $ 0.4 $ — $ 21.9 $ 1,042.0 Agricultural real estate: Pass $ 180.0 $ 172.8 $ 109.5 $ 64.8 $ 46.6 $ 105.1 $ 31.4 $ 710.2 Special mention 22.4 0.7 1.2 2.6 10.0 3.2 11.0 51.1 Substandard 1.8 12.3 3.5 0.6 2.7 11.3 0.1 32.3 Doubtful — — 1.3 — — — — 1.3 Total $ 204.2 $ 185.8 $ 115.5 $ 68.0 $ 59.3 $ 119.6 $ 42.5 $ 794.9 Commercial and floor plans: Pass $ 501.7 $ 358.9 $ 214.4 $ 124.3 $ 120.3 $ 171.1 $ 631.6 $ 2,122.3 Special mention 15.9 6.8 1.3 4.4 0.9 4.9 18.5 52.7 Substandard 9.8 3.3 3.7 3.4 3.2 2.1 47.2 72.7 Doubtful 0.3 1.3 — — — — 0.1 1.7 Total $ 527.7 $ 370.3 $ 219.4 $ 132.1 $ 124.4 $ 178.1 $ 697.4 $ 2,249.4 December 31, 2022 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2022 2021 2020 2019 2018 Prior Revolving Loans Amortized Cost Basis Total Commercial purpose secured by 1-4 family: Pass $ 191.7 $ 134.5 $ 69.8 $ 30.4 $ 29.9 $ 39.5 $ 28.9 $ 524.7 Special mention 0.1 1.2 2.1 0.2 1.4 0.2 — 5.2 Substandard 0.2 0.3 0.1 0.3 0.9 1.2 — 3.0 Total $ 192.0 $ 136.0 $ 72.0 $ 30.9 $ 32.2 $ 40.9 $ 28.9 $ 532.9 Agricultural: Pass $ 127.2 $ 59.7 $ 31.8 $ 10.6 $ 8.6 $ 3.1 $ 375.1 $ 616.1 Special mention 26.1 2.8 0.4 1.0 0.3 — 26.2 56.8 Substandard 22.8 4.6 2.8 0.6 1.2 0.2 0.8 33.0 Doubtful — 0.5 — — — — — 0.5 Total $ 176.1 $ 67.6 $ 35.0 $ 12.2 $ 10.1 $ 3.3 $ 402.1 $ 706.4 December 31, 2021 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2021 2020 2019 2018 2017 Prior Revolving Loans Amortized Cost Basis Total Commercial real estate non-owner occupied: Pass $ 507.9 $ 452.2 $ 237.9 $ 150.4 $ 76.3 $ 409.0 $ 15.3 $ 1,849.0 Special mention 0.2 3.1 2.1 — — 3.6 — 9.0 Substandard 3.9 15.3 2.3 0.7 1.0 12.4 — 35.6 Total $ 512.0 $ 470.6 $ 242.3 $ 151.1 $ 77.3 $ 425.0 $ 15.3 $ 1,893.6 Commercial real estate owner occupied: Pass $ 452.7 $ 314.9 $ 235.0 $ 151.0 $ 94.5 $ 322.5 $ 14.2 $ 1,584.8 Special mention 1.3 3.2 1.5 7.4 3.5 13.8 — 30.7 Substandard 3.8 4.3 4.7 5.4 2.7 20.3 — 41.2 Total $ 457.8 $ 322.4 $ 241.2 $ 163.8 $ 100.7 $ 356.6 $ 14.2 $ 1,656.7 Commercial multi-family: Pass $ 129.1 $ 118.6 $ 43.9 $ 15.4 $ 36.0 $ 76.7 $ 1.5 $ 421.2 Total $ 129.1 $ 118.6 $ 43.9 $ 15.4 $ 36.0 $ 76.7 $ 1.5 $ 421.2 Land, acquisition and development: Pass $ 113.0 $ 41.5 $ 34.2 $ 14.8 $ 19.8 $ 20.8 $ 1.2 $ 245.3 Special mention — 0.1 — — 0.1 0.3 — 0.5 Substandard 0.8 0.2 — 0.6 0.3 0.1 — 2.0 Total $ 113.8 $ 41.8 $ 34.2 $ 15.4 $ 20.2 $ 21.2 $ 1.2 $ 247.8 Residential construction: Pass $ 112.4 $ 7.0 $ 13.7 $ 0.9 $ — $ — $ 127.2 $ 261.2 Substandard — 0.4 — — 0.4 — — 0.8 Total $ 112.4 $ 7.4 $ 13.7 $ 0.9 $ 0.4 $ — $ 127.2 $ 262.0 Commercial construction: Pass $ 209.7 $ 141.4 $ 118.8 $ 27.6 $ — $ 0.5 $ — $ 498.0 Total $ 209.7 $ 141.4 $ 118.8 $ 27.6 $ — $ 0.5 $ — $ 498.0 Agricultural real estate: Pass $ 58.3 $ 36.9 $ 35.1 $ 22.6 $ 11.8 $ 28.1 $ 4.9 $ 197.7 Special mention 0.1 1.3 1.2 0.1 0.1 0.9 0.9 4.6 Substandard 4.0 0.4 1.0 0.6 1.3 4.3 — 11.6 Total $ 62.4 $ 38.6 $ 37.3 $ 23.3 $ 13.2 $ 33.3 $ 5.8 $ 213.9 December 31, 2021 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2021 2020 2019 2018 2017 Prior Revolving Loans Amortized Cost Basis Total Commercial and floor plans: Pass $ 394.2 $ 165.7 $ 94.5 $ 73.5 $ 47.1 $ 91.3 $ 224.7 $ 1,091.0 Special mention 0.8 11.4 0.8 0.8 3.0 2.3 7.0 26.1 Substandard 1.3 2.8 1.6 2.6 0.6 4.1 2.6 15.6 Total $ 396.3 $ 179.9 $ 96.9 $ 76.9 $ 50.7 $ 97.7 $ 234.3 $ 1,132.7 Commercial purpose secured by 1-4 family: Pass $ 94.9 $ 55.0 $ 27.8 $ 23.1 $ 15.3 $ 32.2 $ 14.4 $ 262.7 Special mention — 0.2 0.2 0.5 0.1 0.6 — 1.6 Substandard 1.3 1.2 0.6 0.6 0.2 1.3 0.1 5.3 Total $ 96.2 $ 56.4 $ 28.6 $ 24.2 $ 15.6 $ 34.1 $ 14.5 $ 269.6 Agricultural: Pass $ 35.1 $ 16.2 $ 9.0 $ 5.4 $ 2.1 $ 1.6 $ 108.9 $ 178.3 Special mention 0.2 4.1 0.1 0.4 0.6 0.3 7.0 12.7 Substandard 4.9 0.7 0.6 2.5 — 0.1 2.6 11.4 Total $ 40.2 $ 21.0 $ 9.7 $ 8.3 $ 2.7 $ 2.0 $ 118.5 $ 202.4 The Company evaluates the credit quality, loan performance, and the allowance for credit losses of its residential and consumer loan portfolios based primarily on the aging status of the loan and borrower payment activity. Accordingly, loans on nonaccrual status, loans past due 90 days or more and still accruing interest, and loans modified under TDRs are considered nonperforming for purposes of credit quality evaluation. The following tables present the recorded investment of our other loan portfolios based on the credit risk profile of loans that are performing and loans that are nonperforming as of the periods indicated: As of December 31, 2022 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2022 2021 2020 2019 2018 Prior Revolving Loans Amortized Cost Basis Total Residential 1-4 family: Performing $ 258.9 $ 490.3 $ 541.6 $ 98.0 $ 32.0 $ 213.8 $ — $ 1,634.6 Nonperforming — 0.2 0.1 0.5 0.3 3.7 — 4.8 Total $ 258.9 $ 490.5 $ 541.7 $ 98.5 $ 32.3 $ 217.5 $ — $ 1,639.4 Consumer home equity and HELOC: Performing $ 23.8 $ 8.0 $ 5.2 $ 5.5 $ 5.6 $ 15.2 $ 482.8 $ 546.1 Nonperforming 0.6 0.3 0.2 0.2 0.1 1.2 0.2 2.8 Total $ 24.4 $ 8.3 $ 5.4 $ 5.7 $ 5.7 $ 16.4 $ 483.0 $ 548.9 Consumer indirect: Performing $ 380.3 $ 176.4 $ 130.0 $ 59.7 $ 33.6 $ 46.3 $ — $ 826.3 Nonperforming 1.0 0.9 0.6 0.3 0.2 0.4 — 3.4 Total $ 381.3 $ 177.3 $ 130.6 $ 60.0 $ 33.8 $ 46.7 $ — $ 829.7 Consumer direct and advance line: Performing $ 52.6 $ 31.9 $ 18.2 $ 8.5 $ 6.5 $ 8.9 $ 25.8 $ 152.4 Nonperforming 0.1 0.1 0.1 — — 0.1 0.1 0.5 Total $ 52.7 $ 32.0 $ 18.3 $ 8.5 $ 6.5 $ 9.0 $ 25.9 $ 152.9 As of December 31, 2021 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2021 2020 2019 2018 2017 Prior Revolving Loans Amortized Cost Basis Total Residential 1-4 family: Performing $ 360.9 $ 477.0 $ 74.7 $ 27.5 $ 25.7 $ 176.5 $ — $ 1,142.3 Nonperforming — 0.3 — — 0.2 0.8 — 1.3 Total $ 360.9 $ 477.3 $ 74.7 $ 27.5 $ 25.9 $ 177.3 $ — $ 1,143.6 Consumer home equity and HELOC: Performing $ 11.1 $ 7.0 $ 3.7 $ 4.8 $ 3.6 $ 12.0 $ 350.7 $ 392.9 Nonperforming 0.3 — 0.3 — 0.6 0.5 — 1.7 Total $ 11.4 $ 7.0 $ 4.0 $ 4.8 $ 4.2 $ 12.5 $ 350.7 $ 394.6 Consumer indirect: Performing $ 272.6 $ 208.6 $ 108.3 $ 64.0 $ 37.0 $ 45.0 $ — $ 735.5 Nonperforming 0.5 0.5 0.4 0.2 0.1 0.4 — 2.1 Total $ 273.1 $ 209.1 $ 108.7 $ 64.2 $ 37.1 $ 45.4 $ — $ 737.6 Consumer direct and advance line: Performing $ 42.5 $ 27.9 $ 15.0 $ 13.3 $ 5.8 $ 7.6 $ 16.9 $ 129.0 Nonperforming 0.1 — — 0.1 — — — 0.2 Total $ 42.6 $ 27.9 $ 15.0 $ 13.4 $ 5.8 $ 7.6 $ 16.9 $ 129.2 While the Company considers the performance of the loan portfolio on the allowance for credit losses, for certain credit card loan classes, the Company also evaluates credit quality based on the aging status of the loan, which was previously presented, and by payment activity of the credit card holder. The following table presents the recorded investment in credit card loans based on payment activity for the periods indicated: As of December 31, 2022 Consumer Commercial Agricultural Total Credit Card: Performing $ 75.4 $ 100.0 $ 1.9 $ 177.3 Nonperforming 0.5 0.3 — 0.8 Total credit card $ 75.9 $ 100.3 $ 1.9 $ 178.1 As of December 31, 2021 Consumer Commercial Agricultural Total Credit Card: Performing $ 64.4 $ 73.1 $ 1.5 $ 139.0 Nonperforming 0.5 0.1 — 0.6 Total credit card $ 64.9 $ 73.2 $ 1.5 $ 139.6

Premises and Equipment

Premises and Equipment	12 Months Ended
Premises and Equipment	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Premises and Equipment	PREMISES AND EQUIPMENT Premises and equipment and related accumulated depreciation are as follows: December 31, 2022 2021 Land $ 86.7 $ 52.0 Buildings and improvements 469.2 346.8 Furniture and equipment 111.0 97.0 Total premises and equipment 666.9 495.8 Less accumulated depreciation (222.2) (196.2) Premises and equipment, net $ 444.7 $ 299.6 Depreciation expense was $35.1 million, $28.0 million, and $25.8 million for the years ended December 31, 2022, 2021, and 2020, respectively. The Parent Company and a FIB branch office lease premises from an affiliated entity. See Note —Commitments and Contingencies.

Company-Owned Life Insurance

Company-Owned Life Insurance	12 Months Ended
Company-Owned Life Insurance	Dec. 31, 2022
Investments, All Other Investments [Abstract]
Company-Owned Life Insurance	COMPANY-OWNED LIFE INSURANCE Company-owned life insurance consists of the following: December 31, 2022 2021 Key executive, principal shareholder $ 3.2 $ 3.2 Key executive split dollar 7.1 7.1 Group life 487.6 291.2 Total $ 497.9 $ 301.5 The Company maintains key executive life insurance policies on certain principal shareholders. Under these policies, the Company receives benefits payable upon the death of the insured. The net cash surrender value of key executive, principal shareholder insurance policies was $3.2 million at December 31, 2022 and 2021. The Company also has life insurance policies covering selected other key officers. The net cash surrender value of these policies was $7.1 million at December 31, 2022 and 2021. Under these policies, the Company receives benefits payable upon death of the insured. An endorsement split dollar agreement has been executed with the selected key officers whereby a portion of the policy death benefit is payable to their designated beneficiaries. The endorsement split dollar agreement will provide post-retirement coverage for those selected key officers meeting specified retirement qualifications. The Company expenses the earned portion of the post-employment benefit through the vesting period.

Other Real Estate Owned

Other Real Estate Owned	12 Months Ended
Other Real Estate Owned	Dec. 31, 2022
Repossessed Assets [Abstract]
Other Real Estate Owned	OTHER REAL ESTATE OWNED Information with respect to the Company’s other real estate owned follows: Year Ended December 31, 2022 2021 2020 Balance at beginning of year $ 2.0 $ 2.5 $ 8.5 OREO acquired through acquisitions 15.8 — — Additions 0.4 0.9 3.3 Valuation adjustments (2.8) — (0.1) Dispositions (2.7) (1.4) (9.2) Balance at end of year $ 12.7 $ 2.0 $ 2.5 There were $2.8 million of write-downs during 2022, which were adjustments based on internal evaluations and other sources, including management estimates of the current fair value of properties, and adjustments directly related to receipt of updated appraisals. There were no material write-downs during 2021 or 2020. The carrying value of foreclosed residential real estate properties included in OREO was not material as of December 31, 2022 and 2021. The Company had no material recorded investments in consumer mortgage loans secured by residential real estate for which formal foreclosure proceedings were in process of foreclosure as of December 31, 2022 and 2021.

Derivatives and Hedging Activit

Derivatives and Hedging Activities	12 Months Ended
Derivatives and Hedging Activities	Dec. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities	DERIVATIVES AND HEDGING ACTIVITIES The Company is exposed to certain risks arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through the management of its business activities. The Company manages economic risks, including interest rate, liquidity, and credit risk primarily by managing the amount, sources, and duration of its assets and liabilities and through the use of derivative financial instruments. The Company enters into derivative financial instruments, such as interest rate swap contracts to manage or hedge exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates and interest rate exposures. The Company does not enter into interest rate swap agreements for trading or speculative purposes. In the normal course of business, the Company enters into interest rate lock commitments to finance residential mortgage loans that are not designated as accounting hedges. These commitments, which contain fixed expiration dates, offer the borrower an interest rate guarantee, provided the loan meets underwriting guidelines, and closes within the timeframe established by the Company. Interest rate risk arises on these commitments and subsequently on closed loans if interest rates change between the time of the interest rate lock and the delivery of the loan to the investor. Loan commitments related to residential mortgage loans intended to be sold are considered derivatives and are marked to market through earnings. In addition to the effects of the change in market interest rate, the fair value measurement of the derivative also contemplates the expected cash flows to be received from the counterparty from the future sale of the loan. The Company sells residential mortgage loans on either a best efforts or mandatory delivery basis. The Company mitigates the effect of the interest rate risk inherent in providing interest rate lock commitments by entering into forward loan sales contracts. The forward loan sales contracts are marked to market through earnings and are not designated as accounting hedges during the interest rate lock commitment period and through the duration of the forward loan sales contracts. Exclusive of the fair value component associated with the projected cash flows from the loan delivery to the investor, the changes in fair value related to movements in market rates of the interest rate lock commitments and the forward loan sales contracts generally move in opposite directions, and the net impact of changes in these valuations on net income during the loan commitment period is generally inconsequential. When the loan is funded to the borrower, the interest rate lock commitment derivative expires, and the Company records a loan held for sale. The forward loan sales contract acts as a hedge against the variability in cash to be received from the loan sale. The changes in measurement of the estimated fair values of the interest rate lock commitments and forward loan sales contracts are included in mortgage banking revenues in the accompanying consolidated statements of income. The Company also enters into certain interest rate swap contracts that are not designated as hedging instruments. These derivative contracts relate to transactions in which the Company enters into an interest rate swap with a client while at the same time entering into an offsetting interest rate swap with a third-party financial institution. Because the Company acts as an intermediary for the client, changes in the fair value of the underlying derivative contracts for the most part offset each other and do not significantly impact the Company’s results of operations. Cash Flow Hedges of Interest Rate Risk The Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the Company primarily uses interest rate swaps and collars as part of its interest rate risk management strategy. Interest rate swaps that were designated as cash flow hedges on the trust preferred securities involve the receipt of variable amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. During 2021 and the first quarter of 2022, such derivatives were used to hedge the variable cash flows associated with the existing variable-rate borrowings (trust preferred securities). The trades that the Company had in place on its trust preferred securities matured during the first and second quarters of 2022. As part of the Company’s overall asset and liability management strategy, in August 2022, the Company entered into two interest rate collars related to variable-rate loans that were designated as cash flow hedges with a total notional amount of $300.0 million. The collars designated as cash flow hedges synthetically fix the interest income received by the Company when the collar index falls below a floor rate on a rate reset during the term of the collar and when the collar index exceeds the cap rate on a rate reset during the term of the collar without exchange of the underlying notional amount. In October 2022, the Company entered into four forward starting receive-fixed hedges related to pools of variable-rate loans and securities that were designated as cash flow hedges with a total notional amount of $850.0 million. The swaps designated as cash flow hedges synthetically fix the interest income received by the Company once they become effective. For derivatives designated and that qualify as cash flow hedges of interest rate risk, the gain or loss on the derivative is recorded in accumulated other comprehensive (loss) income and subsequently reclassified into interest expense in the same period(s) during which the hedged transaction affects earnings. Amounts reported in accumulated other comprehensive (loss) income related to derivatives will be reclassified as interest expense when interest payments are made on the Company’s variable-rate liabilities. During the next twelve months, the Company estimates that $5.4 million will be reclassified to interest income. Fair Value Hedges of Interest Rate Risk The Company is exposed to changes in the fair value of fixed-rate assets due to changes in benchmark interest rates. The Company uses interest rate swaps to manage its exposure to changes in fair value on these instruments attributable to changes in the designated benchmark interest rate. Interest rate swaps designated as fair value hedges involve the payment of fixed-rate amounts to a counterparty in exchange for the Company receiving variable-rate payments over the life of the agreements without the exchange of the underlying notional amount. During 2021, the Company entered into two forward starting, fixed interest rate fair value hedges associated with U.S. Treasury securities. During the second quarter of 2022, the Company terminated the $500.0 million, two-year forward starting, three-year pay-fixed interest rate swap, resulting in a $23.3 million gain. The gain associated with the $500.0 million interest rate swap was to be accreted into income through May 2026. However, the U.S. Treasury securities associated with the swap were sold during the fourth quarter of 2022. As such, the gain was accreted through August 2022 and then in September 2022 the remaining gain was recognized as income. During the third quarter of 2022, the Company terminated the $200.0 million, three-year forward starting, four-year pay fixed interest rate swap, resulting in a $8.5 million gain that will be accreted into income through July 2028. For derivatives designated and that qualify as fair value hedges, the gain or loss on the derivative as well as the offsetting loss or gain on the hedged item attributable to the hedged risk are recognized in interest income. The following amounts were recorded on the balance sheet related to cumulative basis adjustment for fair value hedges for the periods indicated: December 31, 2022 December 31, 2021 Carrying Amount of the Hedged Assets/(Liabilities) Cumulative Amount of Fair Value Hedging Adjustment Carrying Amount of the Hedged Assets/(Liabilities) Cumulative Amount of Fair Value Hedging Adjustment Available-for-sale securities $ 191.9 $ 8.1 $ 695.6 $ (4.4) Non-designated Hedges Derivatives not designated as hedges are not speculative and result from a service the Company provides to certain customers. The Company executes interest rate swaps with commercial banking customers to facilitate their respective risk management strategies. Those interest rate swaps are simultaneously hedged by offsetting derivatives that the Company executes with a third party, such that the Company minimizes its net risk exposure resulting from such transactions. As the interest rate derivatives associated with this program do not meet the strict hedge accounting requirements, changes in the fair value of both the customer derivatives and the offsetting derivatives are recognized directly in earnings. Risk Participation Agreements The Company acquired from GWB risk participation agreements under which it assumes credit risk associated with a borrower’s performance related to derivative contracts. The Company only enters into these credit risk participation agreements in instances in which the Company is also a party to the related loan participation agreements for such borrowers. The Company manages its credit risk under risk participation agreements by monitoring the creditworthiness of the borrower, based on its normal credit review process. The following table summarizes the fair values of our derivative instruments on a gross and net basis for the periods indicated. The derivative asset and liability balances are presented on a gross basis, prior to the application of bilateral collateral and master netting agreements, but after the variation margin payments with central clearing organizations have been applied as settlement, as applicable. Total derivative assets and liabilities are adjusted to account for the impact of legally enforceable master netting agreements that allow us to settle all derivative contracts with a single counterparty on a net basis and to offset the net derivative position with the related cash collateral. Securities collateral related to legally enforceable master netting agreements is not offset on the balance sheet. December 31, 2022 December 31, 2021 Notional Amount Balance Sheet Location Estimated Notional Amount Balance Sheet Location Estimated Derivatives designated as hedges: Interest rate swap contracts $ 550.0 $ 3.5 $ 700.0 $ 4.1 Derivatives not designated as hedges: Interest rate swap contracts 1,728.1 41.6 913.9 22.2 Interest rate lock commitments — — 77.3 1.8 Forward loan sales contracts 12.6 0.1 — — Derivative assets in the balance sheet $ 2,290.7 Other Assets $ 45.2 $ 1,691.2 Other Assets $ 28.1 Derivatives designated as hedges: Interest rate collars $ 300.0 $ 5.4 $ — $ — Interest rate swap contracts 300.0 0.3 87.6 0.1 Derivatives not designated as hedges: Interest rate swap contracts 1,728.1 153.9 913.9 18.1 Risk participation agreements 106.1 — — — Interest rate lock commitments 14.8 — — — Forward loan sales contracts — — 102.4 — Derivative liabilities in the balance sheet $ 2,449.0 Accrued Expenses $ 159.6 $ 1,103.9 Accrued Expenses $ 18.2 As of December 31, 2022 there was $2.2 million of net unrealized fair value loss on derivative instruments in accumulated other comprehensive loss. There were no material effects of derivative instruments in fair value or cash flow hedge accounting on accumulated other comprehensive (loss) income during the period ended December 31, 2021. There were no material effects from the Company’s fair value or cash flow hedged derivative financial instruments on the income statement during the periods ended December 31, 2022 or 2021. The table below presents the effect of the Company’s derivative financial instruments that are not designated as hedging instruments on the income statement for the periods indicated: December 31, 2022 2021 Location of Gain or (Loss) Recognized in Income on Derivative Amount of Gain or (Loss) Recognized in Income on Derivative Interest rate lock commitments Mortgage banking revenues $ (1.7) $ (0.5) The Company recorded swap fee revenues of $5.9 million and $3.1 million for the years ended December 31, 2022 and 2021, respectively. The Company includes swap fee revenues in other service charges, commissions, and fees. The tables below present the gross presentation, the effects of offsetting, and a net presentation of the Company’s derivatives as of the periods indicated: December 31, 2022 Gross Assets Recognized Gross Assets Offset in the Balance Sheet Net Assets in the Balance Sheet Financial Instruments Cash Collateral Received Net Amount Interest rate swap and collar contracts $ 45.1 $ — $ 45.1 $ — $ 45.1 $ — Forward loan sales contracts 0.1 — 0.1 — — 0.1 Total derivatives 45.2 — 45.2 — 45.1 0.1 Total assets $ 45.2 $ — $ 45.2 $ — $ 45.1 $ 0.1 Gross Liabilities Recognized Gross Liabilities Offset in the Balance Sheet Net Liabilities in the Balance Sheet Financial Instruments Cash Collateral Posted Net Amount Interest rate swap and collar contracts $ 159.6 $ — $ 159.6 $ — $ — $ 159.6 Risk participation agreements — — — — — — Forward loan sales contracts — — — — — — Total derivatives 159.6 — 159.6 — — 159.6 Repurchase agreements 1,052.9 — 1,052.9 — 1,052.9 — Total liabilities $ 1,212.5 $ — $ 1,212.5 $ — $ 1,052.9 $ 159.6 December 31, 2021 Gross Assets Recognized Gross Assets Offset in the Balance Sheet Net Assets in the Balance Sheet Financial Instruments Cash Collateral Received Net Amount Interest rate swap contracts $ 26.3 $ — $ 26.3 $ — $ 8.0 $ 18.3 Mortgage related derivatives 1.8 — 1.8 — — 1.8 Total derivatives 28.1 — 28.1 — 8.0 20.1 Total assets $ 28.1 $ — $ 28.1 $ — $ 8.0 $ 20.1 Gross Liabilities Recognized Gross Liabilities Offset in the Balance Sheet Net Liabilities in the Balance Sheet Financial Instruments Cash Collateral Posted Net Amount Interest rate swap contracts $ 18.2 $ — $ 18.2 $ — $ — $ 18.2 Total derivatives 18.2 — 18.2 — — 18.2 Repurchase agreements 1,051.1 — 1,051.1 — 1,051.1 — Total liabilities $ 1,069.3 $ — $ 1,069.3 $ — $ 1,051.1 $ 18.2 Credit-risk-related Contingent Feature The Company has agreements with each of its derivative counterparties that contain a provision where if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then the Company could also be declared in default on its derivative obligations. The Company has agreements with certain of its derivative counterparties that contain a provision where if the Company fails to maintain its status as a well / adequately capitalized institution, then in certain instances the Company could be required to post additional capital and in certain instances the counterparty would have the right to terminate the derivative positions and the Company would be required to settle its obligations under the agreements. As of December 31, 2022, the fair value of derivatives in a net liability position, which includes accrued interest but excludes any adjustment for nonperformance risk, was zero related to these agreements. As of December 31, 2022, the Company has minimum collateral posting thresholds with certain of its derivative counterparties and has not posted excess collateral. If the Company had breached any of these provisions at December 31, 2022, it could have been required to settle its obligations under the agreements at their termination value.

Mortgage Servicing Rights

Mortgage Servicing Rights	12 Months Ended
Mortgage Servicing Rights	Dec. 31, 2022
Transfers and Servicing [Abstract]
Mortgage Servicing Rights	MORTGAGE SERVICING RIGHTS Information with respect to the Company’s mortgage servicing rights follows: Year Ended December 31, 2022 2021 2020 Balance at beginning of year $ 31.6 $ 34.3 $ 30.6 Acquisition of mortgage servicing rights 1.3 — — Originations of mortgage servicing rights 2.5 3.7 11.7 Amortization expense (4.3) (6.4) (8.0) Balance at end of year 31.1 31.6 34.3 Less valuation reserve — (3.4) (10.3) Balance at end of year, net of valuation reserve $ 31.1 $ 28.2 $ 24.0 Principal balance of serviced loans underlying mortgage servicing rights $ 3,259.8 $ 3,203.7 $ 3,585.5 Mortgage servicing rights as a percentage of serviced loans 0.95 % 0.88 % 0.67 %

Deposits

Deposits	12 Months Ended
Deposits	Dec. 31, 2022
Deposits [Abstract]
Deposits	DEPOSITS Deposits are summarized as follows: December 31, 2022 2021 Non-interest bearing demand $ 7,560.0 $ 5,568.3 Interest bearing: Demand 7,205.9 4,753.2 Savings 8,379.3 4,981.6 Time, $250 and over 438.0 186.7 Time, other 1,490.4 779.8 Total interest bearing 17,513.6 10,701.3 Total deposits $ 25,073.6 $ 16,269.6 Other time deposits include time deposits under $250,000 and deposits obtained through the Company’s participation in the Certificate of Deposit Account Registry Service (“CDARS”). CDARS deposits totaled $36.6 million and $104.5 million as of December 31, 2022 and 2021, respectively. The Company had no brokered deposits as of December 31, 2022 and 2021, respectively As of December 31, 2022 and 2021, the Company had time deposits of $438.0 million and $186.7 million, respectively, that met or exceeded the FDIC insurance limit of $250,000. Maturities of time deposits at December 31, 2022 are as follows: Time, $250 Total Time Due within 3 months or less $ 47.8 $ 311.8 Due after 3 months and within 6 months 34.6 215.4 Due after 6 months and within 12 months 283.9 1,005.4 Due within 2024 55.0 282.8 Due within 2025 10.7 69.2 Due within 2026 4.8 27.8 Due within 2027 and thereafter 1.2 16.0 Total $ 438.0 $ 1,928.4

Long-Term Debt and Other Borrow

Long-Term Debt and Other Borrowed Funds	12 Months Ended
Long-Term Debt and Other Borrowed Funds	Dec. 31, 2022
Debt Disclosure [Abstract]
Long-Term Debt and Other Borrowed Funds	LONG-TERM DEBT AND OTHER BORROWED FUNDS A summary of long-term debt follows: December 31, 2022 2021 Parent Company: Fixed to floating subordinated notes, 5.25% fixed rate effective May 2020 through May 2025 $ 98.9 $ 98.7 Subsidiaries: 8.00% finance lease obligation with term ending October 25, 2029 1.0 1.0 2.28% note payable maturing July 29, 2022, principal due at maturity, interest payable monthly — 5.0 1.00% note payable maturing December 31, 2041, interest only payable quarterly until December 31, 2025 and then principal and interest until maturity 5.1 5.1 Note payable maturing March 31, 2038, interest only payable at 1.30% monthly until March 31, 2025 and then principal and interest at 3.25% until maturity 2.0 2.0 1.30% note payable maturing June 1, 2034, interest only payable monthly until March 31, 2025 and then principal and interest until maturity 0.6 0.6 1.12% note payable maturing December 31, 2045, interest only payable annually until December 31, 2028 and then principal and interest until maturity 6.8 — 1.35% note payable maturing December 31, 2046 interest only payable annually until December 31, 2025 and then principal and interest until maturity 6.4 — Total long-term debt $ 120.8 $ 112.4 Maturities of long-term debt at December 31, 2022 were as follows: 2023 $ 0.1 2024 0.1 2025 0.1 2026 0.1 2027 0.2 Thereafter 120.2 Total $ 120.8 On May 15, 2020, the Company completed a public offering of $100.0 million fixed-to-floating rate subordinated notes due May 15, 2030 (the “Notes”). The debt is included in Tier 2 capital for the Company. The Company may elect to redeem the Notes, in whole or in part, on any early redemption date which is any interest payment date on or after May 15, 2025 at a redemption price equal to 100% of the principal amount plus any accrued and unpaid interest. The Company may also redeem the Notes, in whole but not in part, upon certain conditions as defined in the indenture agreement. Any early redemption of the Notes will be subject to regulatory approval. From and including the date of issuance to, but excluding, May 15, 2025, or earlier redemption date, the Notes bear interest at an initial fixed rate of 5.25% per annum, payable semi-annually in arrears on May 15 and November 15 of each year, which commenced on November 15, 2020. From and including May 15, 2025 to, but excluding, May 15, 2025, or earlier redemption date, the Notes will bear interest at a floating rate per annum equal to a benchmark rate, which is expected to be Three-Month Term SOFR (as defined in the Indenture Agreement), plus 518.0 basis points, payable quarterly in arrears on February 15, May 15, August 15 and November 15 of each year, commencing on August 15, 2025. Unamortized debt issuance costs of $1.1 million, as of December 31, 2022, are being amortized to maturity. Subordinated debt is presented net of issuance costs on the consolidated balance sheet. The Notes are unsecured, subordinated obligations of the Company and: (i) rank junior to all of the Company’s existing and future senior indebtedness; (ii) rank equal in right of payment with any of the Company’s existing and future subordinated indebtedness; (iii) rank senior to the Company’s obligations relating to any junior subordinated debt securities issued to its capital trust subsidiaries; (iv) are effectively subordinated to all of the Company’s secured indebtedness to the extent of the value of the assets securing such indebtedness; and (v) are structurally subordinated to all of the existing and future liabilities and obligations of the Company’s subsidiaries, including deposit liabilities and claims of other creditors of the Company’s bank subsidiary, First Interstate Bank. Proceeds from the private placement of subordinated notes were used for general corporate purposes. The Company has a financing lease obligation on a banking office. Assets acquired under the financing lease, consist solely of a building and leasehold improvements, and are included in premises and equipment subject to depreciation. Additionally, the Company borrowed or assumed through acquisitions $20.9 million and $12.7 million as of December 31, 2022 and 2021, respectively, related to New Market Tax Credits. The long-term debt obligations consists of fixed rate note payables with various interest rates from 1.00% to 3.25% and maturities from September 6, 2032 through December 31, 2046, collateralized by the Company’s equity interest in various CDEs, which are 99.9% owned by the Company. As of December 31, 2022, the Company had $2,327.0 million in outstanding FHLB borrowings consisting of $827.0 million in 4.60% variable rate overnight borrowings and $1,500.0 million in 4.48% fixed rate borrowings in tenors up to one-month, as compared to no outstanding borrowings from the FHLB at December 31, 2021. The Company has remaining available lines of credit with the FHLB of approximately $2,441.0 million, subject to collateral availability at December 31, 2022. The borrowings are collateralized by certain loans with an advance equivalent collateral value of $4,768.0 million. As of December 31, 2022 and 2021, there were no long or short-term advances outstanding with the FHLB. As of December 31, 2022 and 2021, the Company had no material other borrowed funds. The Company has unused federal fund lines of credit with third parties amounting to $235.0 million, subject to funds availability. These lines are subject to cancellation without notice. The Company also has an unused line of credit with the FRB for borrowings up to $763.3 million secured by a blanket pledge of agricultural and commercial loans, and has an unused $100.0 million revolving line of credit with another third party.

Subordinated Debentures Held by

Subordinated Debentures Held by Subsidiary Trusts	12 Months Ended
Subordinated Debentures Held by Subsidiary Trusts	Dec. 31, 2022
Subordinated Borrowings [Abstract]
Subordinated Debentures Held by Subsidiary Trusts	SUBORDINATED DEBENTURES HELD BY SUBSIDIARY TRUSTSThe Company sponsors fourteen wholly-owned business trusts, Trust I through Trust XIV (collectively, the “Trusts”). The Trusts were formed for the exclusive purpose of issuing an aggregate of $163.1 million of 30-year floating rate mandatorily redeemable capital trust preferred securities (“Trust Preferred Securities”) to third-party investors. The Trusts also issued, in aggregate, $5.3 million of common equity securities to the Parent Company. Proceeds from the issuance of the Trust Preferred Securities and common equity securities were invested in 30-year junior subordinated deferrable interest debentures (“Subordinated Debentures”) issued by the Parent Company. A summary of Subordinated Debenture issuances follows: December 31, 2022 December 31, 2021 Issuance Interest Rate 1 Maturity Date Amount Common Shares 2 Amount Common Shares 2 Trust I November 2007 7.52% December 15, 2037 $ 15.5 $ 0.5 $ 15.5 $ 0.5 Trust II October 2007 5.99% January 1, 2038 10.3 0.3 10.3 0.3 Trust III December 2007 7.17% December 15, 2037 20.6 0.6 20.6 0.6 Trust IV December 2007 6.44% April 1, 2038 15.5 0.5 15.5 0.5 Trust V January 2008 6.49% April 1, 2038 10.3 0.3 10.3 0.3 Trust VI January 2008 6.49% April 1, 2038 10.3 0.3 10.3 0.3 Trust VII June 2005 6.43% June 30, 2035 5.2 0.2 5.2 0.2 Trust VIII March 2006 6.25% March 15, 2036 30.9 0.9 — — Trust IX June 2005 6.62% June 15, 2035 2.1 0.1 — — Trust X December 2003 7.59% December 17, 2033 23.1 0.7 — — Trust XI December 2002 7.43% January 7, 2033 5.2 0.2 — — Trust XII September 2003 7.18% October 8, 2033 7.2 0.2 — — Trust XIII December 2006 6.59% March 1, 2037 5.3 0.3 — — Trust XIV July 2007 5.39% October 1, 2037 2.2 0.2 — — Total subordinated debentures payable 163.7 $ 5.3 87.7 $ 2.7 Less: fair value adjustment 3 (0.6) (0.7) Total subordinated debentures payable, net of fair value adjustments $ 163.1 $ 87.0 1 Interest rates as of December 31, 2022 2 Common shares on subordinated debentures are included in other assets on the consolidated balance sheets 3 Adjustment reflects the fair value adjustments related to the subordinated deferrable interest debentures assumed as part of the Northwest and Great Western acquisitions. Trust I Subordinated Debentures issued by the Company bore interest at a fixed rate of 7.50% for five years after issuance until December 15, 2012, and thereafter at a variable rate equal to three-month LIBOR plus 2.75% per annum. Trust II Subordinated Debentures issued by the Company bear a cumulative floating interest rate equal to LIBOR plus 2.25% per annum. Trust III Subordinated Debentures issued by the Company bore interest at a fixed rate of 6.88% for five years after issuance until December 15, 2012, and thereafter at a variable rate equal to three-month LIBOR plus 2.40% per annum. Trust IV Subordinated Debentures issued by the Company bear a cumulative floating interest rate equal to three-month LIBOR plus 2.70% per annum. Trust V Subordinated Debentures issued by the Company bore interest at a fixed rate of 6.78% for five years after issuance until April 1, 2013, and thereafter at a variable rate equal to three-month LIBOR plus 2.75% per annum. Trust VI Subordinated Debentures issued by the Company bear a cumulative floating interest rate equal to three-month LIBOR plus 2.75% per annum. The Subordinated Debentures are unsecured with interest distributions payable quarterly. The Company may defer the payment of interest at any time provided that the deferral period does not extend past the stated maturity. During any such deferral period, distributions on the Trust Preferred Securities will also be deferred and the Company’s ability to pay dividends on its common and preferred shares is restricted. The Subordinated Debentures may be redeemed, subject to approval by the FRB, at the Company’s option on or after five years from the date of issue, or at any time in the event of unfavorable changes in laws or regulations. Debt issuance costs consisting primarily of underwriting discounts and professional fees were capitalized and are being amortized through maturity to interest expense using the straight-line method, which approximates level yield. The terms of the Trust Preferred Securities are identical to those of the Subordinated Debentures. The Trust Preferred Securities are subject to mandatory redemption upon repayment of the Subordinated Debentures at their stated maturity dates or earlier redemption in an amount equal to their liquidation amount plus accumulated and unpaid distributions to the date of redemption. The Company guarantees the payment of distributions and payments for redemption or liquidation of the Trust Preferred Securities to the extent of funds held by the Trusts. In conjunction with the acquisition of Northwest in August 2018, the Company acquired Northwest Bancorporation Capital Trust I (“Trust VII”). The Northwest Trust was formed for the exclusive purpose of issuing an aggregate of $5.0 million of 30-year floating rate mandatorily redeemable capital trust preferred securities (“Northwest Trust Preferred Securities”) to third-party investors. The Trusts also issued, in aggregate, $0.2 million of common equity securities to Northwest. Proceeds from the issuance of the Trust Preferred Securities and common equity securities were invested in 30-year junior subordinated deferrable interest debentures (“Northwest Subordinated Debentures”) issued by Northwest. The Subordinated Debentures bore interest at a fixed rate of 5.95% for five years after issuance until June 30, 2010, and thereafter at a variable rate equal to LIBOR plus 1.70% per annum. The Company acquired the GWB Capital Trust VI (“Trust VIII”) with the acquisition of Great Western in February 2022. Great Western caused to be issued 30,000 shares, $1,000 par value, or $30.0 million of preferred securities of Trust VIII on March 10, 2006, through a private placement. Trust VIII also issued, in aggregate, $0.9 million of common equity securities to Great Western. The distribution rate is set quarterly at three-month LIBOR plus 1.48%. Interest payment dates are December 15, March 15, June 15, and September 15 of each year, beginning June 15, 2006, and are payable in arrears. Proceeds from the issue were used for general corporate purposes including redemption of Great Western’s Preferred Securities of GWB Capital Trust II. The Company acquired the Sunstate Banchares Trust II (Trust IX”) with the acquisition of Great Western in February 2022. Sunstate Bancshares caused to be issued 2,000 shares, $1,000 par value, or $2.0 million of preferred securities of Trust IX on June 1, 2005, through a private placement. Trust IX also issued, in aggregate, $0.1 million of common equity securities to Sunstate Banchsares. The distribution rate is set quarterly at three-month LIBOR plus 1.85%. Interest payment dates are March 15, June 15, September 15, and December 15 of each year, beginning September 15, 2005, and are payable in arrears. The Company acquired the Great Western Statutory Trust IV (“Trust X”) with the acquisition of Great Western in February 2022. Great Western caused to be issued 22,400 shares, $1,000 par value, or $22.4 million of preferred securities of Trust X on December 17, 2003, through a private placement. Trust X also issued, in aggregate, $0.7 million of common equity securities to Great Western. The distribution rate is set quarterly at three-month LIBOR plus 2.85% basis points. Interest payment dates are March 17, June 17, September 17 and December 17 of each year, beginning March 17, 2004 and are payable in arrears. Proceeds from the issue were used for general corporate purposes. The Company acquired the HF Financial Capital Trust III (“Trust XI”) in the acquisition of Great Western in February 2022. HF Financial Corp. caused to be issued 5,000 shares, $1,000 par value, or $5.0 million of preferred securities of Trust XI on December 19, 2002, through a private placement. Trust XI also issued, in aggregate, $0.2 million of common equity securities to HF Financial Corp. The distribution rate is set quarterly at three-month LIBOR plus 3.35%. Interest payment dates are January 7, April 7, July 7, and October 7 of each year, beginning April 7, 2003, and are payable in arrears. The Company acquired the HF Trust IV (“Trust XII”) in the acquisition of Great Western in February 2022. HF Financial Corp. caused to be issued 7,000 shares, $1,000 par value, or $7.0 million of preferred securities of Trust XII on September 25, 2003, through a private placement. Trust XII also issued, in aggregate, $0.2 million of common equity securities to HF Financial Corp. The distribution rate is set quarterly at three-month LIBOR plus 3.10%. Interest payment dates are January 8, April 8, July 8, and October 8 of each year, beginning January 8, 2004, and are payable in arrears. The Company acquired the HF Trust V (“Trust XIII”) in the acquisition of Great Western in February 2022. HF Financial Corp. caused to be issued 5,000 shares, $1,000 par value, or $5.0 million of preferred securities of Trust XIII on December 7, 2006, through a private placement. Trust XIII also issued, in aggregate, $0.3 million of common equity securities to HF Financial Corp. The distribution rate is set quarterly at three-month LIBOR plus 1.83%. Interest payment dates are March 1, June 1, September 1, and December 1 of each year, beginning March 1, 2007, and are payable in arrears. In the first quarter of Great Western’s fiscal year 2017, Great Western redeemed 5,000 shares of Trust XIII debentures under the First Supplemental Indenture dated May 13, 2016. The Company acquired the HF Trust VI (“Trust XIV”) in the acquisition of Great Western in February 2022. HF Financial Corp. caused to be issued 2,000 shares, $1,000 par value, or $2.0 million of preferred securities of Trust XIV on July 5, 2007, through a private placement. Trust XIV also issued, in aggregate, $0.2 million of common equity securities to HF Financial Corp. The distribution rate is set quarterly at three-month LIBOR plus 1.65%. Interest payment dates are January 1, April 1, July 1, and October 1 of each year, beginning October 1, 2007, and are payable in arrears. For the seven Subordinated Debentures acquired from Great Western, the Company may, at one or more times, defer interest payments on the related debentures for up to 20 consecutive quarters following suspension of dividends on all capital stock. At the end of any deferral period, all accumulated and unpaid interest must be paid. Subject to the Company receiving prior approval of the Federal Reserve, if required, the Company has the right to redeem the debentures at the redemption price, in whole or in part, on an interest payment date. The redemption price is $1,000 per preferred security plus any accrued and unpaid interest to the date of redemption. Holders of the preferred securities have no voting rights. The preferred securities are unsecured and rank junior in priority of payment to all of the Company’s senior indebtedness and senior to the Company’s common and preferred stock. As of December 31, 2022, the Trust Preferred Securities qualified as tier 2 capital of the Parent Company under the Federal Reserve Board’s capital adequacy guidelines.

Capital Stock and Dividend Rest

Capital Stock and Dividend Restrictions	12 Months Ended
Capital Stock and Dividend Restrictions	Dec. 31, 2022
Equity [Abstract]
Capital Stock and Dividend Restrictions	CAPITAL STOCK AND DIVIDEND RESTRICTIONS As of December 31, 2022, the Company’s authorized common stock consists of 250,000,000 shares, of which, 150,000,000 shares are designated as Class A common stock, and 100,000,000 are designated as Class B common stock. There are no shares of Class B common stock outstanding. Our common stock is uncertificated. The Class A common stock has one vote per share. The Company had 104,442,023 shares of Class A common stock common stock outstanding as of December 31, 2022. The Company had 41,699,409 shares of Class A common stock and 20,501,047 shares of Class B common stock outstanding as of December 31, 2021. On February 1, 2022, the Company issued 46,879,601 shares of its Class A common stock with an aggregate value of approximately $1.7 billion as consideration for the acquisition of Great Western. Additionally, during 2022, the Company issued 33,769 shares of its Class A common stock with an aggregate value of $1.3 million to directors for their service on the Company’s board of directors during 2022. During 2021, the Company issued 19,081 shares of its Class A common stock with an aggregate value of $0.9 million to directors for their service on the Company’s board of directors during 2021. The aggregate value of the shares issued to directors is included in stock-based compensation expense in the accompanying consolidated statements of changes in stockholders’ equity. On March 25, 2022, all outstanding shares of the Company’s Class B common stock automatically converted into shares of the Company’s Class A common stock on a one-for-one basis, pursuant to the terms of the Company’s Third Amended and Restated Articles of Incorporation, as amended (the “Charter”). No additional shares of Class B common stock are permitted to be issued. The conversion occurred automatically pursuant to the Company’s Charter because the number of the Company’s outstanding shares of Class B common stock represented on March 25, 2022, the record date for determining the shareholders of the Company entitled to notice of, and to vote at, the Company’s 2022 Annual Meeting of Shareholders, was less than twenty percent (20%) of the aggregate number of all of the outstanding shares of Class A common stock and Class B common stock of the Company. The former holders of Class B common stock now hold Class A common stock with the same voting powers, preferences, rights and qualifications, limitations and restrictions as the other holders of Class A common stock. All shares of the Company’s outstanding capital stock are now composed solely of shares of Class A common stock and are entitled to one vote per share. The Company’s Class A common stock will continue to trade on the NASDAQ Stock Market under the ticker symbol “FIBK”. On May 25, 2022, the Company’s board of directors adopted a new stock repurchase program to replace the program that had been in place since 2019 and had 1,889,158 shares of Class A common stock remaining to be purchased thereunder. Under the new stock repurchase program, the Company may repurchase up to 5.0 million of its outstanding shares of Class A common stock. During 2022, the Company repurchased and retired 5.0 million shares under the stock repurchase program at a total cost of $197.4 million, including costs and commissions, at an average per share cost of $39.48. During 2021, the Company repurchased and retired 72,700 shares of Class A common stock under the it’s previously existing stock repurchase program. All other stock repurchases during 2022 and 2021 were redemptions of vested restricted shares tendered in lieu of cash for payment of income tax withholding amounts by participants in the Company’s equity compensation plans. On November 4, 2021, the Company filed a registration statement on Form S-4, as amended on December 14, 2021 with registration statement on Form S-4/A, to register 47,158,390 shares of Class A common stock to be issued as consideration for our acquisition of Great Western. On March 16, 2020, the Company filed a universal shelf registration statement on Form S-3, which was subsequently declared effective by the SEC. The shelf registration statement allows the Company to raise additional capital from time to time through offers and sales of registered securities consisting of debt securities, preferred stock, depository shares, common stock, warrants, purchase contracts, and units or units consisting of any combination of the foregoing securities. The Company may sell these securities using the prospectus in the shelf registration statement, together with applicable prospectus supplements, from time to time, in one or more offerings.

Earnings per Common Share

Earnings per Common Share	12 Months Ended
Earnings per Common Share	Dec. 31, 2022
Earnings Per Share [Abstract]
Earnings per Common Share	EARNINGS PER COMMON SHARE Basic earnings per common share is calculated by dividing net income by the weighted average number of common shares outstanding during the period presented, excluding unvested restricted stock. Diluted earnings per share is calculated by dividing net income by the weighted average number of common shares determined for the basic earnings per share computation plus the dilutive effects of stock-based compensation using the treasury stock method. The following table sets forth the computation of basic and diluted earnings per common share: Year Ended December 31, 2022 2021 2020 Net income, basic and diluted $ 202.2 $ 192.1 $ 161.2 Weighted average common shares outstanding for basic earnings per share computation 103,274,070 61,650,312 63,611,891 Dilutive effects of stock-based compensation 66,929 91,516 117,579 Weighted average common shares outstanding for diluted earnings per common share computation 103,340,999 61,741,828 63,729,470 Basic earnings per common share $ 1.96 $ 3.12 $ 2.53 Diluted earnings per common share 1.96 3.11 2.53

Regulatory Capital

Regulatory Capital	12 Months Ended
Regulatory Capital	Dec. 31, 2022
Banking Regulation, Risk-Based Information [Abstract]
Regulatory Capital	REGULATORY CAPITALThe Company and the Bank are subject to various regulatory capital requirements administered by federal banking regulators, including the Federal Reserve. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Company’s and the Bank’s financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Company and the Bank must meet specific capital guidelines that involve quantitative measures of the Company’s and Bank’s assets, liabilities and certain off-balance sheet items as calculated under regulatory accounting practices. The Parent Company, like all bank holding companies, is not subject to the prompt corrective action provisions. The Company’s and the Bank’s capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings and other factors. Quantitative measures established by regulation to ensure capital adequacy require the Company to maintain minimum amounts and ratios of total and tier 1 capital to risk-weighted assets, and of tier 1 capital to average assets, as defined in the regulations. As of December 31, 2022, the Company exceeded all capital adequacy requirements to which it is subject. As of December 31, 2022, the most recent notification from the regulatory agencies categorized the Bank as well capitalized under the regulatory framework for prompt corrective action. To be categorized as well-capitalized, the institution must maintain minimum total risk-based, Tier 1 risk-based, and Tier 1 leverage ratios as set forth in the following table. There are no conditions or events since the most recent notification that management believes have changed the Bank's categories. As an approved mortgage seller, the Bank is required to maintain a minimum level of capital specified by the United States Department of Housing and Urban Development. At December 31, 2022 and 2021, the Bank met these requirements. The Company’s actual capital amounts and ratios and selected minimum regulatory thresholds and prompt corrective action provisions as of December 31, 2022 and 2021 are presented in the following tables: Actual Minimum Required for Capital Adequacy Purposes For Capital Adequacy Purposes Plus Capital Conservation Buffer Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements (1) December 31, 2022 Amount Ratio Amount Ratio Amount Ratio Amount Ratio Total risk-based capital: Consolidated $ 2,875.8 12.48 % $ 1,843.2 8.00 % $ 2,419.2 10.50 % $ 2,304.0 10.00 % FIB 2,713.5 11.80 1,839.6 8.00 2,414.5 10.50 2,299.5 10.00 Tier 1 risk-based capital: Consolidated 2,408.8 10.45 1,382.4 6.00 1,958.4 8.50 1,843.2 8.00 FIB 2,504.1 10.89 1,379.7 6.00 1,954.6 8.50 1,839.6 8.00 Common equity tier 1 risk-based capital: Consolidated 2,408.8 10.45 1,036.8 4.50 1,612.8 7.00 1,497.6 6.50 FIB 2,504.1 10.89 1,034.8 4.50 1,609.7 7.00 1,494.7 6.50 Leverage capital ratio: Consolidated 2,408.8 7.75 1,242.9 4.00 1,242.9 4.00 1,553.6 5.00 FIB 2,504.1 8.07 1,241.1 4.00 1,241.1 4.00 1,551.4 5.00 December 31, 2021 Amount Ratio Amount Ratio Amount Ratio Amount Ratio Total risk-based capital: Consolidated $ 1,659.3 14.11 % $ 940.9 8.00 % $ 1,235.0 10.50 % $ 1,176.2 10.00 % FIB 1,472.5 12.56 938.0 8.00 1,231.1 10.50 1,172.5 10.00 Tier 1 risk-based capital: Consolidated 1,469.0 12.49 705.7 6.00 999.7 8.50 940.9 8.00 FIB 1,382.2 11.79 703.5 6.00 996.6 8.50 938.0 8.00 Common equity tier 1 risk-based capital: Consolidated 1,384.8 11.77 529.3 4.50 823.3 7.00 764.5 6.50 FIB 1,382.2 11.79 527.6 4.50 820.8 7.00 762.1 6.50 Leverage capital ratio: Consolidated 1,469.0 7.68 765.5 4.00 765.5 4.00 956.9 5.00 FIB 1,382.2 7.24 764.1 4.00 764.1 4.00 955.1 5.00 (1) The ratios for the well capitalized requirement are only applicable to FIB. However, the Company manages its capital position as if the requirement applies to the consolidated entity and has presented the ratios as if they also applied on a consolidated basis.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES The Company had commitments under construction contracts of $1.8 million as of December 31, 2022. The Parent Company and the Billings office of FIB are the anchor tenants in a building owned by an entity in which FIB has a 50.0% ownership interest. The Company leases certain premises and equipment from third parties under operating leases. Total rental expense to third parties was $8.9 million, $4.3 million, and $5.1 million, in 2022, 2021, and 2020, respectively. The total future minimum rental commitments, exclusive of maintenance and operating costs, required under operating leases that have initial or remaining noncancelable lease terms in excess of one year at December 31, 2022, are as follows: Third Parties Related Entity Total For the year ending December 31: 2023 $ 10.1 $ 1.4 $ 11.5 2024 9.1 1.4 10.5 2025 7.7 1.4 9.1 2026 6.5 0.9 7.4 2027 4.7 0.1 4.8 Thereafter 10.6 — 10.6 Total $ 48.7 $ 5.2 $ 53.9 Residential mortgage loans sold to investors in the secondary market are sold with varying recourse provisions. Essentially all the loan sales agreements require the repurchase of a mortgage loan by the seller in situations such as breach of representation, warranty, or covenant; untimely document delivery; false or misleading statements; failure to obtain certain certificates or insurance; or unmarketability. Certain loan sales agreements contain repurchase requirements based on payment-related defects that are defined in terms of the number of days or months since the purchase, the sequence number of the payment, and/or the number of days of payment delinquency. Based on the specific terms stated in the agreements, the Company had $0.9 million and $0.4 million of sold residential mortgage loans with recourse provisions still in effect as of December 31, 2022 and 2021, respectively. The Company did not repurchase a significant amount of loans from secondary market investors under the terms of loan sales agreements during the years ended December 31, 2022, 2021, and 2020. In the opinion of management, the risk of recourse and the subsequent requirement of loan repurchase to the Company is not significant, and accordingly no liabilities have been established related to such. In addition, the Company made various representations and warranties associated with the sale of loans. The Company has not incurred significant losses resulting from these provisions. A substantial portion of the Company’s clients’ ability to honor their contracts is dependent on the economy in Arizona, Colorado, Idaho, Iowa, Kansas, Minnesota, Missouri, Montana, Nebraska, North Dakota, Oregon, South Dakota, Washington, and Wyoming. The Company’s loan portfolio is diversified and assigned to risk classifications by industry concentrations and the current economic conditions. These industry concentrations of credit are taken into consideration by management in determining the allowance for credit losses. In the normal course of business, the Company is involved in various other claims and litigation. In the opinion of management, following consultation with legal counsel, the ultimate liability or disposition thereof is not expected to have a material adverse effect on the consolidated financial condition, results of operations, or liquidity of the Company.

Financial Instruments with Off-

Financial Instruments with Off-Balance Sheet Risk	12 Months Ended
Financial Instruments with Off-Balance Sheet Risk	Dec. 31, 2022
Financial Instruments with Off-Balance Sheet Risk [Abstract]
Financial Instruments with Off-Balance Sheet Risk	FINANCIAL INSTRUMENTS WITH OFF-BALANCE SHEET RISK In the normal course of business, the Company is a party to financial instruments with off-balance sheet risk to meet the financing needs of its clients. These financial instruments include commitments to extend credit and standby letters of credit. These instruments involve, to varying degrees, elements of credit and interest rate risk in excess of amounts recorded in the consolidated balance sheets. Commitments to extend credit are agreements to lend to a client as long as there is no violation of any condition established in the commitment contract. Since many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. Standby letters of credit are conditional commitments issued by the Company to guarantee the performance of a client to a third party. The credit risk involved in issuing letters of credit is essentially the same as that involved in extending loan facilities to clients. The Company’s policy for obtaining collateral, and determining the nature of such collateral, is essentially the same as in the Company’s policies for making commitments to extend credit. The estimated fair value of the obligation undertaken by the Company in issuing standby letters of credit is included in accounts payable and accrued expenses in the Company’s consolidated balance sheets. The following table presents our financial instruments with off-balance sheet risk, as well as the activity in the allowance for off-balance sheet credit losses related to those financial instruments: December 31, December 31, Beginning balance $ 3.8 $ 3.7 Provision for credit loss expense 12.4 0.1 Ending balance of allowance for off-balance sheet credit losses $ 16.2 $ 3.8 December 31, December 31, Unused credit card lines $ 827.6 $ 681.6 Commitments to extend credit 5,173.3 2,539.8 Standby letters of credit 93.8 57.5

Income Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Income tax expense consists of the following: Year ended December 31, 2022 2021 2020 Current: Federal $ 45.2 $ 39.4 $ 42.4 State 14.4 11.3 12.3 Total current 59.6 50.7 54.7 Deferred: Federal (3.7) 3.7 (5.7) State (1.0) 1.3 (0.9) Total deferred (4.7) 5.0 (6.6) Total income tax expense $ 54.9 $ 55.7 $ 48.1 Total income tax provision differs from the amount of income tax determined by applying the statutory federal income tax rate of 21% for the periods presented to income before income taxes due to the following: Year ended December 31, 2022 2021 2020 Tax expense at the statutory tax rate $ 54.0 $ 52.0 $ 44.0 Increase (decrease) in tax resulting from: Tax-exempt income (8.4) (2.8) (2.1) State income tax, net of federal income tax benefit 10.6 9.9 9.0 Deficiency (benefit) of stock-based compensation plans 0.2 (0.5) (0.4) Nondeductible transaction costs 2.0 0.8 — Federal tax credits (4.3) (4.3) (2.3) Other, net 0.8 0.6 (0.1) Tax expense at effective tax rate $ 54.9 $ 55.7 $ 48.1 The tax effects of temporary differences between the financial statement carrying amounts and tax bases of assets and liabilities that give rise to significant portions of the net deferred tax asset (liability) relate to the following: December 31, 2022 2021 Deferred tax assets: Loans, principally due to allowance for credit losses $ 54.8 $ 30.7 Loan discount 32.5 1.6 Investment securities, unrealized losses 157.9 4.6 Derivatives, unrealized losses 0.5 — Deferred compensation 26.8 19.3 Non-performing loan interest 2.6 1.0 Other real estate owned write-downs and carrying costs 1.5 — Net operating loss carryforwards (1) 1.5 1.7 Lease liabilities 12.0 8.7 Other reserves 8.8 — Contract incentives 8.5 — Discount on acquired investment securities 13.4 — Other 2.4 3.5 Deferred tax assets $ 323.2 $ 71.1 December 31, 2022 2021 Deferred tax liabilities: Fixed assets, principally differences in bases and depreciation $ (17.3) $ (7.7) Deferred loan costs (3.3) (1.9) Derivatives, unrealized gains — (1.0) Investment in joint venture partnership, principally due to differences in depreciation of partnership assets (1.3) (0.9) Right of use assets (11.3) (8.3) Prepaid amounts (0.9) (0.7) Government agency stock dividends (1.2) (1.2) Goodwill and other intangibles (68.2) (51.2) Mortgage servicing rights (7.4) (6.8) Other (1.8) (0.7) Deferred tax liabilities (112.7) (80.4) Net deferred tax assets (liabilities) $ 210.5 $ (9.3) (1) As of December 31, 2022, we had remaining federal net operating loss carryforwards of $2.7 million from acquired companies, which is available to offset federal taxable income and state net operating loss carryforwards in amounts which vary by state. The federal net operating losses will expire beginning in 2030 and ending in 2036 and the state net operating losses will expire beginning in 2023 and ending in 2034. The use of these carryforwards is subject to annual limitations. The Company had current net income tax receivables of $38.3 million and $16.1 million at December 31, 2022 and 2021, respectively.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
Stock-Based Compensation	Dec. 31, 2022
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION The Company has equity awards outstanding under the 2015 Equity Incentive Plan (the “2015 Plan”). The plan was primarily established to enhance the Company’s ability to attract, retain, and motivate employees. The Company’s Board of Directors or, upon delegation, the Compensation and Human Capital Committee of the Board of Directors (“Compensation Human Capital Committee”) has exclusive authority to select employees, advisors and others, including directors, to receive awards and to establish the terms and conditions of each award made pursuant to the Company’s stock-based compensation plan. The 2015 Plan, approved by the Company’s shareholders in May 2015, was established to provide the Company with flexibility to select from various equity-based performance compensation methods, and to be able to address changing accounting and tax rules and corporate governance practices by optimally utilizing performance based compensation. At December 31, 2022, there were 361,605 common shares available for future grant under the 2015 Plan. Stock Options. All options granted had an exercise price equal to fair market value, which was defined as the closing sales price for the stock as quoted on the NASDAQ Stock Market for the last market trading day preceding the date that the Company’s Board of Directors awards the benefit. Options were subject to vesting as determined by the Company’s Board of Directors or Compensation and Human Capital Committee, and could be exercised for periods of up to ten years from the date of grant. No stock option awards were granted in 2022 or 2021. All outstanding stock option awards were fully vested as of December 31, 2016. As such, there was no compensation expense or related income tax benefits recognized related to stock option awards in 2022 or 2021. Compensation expense related to stock option awards and the related income tax benefits for the year ended December 31, 2016 were not considered material. The following table summarizes stock option activity under the Company’s stock option plan: Year Ended December 31, 2022 Number of Weighted-Average Weighted-Average Outstanding options, beginning of year 23,252 $ 14.37 Exercised (22,684) 14.37 Forfeited (568) 14.37 Outstanding options, end of year — $ — 0.00 Outstanding options exercisable, end of year — $ — 0.00 The were no stock options outstanding as of December 31, 2022. The total intrinsic value of options exercised was $0.6 million, $1.5 million, and $3.1 million during the years ended December 31, 2022, 2021, and 2020, respectively. The actual tax benefit realized for the tax deduction from option exercises totaled $0.1 million, $0.2 million, and $0.5 million for the years ended December 31, 2022, 2021, and 2020, respectively. The Company received cash of $0.1 million, $0.5 million, and $1.1 million from stock option exercises during the years ended December 31, 2022, 2021, and 2020, respectively. The Company redeemed common stock with aggregate values of $0.2 million, $0.3 million, and $1.0 million tendered in payment for stock option exercises during the years ended December 31, 2022, 2021, and 2020, respectively. Restricted Stock Awards. Common stock issued under the Company’s restricted stock plan may not be sold or otherwise transferred until restrictions have lapsed or performance objectives have been obtained. During the vesting periods, participants have voting rights and receive dividends on all time restricted shares and vesting performance restricted shares. Upon termination of employment, common shares upon which restrictions have not lapsed must be returned to the Company. All restricted share awards are classified as equity awards. The fair value of equity-classified restricted stock awards is amortized as compensation expense on a straight-line basis over the period restrictions lapse or performance goals are met. Compensation expense related to restricted stock awards of $9.6 million, $8.9 million and $7.5 million was included in employee benefits on the Company’s consolidated statements of income for the years ended December 31, 2022, 2021, and 2020, respectively. Related income tax expense of $0.3 million for the year ended December 31, 2022, related income tax benefit of $0.3 million was recognized for the year ended December 31, 2021, and related income tax expense of $0.1 million was recognized for the year ended December 31, 2020. The following table presents information regarding the Company’s restricted stock: As of December 31, 2022 Number of Weighted-Average Restricted stock, beginning of year 521,012 $ 39.73 Granted 458,176 38.67 Vested (131,199) 39.92 Forfeited (106,891) 38.61 Restricted stock, end of year 741,098 $ 38.94 During 2022, the Company issued 458,176 restricted common shares. The 2022 restricted share awards included 263,582 performance restricted shares, of which 131,791 vest in varying percentages upon achievement of defined return on equity performance goals, and 131,791 vest in varying percentages upon achievement of defined total return to shareholder goals. The defined return to shareholder goals related to the 2019 performance restricted stock grants were not met resulting in the cancellation of 27,247 performance shares. Vesting of the 2022 performance restricted shares is also contingent on employment as of March 15, 2025. Additionally, 221,841 time-restricted shares were issued during 2022, of which 38,845 vest one year from the grant date, and the remaining 182,996 vest one-third on each annual anniversary of the grant date, contingent on continued employment through the vesting dates. As of December 31, 2022, there was $15.8 million of unrecognized compensation cost related to non-vested, restricted stock awards expected to be recognized over a period of 1.24 years.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
Employee Benefit Plans	Dec. 31, 2022
Compensation Related Costs [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLAN Savings Plan. In addition, the Company has a contributory employee savings plan. All employees are eligible to participate in the plan. Employee participation in the plan is at the option of the employee. The Company contributed 100% of the first 6% of the participating employee’s eligible compensation in 2022, 2021, and 2020, respectively. Contribution expense for this plan of $13.5 million, $8.8 million, and $8.9 million in 2022, 2021, and 2020, respectively, is included in employee benefits expense in the Company’s consolidated statements of income.

Other Comprehensive Income

Other Comprehensive Income	12 Months Ended
Other Comprehensive Income	Dec. 31, 2022
Equity [Abstract]
Other Comprehensive Income	OTHER COMPREHENSIVE INCOME (LOSS) The gross amounts of each component of other comprehensive (loss) income and the related tax effects for the periods indicated are as follows: Year Ended December 31, 2022 Before Tax Amount Tax Expense (Benefit) Net of Tax Amount Investment securities available-for sale: Change in net unrealized loss during period $ (613.1) $ (152.4) $ (460.7) Reclassification adjustment for net gains included in net income 24.4 5.5 18.9 Reclassification adjustment for securities transferred from held-to-maturity to available-for-sale 0.2 0.1 0.1 Net change in unamortized gains on available-for-sale securities transferred into held-to-maturity (26.1) (6.6) (19.5) Change in net unrealized loss on derivatives (6.7) (1.8) (4.9) Total other comprehensive loss $ (621.3) $ (155.2) $ (466.1) Year Ended December 31, 2021 Before Tax Amount Tax Expense (Benefit) Net of Tax Amount Investment securities available-for sale: Change in net unrealized loss during period $ (113.7) $ (28.7) $ (85.0) Reclassification adjustment for net gains included in net income (1.1) (0.3) (0.8) Net change in unamortized gains on available-for-sale securities transferred into held-to-maturity 20.2 5.1 15.1 Change in net unrealized loss on derivatives 4.2 1.1 3.1 Total other comprehensive loss $ (90.4) $ (22.8) $ (67.6) Year Ended December 31, 2020 Before Tax Amount Tax Expense (Benefit) Net of Tax Amount Investment securities available-for sale: Change in net unrealized gains during period $ 61.8 $ 15.8 $ 46.0 Reclassification adjustment for net gains included in net income (0.3) (0.1) (0.2) Change in net unrealized loss on derivatives 0.2 — 0.2 Defined benefits post-retirement benefit plan: Change in net actuarial gains (0.5) (0.1) (0.4) Total other comprehensive income $ 61.2 $ 15.6 $ 45.6 The components of accumulated other comprehensive loss, net of income taxes, are as follows: Years ended December 31, 2022 2021 Net unrealized loss on investment securities available-for-sale $ (471.0) $ (29.0) Net unrealized (loss) gain on investment securities transferred to held-to-maturity (4.5) 15.0 Net unrealized (loss) gain on derivatives (1.6) 3.0 Net accumulated other comprehensive loss $ (477.1) $ (11.0)

Condensed Financial Information

Condensed Financial Information (Parent Company Only)	12 Months Ended
Condensed Financial Information (Parent Company Only)	Dec. 31, 2022
Condensed Financial Information Disclosure [Abstract]
Condensed Financial Information (Parent Company Only)	CONDENSED FINANCIAL INFORMATION (PARENT COMPANY ONLY) Following is condensed financial information of First Interstate BancSystem, Inc. December 31, 2022 2021 Condensed balance sheets: Cash and cash equivalents $ 154.8 $ 181.1 Investment in bank subsidiary 2,985.8 1,948.9 Advances to subsidiaries, net 0.1 5.9 Other assets 240.7 63.2 Total assets $ 3,381.4 $ 2,199.1 Other liabilities $ 45.6 $ 26.8 Long-term debt 98.9 98.7 Subordinated debentures held by subsidiary trusts 163.1 87.0 Total liabilities 307.6 212.5 Stockholders’ equity 3,073.8 1,986.6 Total liabilities and stockholders’ equity $ 3,381.4 $ 2,199.1 Years Ended December 31, 2022 2021 2020 Condensed statements of income: Dividends from subsidiaries $ 360.0 $ 160.0 $ 130.0 Other interest income 0.4 — 0.1 Other income, primarily management fees from subsidiaries 51.7 41.3 28.7 Total income 412.1 201.3 158.8 Salaries and benefits 40.6 36.4 31.5 Interest expense 12.6 8.2 6.6 Acquisition related expenses 62.3 11.6 — Other operating expenses, net 25.0 17.6 15.6 Total expenses 140.5 73.8 53.7 Earnings before income tax benefit 271.6 127.5 105.1 Income tax benefit (18.9) (7.6) (6.1) Income before undistributed earnings of subsidiaries 290.5 135.1 111.2 Undistributed (loss) earnings of subsidiaries (88.3) 57.0 50.0 Net income $ 202.2 $ 192.1 $ 161.2 Years Ended December 31, 2022 2021 2020 Condensed statements of cash flows: Cash flows from operating activities: Net income $ 202.2 $ 192.1 $ 161.2 Adjustments to reconcile net income to cash provided by operating activities: Undistributed losses (earnings) of subsidiaries 88.3 (57.0) (50.0) Stock-based compensation expense 9.6 8.9 7.5 Other, net (151.2) (3.2) (13.6) Net cash provided by operating activities 148.9 140.8 105.1 Cash flows from investing activities: Acquisition of bank holding company, net of cash and cash equivalents received (0.8) — — Net cash used in investing activities $ (0.8) $ — $ — Years Ended December 31, 2022 2021 2020 Cash flows from financing activities: Net increase in advances from subsidiaries $ 206.5 $ 23.7 $ 16.7 Proceeds from issuance of long-term debt — — 98.6 Proceeds from issuance of common stock, net of stock issuance costs 0.1 0.4 1.1 Purchase and retirement of common stock (198.9) (5.4) (116.8) Dividends paid to common stockholders (182.1) (101.6) (128.6) Net cash used in financing activities (174.4) (82.9) (129.0) Net change in cash and cash equivalents (26.3) 57.9 (23.9) Cash and cash equivalents, beginning of year 181.1 123.2 147.1 Cash and cash equivalents, end of year $ 154.8 $ 181.1 $ 123.2

Fair Value Measurements

Fair Value Measurements	12 Months Ended
Fair Value Measurements	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. There is a fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The three levels of inputs that may be used to measure fair value are as follows: • Level 1 - Quoted prices in active markets for identical assets or liabilities • Level 2 - Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities • Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of assets or liabilities The methodologies used by the Company in determining the fair values of each class of financial instruments are based primarily on the use of independent, market-based data to reflect a value that would be reasonably expected in an orderly transaction between market participants at the measurement date, and therefore are classified within Level 2 of the valuation hierarchy. There have been no significant changes in the valuation techniques during the periods ended December 31, 2022 and 2021. The Company’s policy is to recognize transfers between levels as of the end of the reporting period. Transfers in and out of Level 1, Level 2, and Level 3 are recognized on the actual transfer date. There were no transfers between fair value hierarchy levels during the years ended December 31, 2022 and 2021. Further details on the methods used to estimate the fair value of each class of financial instruments above are discussed below: Investment Debt Securities Available-for-Sale . The Company obtains fair value measurements for investment securities from an independent pricing service. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information, and the investment’s terms and conditions, among other things. Vendors chosen by the Company are widely recognized vendors whose evaluations support the pricing functions of financial institutions, investment and mutual funds, and portfolio managers. If needed, a broker may be utilized to determine the reported fair value of investment securities. Loans Held for Sale. Fair value measurements for residential real estate loans held for sale are obtained from an independent pricing service. The fair value measurements consider observable data that may include binding contracts or quotes or bids from third party investors as well as loan level pricing adjustments. Loans that are reclassified into loans held for sale from loans held for investment are recorded at the lower of cost or fair value less costs to sell, except for certain loans which are recorded at fair value, determined individually, based on discounted payoffs and quotes or bids from third party investors, or based on the terms of the loans, such as interest rate, maturity date, reset term, as well as sales, quotes, or bids of similar assets. Interest Rate Swap Contracts. Fair values for derivative interest rate swap contracts and interest rate collars are based upon the estimated amounts to settle the contracts considering current interest rates and are calculated using discounted cash flows that are observable or that can be corroborated by observable market data. The inputs used to determine fair value include the three-month LIBOR forward curve to estimate variable rate cash inflows and the federal funds effective swap rate to estimate the discount rate. The estimated variable rate cash inflows are compared to the fixed rate outflows and such difference is discounted to a present value to estimate the fair value of the interest rate swaps. The change in the value of derivative assets attributable to basis risk, or the risk that offsetting investments in a hedging strategy will not experience price changes in entirely opposite directions from each other, was not significant in the reported periods. The Company also obtains and compares the reasonableness of the pricing from an independent third party. For purposes of potential valuation adjustments to our derivative positions, we evaluate the credit risk of our counterparties as well as ours. Accordingly, we have considered factors such as the likelihood of our default and the default of our counterparties, our net exposures and remaining contractual life, among other things, in determining if any fair value adjustments related to credit risk are required. The change in value of derivative assets and derivative liabilities attributable to credit risk was not significant during the reported periods. Interest Rate Lock Commitments. Fair value measurements for interest rate lock commitments are obtained from an independent pricing service. The fair value measurements consider observable data that may include prices available from secondary market investors taking into consideration various characteristics of the loan, including the loan amount, interest rate, value of the servicing, and loan to value ratio, among other things. Observable data is then adjusted to reflect changes in interest rates, the Company’s estimated pull-through rate, and estimated direct costs necessary to complete the commitment into a closed loan net of origination and processing fees collected from the borrower. Forward Loan Sales Contracts. The fair value measurements for forward loan sales contracts are obtained from an independent pricing service. The fair value measurements consider observable data that includes sales of similar loans. Deferred Compensation Plan Assets and Liabilities. The fair values of deferred compensation plan assets and liabilities are based primarily on the use of independent, market-based data to reflect a value that would be reasonably expected in an orderly transaction between market participants at the measurement date. These investments are in the same funds and purchased in the same amounts as the participants’ selected investments, which represent the underlying liabilities to plan participants. Deferred compensation plan liabilities are recorded at amounts due to participants, based on the fair value of participants’ selected investments. Financial assets and financial liabilities measured at fair value on a recurring basis are as follows: Fair Value Measurements at Reporting Date Using As of December 31, 2022 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investment debt securities available-for-sale: U.S. Treasury notes $ 642.7 $ — $ 642.7 $ — State, county, and municipal securities 263.7 — 263.7 — Obligations of U.S. government agencies 198.9 — 198.9 — U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 4,259.7 — 4,259.7 — Private mortgage-backed securities 228.0 — 228.0 — Collateralized loan obligations 1,111.6 — 1,111.6 — Corporate Securities 241.5 — 241.5 — Loans held for sale 79.9 — 79.9 — Derivative assets: Interest rate swap contracts 45.1 — 45.1 — Forward loan sales contracts 0.1 — 0.1 — Derivative liabilities: Interest rate collars 5.4 — 5.4 — Interest rate swap contracts 154.2 — 154.2 — Deferred compensation plan assets 18.7 — 18.7 — Deferred compensation plan liabilities 18.7 — 18.7 — Fair Value Measurements at Reporting Date Using As of December 31, 2021 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investment debt securities available-for-sale: U.S. Treasury notes $ 684.7 $ 684.7 $ — $ — State, county, and municipal securities 427.5 — 427.5 — Obligations of U.S. government agencies 346.9 — 346.9 — U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 2,018.1 — 2,018.1 — Private mortgage-backed securities 173.4 — 173.4 — Collateralized loan obligations 899.4 — 899.4 — Corporate securities 270.5 — 270.5 — Loans held for sale 30.1 — 30.1 — Derivative assets: Interest rate swap contracts 26.3 — 26.3 — Interest rate lock commitments 1.8 — 1.8 — Derivative liabilities: Interest rate swap contracts 18.2 — 18.2 — Deferred compensation plan assets 21.4 — 21.4 — Deferred compensation plan liabilities 21.4 — 21.4 — Additionally, from time to time, certain assets are measured at fair value on a non-recurring basis. Adjustments to fair value generally result from the application of lower-of-cost-or-market accounting or write-downs of individual assets due to credit deterioration. The following table presents information about the Company’s assets and liabilities measured at fair value on a non-recurring basis: Fair Value Measurements at Reporting Date Using As of December 31, 2022 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Gains (Losses) Collateral-dependent loans $ 39.1 $ — $ — $ 39.1 $ — Other real estate owned 12.7 — — 12.7 — Long-lived assets to be disposed of by sale 5.5 — — 5.5 (0.2) Fair Value Measurements at Reporting Date Using As of December 31, 2021 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Gains (Losses) Collateral-dependent loans $ 11.7 $ — $ — $ 11.7 $ — Other real estate owned 2.0 — — 2.0 — Long-lived assets to be disposed of by sale 1.3 — — 1.3 — Collateral-dependent Loans. Collateral-dependent loans are reported at the fair value of the underlying collateral if repayment is expected solely from collateral. The collateral-dependent loans are reported at fair value through specific valuation allowance allocations. In addition, when it is determined that the fair value of a collateral-dependent loan is less than the recorded investment in the loan, the carrying value of the loan is adjusted to fair value through a charge to the allowance for credit losses. Collateral values are estimated using independent appraisals and management estimates of current market conditions. As of December 31, 2022, the Company had collateral-dependent loans with a carrying and fair value of $39.1 million. As of December 31, 2021, the Company had collateral-dependent loans with a carrying and fair value of $11.7 million. OREO. The fair values of OREO are estimated using independent appraisals and management estimates of current market conditions. Upon initial recognition, write-downs based on the foreclosed asset’s fair value at foreclosure are reported through charges to the allowance for credit losses. Periodically, the fair value of foreclosed assets is remeasured with any subsequent write-downs charged to OREO expense in the period in which they are identified. Long-lived Assets to be Disposed of by Sale. Long-lived assets to be disposed of by sale are carried at the lower of carrying value or fair value less estimated costs to sell. The fair values of long-lived assets to be disposed of by sale are based upon observable market data and management estimates of current market conditions. As of December 31, 2022, the Company had long-lived assets to be disposed of by sale with carrying values of $5.7 million, reduced by write-downs of $0.2 million charged to other expense, and fair values aggregating $5.5 million. As of December 31, 2021, the Company had long-lived assets to be disposed of by sale with carrying and fair values aggregating $1.3 million, with no write-downs charged to other expense. The following table presents additional quantitative information about assets measured at fair value on a non-recurring basis and for which the Company has utilized Level 3 inputs to determine fair values: As of December 31, 2022 Fair Value Valuation Technique Unobservable Inputs Range (Weighted Average) Collateral-dependent loans $ 39.1 Appraisal Appraisal adjustment 0% - 45% (7%) Other real estate owned 12.7 Appraisal Appraisal adjustment 15 - 36 (22) Long-lived assets to be disposed of by sale 5.5 Appraisal Appraisal adjustment 0 - 6 (3) As of December 31, 2021 Collateral-dependent loans $ 11.7 Appraisal Appraisal adjustment 1% - 18% (7%) The Company is required to disclose the fair value of financial instruments for which it is practical to estimate fair value. The methodologies for estimating the fair value of financial instruments that are measured at fair value on a recurring or non-recurring basis are discussed above. The methodologies for estimating the fair value of other financial instruments are discussed below. For financial instruments bearing a variable interest rate where no credit risk exists, it is presumed that recorded book values are reasonable estimates of fair value. Financial Assets. Carrying values of cash, cash equivalents, and accrued interest receivable approximate fair values due to the liquid and/or short-term nature of these instruments. Fair values for investment securities held-to-maturity are obtained from an independent pricing service, which considers observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information, and the investment’s terms and conditions, among other things. Fair values of fixed rate loans and variable rate loans that reprice on an infrequent basis are estimated using an exit price by discounting future cash flows using current interest rates at which similar loans with similar terms would be made to borrowers of similar credit quality using an exit price notion. Carrying values of variable rate loans that reprice frequently, and with no change in credit risk, approximate the fair values of these instruments. Financial Liabilities. The fair values of demand deposits, savings accounts, securities sold under repurchase agreements, and accrued interest payable are the amounts payable on demand at the reporting date. The fair values of fixed-maturity certificates of deposit are estimated using external market rates currently offered for deposits with similar remaining maturities. The fair values of derivative liabilities are obtained from an independent pricing service, which considers observable data that may include the three-month LIBOR forward curve, the federal funds effective swap rate and cash flows, among other things. The carrying values of the interest-bearing demand notes to the United States Treasury are deemed an approximation of fair values due to the frequent repayment and repricing at market rates. The fixed and floating rate subordinated debentures, floating rate subordinated term loan, notes payable to the FHLB, fixed rate subordinated term debt, and capital lease obligation are estimated by discounting future cash flows using current rates for advances with similar characteristics. Commitments to Extend Credit and Standby Letters of Credit. The fair value of commitments to extend credit and standby letters of credit, based on fees currently charged to enter into similar agreements, is not significant. The estimated fair values of financial instruments that are reported in the Company’s consolidated balance sheets, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value, are as follows: ` Fair Value Measurements at Reporting Date Using As of December 31, 2022 Carrying Amount Estimated Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Financial assets: Cash and cash equivalents $ 870.5 $ 870.5 $ 870.5 $ — $ — Investment debt securities available-for-sale 6,946.1 6,946.1 — 6,946.1 — Investment debt securities held-to-maturity 3,451.8 3,052.2 — 3,052.2 — Accrued interest receivable 118.3 118.3 — 118.3 — Mortgage servicing rights, net 31.1 37.4 — 37.4 — Loans held for sale 79.9 79.9 — 79.9 — Net loans held for investment 17,879.1 17,552.1 — 17,513.0 39.1 Derivative assets 45.2 45.2 — 45.2 — Deferred compensation plan assets 18.7 18.7 — 18.7 — Total financial assets $ 29,440.7 $ 28,720.4 $ 870.5 $ 27,810.8 $ 39.1 Financial liabilities: Total deposits, excluding time deposits $ 23,145.2 $ 23,145.2 $ 23,145.2 $ — $ — Time deposits 1,928.4 1,876.1 — 1,876.1 — Securities sold under repurchase agreements 1,052.9 1,052.9 — 1,052.9 — Other borrowed funds 2,327.0 2,327.0 — 2,327.0 — Accrued interest payable 14.5 14.5 — 14.5 — Long-term debt 120.8 116.3 — 116.3 — Subordinated debentures held by subsidiary trusts 163.1 155.8 — 155.8 — Derivative liabilities 159.6 159.6 — 159.6 — Deferred compensation plan liabilities 18.7 18.7 — 18.7 — Total financial liabilities $ 28,930.2 $ 28,866.1 $ 23,145.2 $ 5,720.9 $ — Fair Value Measurements at Reporting Date Using As of December 31, 2021 Carrying Amount Estimated Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial assets: Cash and cash equivalents $ 2,344.8 $ 2,344.8 $ 2,344.8 $ — $ — Investment debt securities available-for-sale 4,820.5 4,820.5 684.7 4,135.8 — Investment debt securities held-to-maturity 1,687.6 1,667.5 — 1,667.5 — Accrued interest receivable 47.4 47.4 — 47.4 — Mortgage servicing rights, net 28.2 28.2 — 28.2 — Loans held for sale 30.1 30.1 — 30.1 — Net loans held for investment 9,209.4 9,254.3 — 9,242.6 11.7 Derivative assets 28.1 28.1 — 28.1 — Deferred compensation plan assets 21.4 21.4 — 21.4 — Total financial assets $ 18,217.5 $ 18,242.3 $ 3,029.5 $ 15,201.1 $ 11.7 Financial liabilities: Total deposits, excluding time deposits $ 15,303.1 $ 15,303.1 $ 15,303.1 $ — $ — Time deposits 966.5 963.1 — 963.1 — Securities sold under repurchase agreements 1,051.1 1,051.1 — 1,051.1 — Accrued interest payable 3.7 3.7 — 3.7 — Long-term debt 112.4 120.7 — 120.7 — Subordinated debentures held by subsidiary trusts 87.0 85.5 — 85.5 — Derivative liabilities 18.2 18.2 — 18.2 — Deferred compensation plan liabilities 21.4 21.4 — 21.4 — Total financial liabilities $ 17,563.4 $ 17,566.8 $ 15,303.1 $ 2,263.7 $ —

Related Party Transactions

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2022
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS Certain executive officers, directors, and greater than 5% shareholders of the Company and certain entities and individuals related to such persons had transactions with the Company in the ordinary course of business. These parties were deposit clients of the Bank and incurred indebtedness in the form of loans, as clients, of $18.9 million and $19.5 million at December 31, 2022 and 2021, respectively. During 2022, new loans and advances on existing loans of $6.5 million were funded and loan repayments totaled $7.1 million. No loans were removed or added due to changes in related parties during the year. All deposit and loan transactions were made on substantially the same terms, including interest rates and collateral, as those prevailing at the time for comparable transactions with persons not related to the Company and do not involve more than a normal risk of collectability or present other unfavorable features. The Company leased a portion of our aircraft hangar to the Scott family services group’s related entity during 2022, 2021, and 2020 and also provided pilot services to the Scott family services group’s related entity during 2021 and 2020. During 2022, 2021, and 2020, the Company received payments from the related entity of $26 thousand, $61 thousand, and $54 thousand, respectively, for hangar use, pilot fees, and reimbursement of certain third-party operating expenses related to the use of the aircraft. The Company purchased services from an entity which includes certain members of the Scott family services group. Services provided for the Company’s benefit include shareholder communication and corporate governance coordination. During 2022, 2021, and 2020, the Company paid $102 thousand, $87 thousand, and $85 thousand, respectively, for these services. In addition, the Company provides human resource services to members of the Company’s control group during 2021 and 2020. The Company received payments from these related parties of $0.7 million during 2021 and 2020 for the reimbursement of human resource services provided. Additionally, the Company, as it agreed in connection with its acquisition of Great Western, reimbursed an aggregate of $8.2 million of the Scott family control group’s acquisition expenses related to the GWB acquisition.

Authoritative Accounting Guidan

Authoritative Accounting Guidance	12 Months Ended
Authoritative Accounting Guidance	Dec. 31, 2022
Accounting Standards Update and Change in Accounting Principle [Abstract]
Recent Authoritative Accounting Guidance	RECENT AUTHORITATIVE ACCOUNTING GUIDANCE ASU 2020-04, “Reference Rate Reform (Topic 848), Facilitation of the Effects of Reference Rate Reform on Financial Accounting.” In March 2020, the FASB issued ASU 2020-04, which provides temporary exceptions that are optional for applying GAAP to loan and lease agreements, derivative contracts, and other transactions affected by the anticipated transition away from LIBOR toward new interest rate benchmarks. For transactions that are modified because of reference rate reform and that meet certain scope guidance (i) modifications of loan agreements should be accounted for by prospectively adjusting the effective interest rate, with such modification considered to be "minor" so that any existing unamortized origination fees/costs will carry forward and continue to be amortized and (ii) modifications of lease agreements should be accounted for as a continuation of the existing agreement with no reassessments of the lease classification and the discount rate or remeasurements of lease payments that otherwise would be required for modifications will not be accounted for as separate contracts. ASU 2020-04 is effective March 12, 2020 through December 31, 2022. An entity may elect to apply ASU 2020-04 for contract modifications as of January 1, 2020, or prospectively from a date within an interim period that includes or is subsequent to March 12, 2020, up to the date that the financial statements are available to be issued. Once elected for a Topic or an Industry Subtopic within the Codification, the amendments in this ASU must be applied prospectively for all eligible contract modifications for that Topic or Industry Subtopic. The Company adopted certain elections related to cash flow hedges which did not have a significant impact on the Company’s financial position or results of operations. Based upon the amendments provided in ASU 2022-06 discussed below, ASU 2020-04 can generally be applied through December 31, 2024. ASU 2021-01, “ Reference Rate Reform (Topic 848) ” In January 2021, the FASB issued ASU 2021-01, Reference Rate Reform Topic 848 , that clarifies certain exceptions that are optional in Topic 848 for contract modifications and hedge accounting and apply those exceptions to derivatives that are affected by the discounting transition. An entity may elect to apply the amendments in this ASU on a full retrospective basis as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or on a prospective basis to new modifications from any date within an interim period that includes or is subsequent to the date of the issuance of a final ASU. If an entity elects to apply any of the amendments in this ASU for an eligible hedging relationship, any adjustments as a result of those elections must be reflected as of the date the entity applies the election. The amendments in this ASU do not apply to contract modifications made, new hedging relationships entered into, or existing hedging relationships evaluated for effectiveness in periods after December 31, 2022, except for hedging relationships existing as of December 31, 2022, that apply certain exceptions that are optional in which the accounting effects of the hedging activity are recorded through the end of the hedging relationship (including periods after December 31, 2022). The Company is currently evaluating the impact of the standard and does not anticipate it will have a significant impact on the Company’s financial position or results of operations. ASU 2021-08, “ Business Combinations (Topic 805), Accounting for Contract Assets and Contract Liabilities from Contracts with Customers ” In October 2021, the FASB issued ASU 2021-08, Business Combinations Topic 805, Accounting for Contract Assets and Contract Liabilities from Contracts with Customers , to address diversity in practice and inconsistency related to the accounting for revenue contracts with customers acquired in a business combination. The amendments require that an entity recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with Topic 606 as if it had originated the contracts. The amendments also provide certain practical expedients for acquirers when recognizing and measuring acquired contract assets and contract liabilities from revenue contracts in a business combination and applies to contract assets and contract liabilities from other contracts to which the provisions of Topic 606 apply. The amendments are effective for fiscal years beginning after December 15, 2022, and interim periods within those fiscal years. Entities should apply the amendments prospectively to business combinations that occur after the effective date. The Company is currently evaluating the impact of the standard and does not anticipate it will have a significant impact on the Company’s financial position or results of operations. ASU 2022-01, “ Derivatives and Hedging (Topic 815), Fair Value Hedging—Portfolio Layer Method ” In March 2022, the FASB issued ASU 2022-01, Derivatives and Hedging Topic 815, Fair Value Hedging—Portfolio Layer Method that clarifies the accounting for and promotes consistency in the reporting of hedge basis adjustments applicable to both a single hedged layer and multiple hedged layers. The amendments allow nonprepayable financial assets also to be included in a closed portfolio hedged using the portfolio layer method. That expanded scope permits an entity to apply the same portfolio hedging method to both prepayable and nonprepayable financial assets, thereby allowing consistent accounting for similar hedges. The amendments are effective for fiscal years beginning after December 15, 2022, and interim periods within those fiscal years. Entities should apply the amendments prospectively to business combinations that occur after the effective date. Early adoption in an interim period is permitted for public business entities, with the effect of adopting the amendments related to basis adjustments reflected as of the beginning of the fiscal year of adoption. The Company is currently evaluating the impact of the standard and does not anticipate it will have a significant impact on the Company’s financial position or results of operations. ASU 2022-02, “ Financial Instruments—Credit Losses (Topic 326), Troubled Debt Restructurings and Vintage Disclosures ” In March 2022, the FASB issued ASU 2022-02, Financial Instruments—Credit Losses (Topic 326), Troubled Debt Restructurings (TDRs) and Vintage Disclosures that eliminate the accounting guidance for TDRs by creditors in Subtopic 310-40, Receivables—Troubled Debt Restructurings by Creditors, while enhancing disclosure requirements for certain loan refinancings and restructurings by creditors when a borrower is experiencing financial difficulty. Rather than applying the recognition and measurement guidance for TDRs, an entity must apply the loan refinancing and restructuring guidance to determine whether a modification results in a new loan or a continuation of an existing loan. The amendment also requires an entity disclose current-period gross writeoffs by year of origination for financing receivables and net investments in leases within the scope of Subtopic 326. The amendments are effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. Entities should apply the amendments prospectively except for the transition method related to the recognition and measurement of TDRs, an entity has the option to apply a modified retrospective transition method, resulting in a cumulative-effect adjustment to retained earnings in the period of adoption. Early adoption of the amendments are permitted, including adoption in an interim period. If an entity elects to early adopt the amendments in an interim period, the guidance should be applied as of the beginning of the fiscal year that includes the interim period. An entity may elect to early adopt the amendments about TDRs and related disclosure enhancements separately from the amendments related to vintage disclosures. The Company is currently evaluating the impact of the standard and does not anticipate it will have a significant impact on the Company’s financial position or results of operations.

Subsequent Events

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS Subsequent events have been evaluated for potential recognition and disclosure through the date financial statements were filed with the Securities and Exchange Commission. On January 25, 2023, the Company declared a quarterly dividend to common shareholders of $0.47 per share, which was paid on February 17, 2023 to shareholders of record as of February 7, 2023. No other events requiring recognition or disclosure were identified.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2022
Accounting Policies [Abstract]
Revenue	Revenue Recognition. The Company recognizes revenue as it is earned based on contractual terms, as transactions occur, or as services are provided and collectability is reasonably assured. The principal source of revenue is interest income from loans and investments. The Company also earns non-interest income from various banking and financial services offered to its clients. Certain specific policies related to non-interest income include the following: Wealth management and trust fee income Wealth management and trust fee income represents monthly or other periodic fees due from wealth management clients as consideration for managing the clients’ assets. Wealth management and trust services include custody of assets, investment management, fees for trust services and similar fiduciary activities. Revenue is recognized when our performance obligation is completed. The Company does not earn performance-based incentives. Optional services such as estate settlement and other court appointed services are available to existing trust and asset management clients. The Company’s performance obligation for these transactional-based services is generally satisfied, and related revenue recognized, at a point in time. Service charges on deposit accounts Service charges on deposit accounts represent general service fees for account maintenance and activity- or transaction-based fees and consist of transaction-based revenue, time-based revenue (service period), item-based revenue or some other individual attribute-based revenue. Revenue is recognized when our performance obligation is completed for account maintenance services or when a transaction has been completed (such as a wire transfer or check orders). Payment for such performance obligations are generally received at a point in time when the performance obligations are satisfied. Interchange and other fees Interchange and other fees primarily represent debit and credit card income comprised of interchange fees earned whenever the Company’s debit and credit cards are processed through card payment networks such as MasterCard. ATM fees are primarily generated when a Company cardholder uses a non-Company ATM or a non-Company cardholder uses a Company ATM. Merchant services income primarily represents fees charged to merchants to process their debit and credit card transactions, in addition to account management fees. Swap fee income primarily represents income associated with the execution of dealer bank swap agreements. Other service charges include revenue from processing wire transfers, bill pay service, cashier’s checks, and other services. The Company’s performance obligation for interchange and other service charges are largely satisfied, and related revenue recognized, when completion of the services are rendered at a point in time. Annuity and insurance commissions Annuity and insurance commissions primarily represent commissions received on annuity and insurance product sales. The Company acts as an intermediary between the Company’s client and the insurance carrier. The Company’s performance obligation is generally satisfied upon the issuance of the annuity or insurance policy, the carrier then remits the commission payment to the Company, and the Company recognizes the revenue at a point in time.
Consolidation Policy	Basis of Presentation . The Company’s consolidated financial statements include the accounts of the Parent Company and its operating subsidiaries. As of December 31, 2022, the Company had one significant subsidiary, First Interstate Bank (“FIB”). All significant intercompany balances and transactions have been eliminated in consolidation. Certain reclassifications, none of which were material, have been made in the consolidated financial statements for 2021 and 2020 to conform to the 2022 presentation. These reclassifications did not change previously reported net income or stockholders’ equity.
Equity Method Investments	Equity Method Investments. The Company has investments in real estate joint ventures that are not consolidated because the Company does not own a majority voting interest, control the operations, or receive a majority of the losses or earnings of the joint venture. These joint ventures are accounted for using the equity method of accounting whereby the Company initially records its investment at cost (or fair value at the date of acquisition) and then subsequently adjusts the carrying value for the Company’s proportionate share of distributions and earnings or losses of the joint ventures.
Variable Interest Entities	Variable Interest Entities. The Company’s wholly-owned business trusts, FI Statutory Trust I (“Trust I”), FI Capital Trust II (“Trust II”), FI Statutory Trust III (“Trust III”), FI Capital Trust IV (“Trust IV”), FI Statutory Trust V (“Trust V”), FI Statutory Trust VI (“Trust VI”), Northwest Bancorporation Capital Trust I (“Trust VII”), GWB Capital Trust VI (“Trust VIII”), Sunstate Bancshares Trust II (Trust IX”), Great Western Statutory Trust IV (“Trust X”), HF Financial Capital Trust III (“Trust XI”), HF Trust IV (“Trust XII”), HF Trust V (“Trust XIII”), and HF Trust VI (“Trust XIV”) are variable interest entities for which the Company is not a primary beneficiary. Accordingly, the accounts of Trust I through Trust XIV are not included in the accompanying consolidated financial statements, and are instead accounted for using the equity method of accounting.
Assets Held In Fiduciary Or Agency Capacity	Assets Held in Fiduciary or Agency Capacity. The Company holds certain trust assets in a fiduciary or agency capacity. The Company also purchases and sells federal funds as an agent. These and other assets held in an agency or fiduciary capacity are not assets of the Company and, accordingly, are not included in the accompanying consolidated financial statements.
Use of Estimates	Use of Estimates. The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and income and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to change relate to the determination of the allowance for credit losses, the valuation of goodwill and intangible assets, and fair valuations of investment securities and other financial instruments.
Cash and Cash Equivalents	Cash and Cash Equivalents. For purposes of reporting cash flows, cash and cash equivalents include cash on hand, amounts due from banks, federal funds sold for less than three-month periods, and interest-bearing deposits in banks with original maturities of less than three months.
Goodwill and Core Deposit Intangibles	Goodwill . The excess purchase price over the fair value of net assets from acquisitions, or goodwill, is evaluated for impairment at least annually and on an interim basis if an event or circumstance indicates that it is likely impairment has occurred. Goodwill impairment is determined by comparing the fair value of a reporting unit to its carrying amount. In any given year the Company may elect to perform a qualitative assessment to determine whether it is more likely than not that the fair value of a reporting unit is in excess of its carrying value. If it is not more likely than not that the fair value of the reporting unit is in excess of the carrying value, or if the Company elects to bypass the qualitative assessment, a quantitative impairment test is performed. In performing a quantitative test for impairment, the fair value of net assets is estimated based on analyses of the Company’s market value, discounted cash flows and peer values. The determination of goodwill impairment is sensitive to market-based economics and other key assumptions used in determining or allocating fair value. Variability in the market and changes in assumptions or subjective measurements used to allocate fair value are reasonably possible and may have a material impact on our consolidated financial statements or results of operations. Core Deposit and Other Customer Relationship Intangibles. Intangible assets consist of core deposit intangibles and other customer relationship intangibles. Core deposit intangibles represent the intangible value of depositor relationships resulting from deposit liabilities assumed, as a result of acquisitions, and are amortized using an accelerated method based on the estimated weighted average useful lives of the related deposits, which is generally ten years. Other customer relationship intangibles represent the value of the identifiable intangible value assigned to customer relationships arising from acquired companies and are amortized using the straight-line method over the estimated useful life, which is 12 years.
Mortgage Servicing Rights	Mortgage Servicing Rights . The Company recognizes the rights to service mortgage loans for others, whether acquired or internally originated. Mortgage servicing rights are initially recorded at fair value based on comparable market data and are amortized in proportion to and over the period of estimated net servicing income. Mortgage servicing rights are evaluated quarterly for impairment by discounting the expected future cash flows, taking into consideration the estimated level of prepayments based on current industry expectations and the predominant risk characteristics of the underlying loans including loan type, note rate, and loan term. Impairment adjustments, if any, are recorded through a valuation allowance.
Premises and Equipment	Premises and Equipment . Buildings, furniture, and equipment are stated at cost less accumulated depreciation. Depreciation expense is computed using straight-line methods over estimated useful lives of 5 to 45 years for buildings and improvements and 3 to 15 years for furniture and equipment. Leasehold improvements and assets acquired under a financing lease are amortized over the shorter of their estimated useful lives or the terms of the related leases. Land is recorded at cost. Costs incurred for maintenance and repairs are expensed as incurred.
Company-Owned Life Insurance	Company-Owned Life Insurance . Key executive and group life insurance policies are recorded at their cash surrender value. Separate account group life insurance policies are subject to a stable value contract that offsets the impact of interest rate fluctuations on the market value of the policies and are recorded at the stabilized investment value. Increases in the cash surrender or stabilized investment value of insurance policies, as well as insurance proceeds received, are recorded as other non-interest income, and are not subject to income taxes.
Deferred Compensation Plan	Deferred Compensation Plan. The Company has a deferred compensation plan for the benefit of certain highly compensated officers and directors of the Company. The plan allows for discretionary employer contributions in excess of tax limits applicable to the Company’s 401(k) plan and the deferral of salary, short-term incentives, or director fees subject to certain limitations. Deferred compensation plan assets and liabilities are included in the Company’s consolidated balance sheets at fair value.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets. Long-lived assets, including premises and equipment and certain identifiable intangibles, are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. The amount of the impairment loss, if any, is based on the asset’s fair value
Other Real Estate Owned	Other Real Estate Owned (OREO). Real estate acquired in satisfaction of loans is initially carried at current fair value less estimated selling costs. Any excess of loan carrying value over the fair value of the real estate acquired is recorded as a charge to the allowance for credit losses. Subsequent declines in fair value less estimated selling costs are included in OREO expense. Subsequent increases in fair value less estimated selling costs are recorded as a reduction in OREO expense to the extent of recognized losses. Operating expenses, net of related income, and gains or losses on sales are included in OREO expense.
Restricted Equity Securities	Restricted Equity Securities. The Company, as a member of the FRB and the Federal Home Loan Bank of Des Moines (“FHLB”), is required to maintain investments in each of the organization’s capital stock.No ready market exists for the FHLB and FRB restricted equity securities, and they have no quoted market values. Restricted equity securities are periodically reviewed for impairment based on ultimate recovery of par value. The determination of whether a decline affects the ultimate recovery of par value is influenced by the significance of the decline compared to the cost basis of the restricted equity securities, length of time a decline has persisted, impact of legislative and regulatory changes on the issuing organizations, and the liquidity positions of the issuing organizations.
Derivatives and Hedging Activities	Derivatives and Hedging Activities. For asset and liability management purposes, the Company enters into interest rate swap contracts to hedge against changes in forecasted cash flows due to interest rate exposures. Interest rate swaps are contracts in which a series of interest payments are exchanged over a prescribed period. The notional amount upon which the interest payments are based is not exchanged. The Company formally assesses, both at the hedge's inception and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in cash flows of hedged items. The gain or loss on cash flow hedging instruments is initially reported as a component of other comprehensive income and subsequently reclassified into earnings in the same period during which the transaction affects earnings. When it is determined that a derivative is not highly effective as a hedge or that it has ceased to be a highly effective hedge, the Company discontinues hedge accounting prospectively when (a) it is determined that the derivative is no longer effective in offsetting changes in the cash flows of a hedged item (including forecasted transactions); (b) the derivative expires or is sold, terminated, or exercised; (c) the derivative is de-designated as a hedge instrument, because it is unlikely that a forecasted transaction will occur; or (d) management determines that designation of the derivative as a hedge instrument is no longer appropriate. When hedge accounting is discontinued because it is probable that a forecasted transaction will not occur, the derivative will continue to be carried on the balance sheet at its fair value, and gains and losses that were accumulated in other comprehensive income will be recognized immediately in earnings. In all other situations in which hedge accounting is discontinued, the derivative will be carried at its fair value on the balance sheet, with subsequent changes in its fair value recognized in current-period earnings. The Company also enters into certain interest rate swap contracts that are not designated as hedging instruments. These derivative contracts relate to transactions in which the Company enters into an interest rate swap with a client while at the same time entering into an offsetting interest rate swap with a third-party financial institution. Because the Company acts as an intermediary for the client, changes in the fair value of the underlying derivative contracts for the most part offset each other and do not significantly impact the Company’s results of operations. In the normal course of business, the Company enters into interest rate lock commitments to finance residential mortgage loans that are not designated as accounting hedges. These commitments, which contain fixed expiration dates, offer the borrower an interest rate guarantee provided the loan meets underwriting guidelines and closes within the timeframe established by the Company. Interest rate risk arises on these commitments and subsequently closed loans if interest rates change between the time of the interest rate lock and the delivery of the loan to the investor. Loan commitments related to residential mortgage loans intended to be sold are considered derivatives and are marked to market through earnings. In addition to the effects of the change in market interest rate, the fair value measurement of the derivative also contemplates the expected cash flows to be received from the counterparty from the future sale of the loan.
Earnings Per Common Share	Earnings Per Common Share . Basic and diluted earnings per common share are calculated using a two-class method. Under the two-class method, basic earnings per common share is calculated by dividing net income available to common shareholders by the weighted average number of common shares outstanding during the period, excluding outstanding participating securities. Participating securities include non-vested performance restricted stock awards granted and all non-vested time restricted stock awards. Diluted earnings per common share is calculated by dividing net income available to common shareholders by the weighted average number of common shares outstanding determined for the basic earnings per share calculation plus the dilutive effect of stock compensation using the treasury stock method.
Income Taxes	Income Taxes . The Parent Company and its subsidiaries have elected to be included in a consolidated federal income tax return. For state income tax purposes, the combined taxable income of the Parent Company and its subsidiaries is apportioned among the states in which operations take place. Federal and state income taxes attributable to the subsidiaries, computed on a separate return basis, are paid to or received from the Parent Company. The Company accounts for income taxes using the liability method. Under the liability method, deferred tax assets and liabilities are determined based on enacted income tax rates which will be in effect when the differences between the financial statement carrying values and tax bases of existing assets and liabilities are expected to be reported in taxable income.
Comprehensive Income	Comprehensive Income (Loss). Comprehensive income (loss) includes net income, as well as other changes in stockholders’ equity that result from transactions and economic events other than those with shareholders. In addition to net income, the Company’s comprehensive income (loss) includes the after tax effect of changes in unrealized gains and losses on available-for-sale investment securities and derivatives designated as fair value or cash flow hedges, and changes in the unamortized gain or loss on available-for-sale investment securities transferred to held-to-maturity.
Segment Reporting	Segment Reporting. An operating segment is defined as a component of a business for which separate financial information is available that is evaluated regularly by the chief operating decision maker in deciding how to allocate resources and evaluate performance. The “Segment Reporting” topic of the FASB ASC requires that public companies report certain information about operating segments. It also requires that public companies report certain information about their products and services, the geographic areas in which they operate, and their major clients. The Company is a holding company for a regional community bank, which offers a wide array of products and services to its clients. The Company has one reporting unit and one operating segment, community banking, which encompasses commercial and consumer banking services offered to individuals, businesses, municipalities and other entities.
Advertising Costs	Advertising Costs. Advertising costs are expensed as incurred.
Transfers of Financial Assets	Transfers of Financial Assets. Transfers of financial assets are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is deemed to be surrendered when the assets have been isolated from the Company; the transferee obtains the right, free of conditions that constrain it from taking advantage of that right, to pledge or exchange the transferred assets; and, the Company does not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity.
Stock-Based Compensation	Stock-Based Compensation. Compensation cost for all stock-based awards is measured at fair value on the date of grant and is recognized over the requisite service period for awards expected to vest. The impact of forfeitures of stock-based payment awards on compensation expense is recognized as forfeitures occur.
Fair Value Measurements	Fair Value Measurements. In general, fair value measurements are based upon quoted market prices, where available. If quoted market prices are not available, fair value measurements are estimated using relevant market information and other assumptions. Fair value estimates involve uncertainties and require some degree of judgment regarding interest rates, credit risk, prepayments and other factors. The use of different assumptions or estimation techniques may have a significant effect on the fair value amounts reported.
Business Combinations Policy	Business Combinations. The Company accounts for all business combinations using the acquisition method of accounting. Under this method of accounting, acquired assets and assumed liabilities are included with the acquirer's accounts as of the date of acquisition, with any excess of purchase price over the fair value of the net assets acquired recognized as either finite lived intangibles or capitalized as goodwill. In addition, acquisition related costs and restructuring costs are recognized as period expenses as incurred. Fair values are subject to refinement over the measurement period, not to exceed one year after the closing date.
Internal Use Software, Policy	Software. Capitalized software, stated at cost less accumulated amortization, includes purchased software, capitalizable application development costs associated with internally developed software, and cloud computing arrangements, including capitalizable implementation costs associated with hosting arrangements that are service contracts. Capitalized software is included in premises and equipment, net of accumulated depreciation on the Consolidated Balance Sheets. Amortization expense, generally computed on the straight-line method, is charged to furniture and equipment in the Consolidated Statements of Income over the estimated useful life of the software, generally three to five years, or the term of the hosting arrangement for implementation costs related to service contracts. Cloud computing arrangements include software as a service (SaaS), platform as a service (PaaS), infrastructure as a service (IaaS) and other similar hosting arrangements. The Company primarily utilizes SaaS and PaaS arrangements.
Investment Securities	Debt Security Investments. Investments in debt securities that the Company has the positive intent and ability to hold to maturity are classified as held-to-maturity and carried at amortized cost. Investments in debt securities that may be sold in response to or in anticipation of changes in interest rates and resulting prepayment risk, or other factors, are classified as available-for-sale and carried at fair value. The unrealized gains and losses on these securities are reported, net of applicable income taxes, as a separate component of stockholders’ equity and comprehensive income. Management determines the appropriate classification of securities at the time of purchase and at each reporting date management reassesses the appropriateness of the classification.
Credit Loss, Financial Instrument	Allowance for Credit Losses - Held-to-Maturity Securities: Management measures expected credit losses on held-to-maturity debt securities on a collective basis by major security type. Accrued interest receivable on held-to-maturity debt securities is excluded from the estimate of credit losses. The estimate of expected credit losses considers historical credit loss information that is adjusted for current conditions and reasonable and supportable forecasts. Management classifies the held-to-maturity portfolio into the following major security types: U.S. Treasury notes. U.S. Treasury notes issued by the U.S. Department of the Treasury are guaranteed by the U.S. government with very little risk to default. State, county, and municipal securities. Municipal bonds issued by municipal governments within the U.S. These types of securities are primarily composed of general obligation bonds, or municipal bonds backed by the credit and taxing power of the issuing jurisdiction and revenue obligation bonds, or municipal bonds that are financed by income-producing projects and are secured by a specified source of revenue. Municipal issues shall have at least a “BBB” rating by Moody's and/or Standard and Poor’s, or equivalent creditworthiness must be established prior to purchase. All non-rated or private placement securities must be analyzed and approved by the Company’s Credit Department and documented prior to purchase. Obligations of U.S. government agencies and entities. Securities held by the Company are primarily issued by The Federal Home Loan Mortgage Corporation, known as Freddie Mac, and The Federal National Mortgage Association, known as Fannie Mae, which are implicitly guaranteed by the U.S. government and are consistently highly rated by major rating agencies with very little risk to default. U.S. agency residential and commercial mortgage -backed securities and Collateralized Mortgage Obligations. Residential and commercial mortgage -backed securities held by the Company are primarily issued by U.S. government agencies and entities. These securities are either explicitly or implicitly guaranteed by the U.S. government, are consistently highly rated by major rating agencies with very little risk to default. Collateralized mortgage obligations include agency and non-agency residential securities which carry ratings no lower than investment grade “BBB” and pass the federal financial institutions examinations test (Collateral Mortgage Obligation volatility test) at the time of purchase. Corporate securities. Securities held by the Company are primarily comprised of corporate bonds (both senior and subordinated-debt) issued by a firm or public entity which carry ratings no lower than investment grade “BBB” or better by Moody’, Standard and Poor’s, or Kroll rating agencies. All corporate subordinated-debt securities are analyzed and approved by the Company prior to purchase. Allowance for Credit Losses - Available-For-Sale Securities: For available-for-sale debt securities in an unrealized loss position, the Company first assesses whether it intends to sell, or it is more likely than not that it will be required to sell the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the security's amortized cost basis is written down to fair value through income. For available-for-sale debt securities that do not meet the aforementioned criteria, the Company performs a qualitative assessment as to whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, management considers the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded for the credit loss, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that has not been recorded through an allowance for credit losses is recognized in other comprehensive income.
Finance, Loan and Lease Receivables, Held-for-investment, Allowance and Nonperforming Loans, Nonperforming Loans Policy	Mortgage loans that are 180 days past due and commercial loans are charged off to the extent principal or interest is deemed uncollectible. Consumer and credit card loans continue to accrue interest until they are charged off no later than 120 days past due unless the loan is in the process of collection. Past-due status is based on the contractual terms of the loan. In all cases, loans are placed on nonaccrual or charged off at an earlier date if collection of principal or interest is considered doubtful.All interest accrued but not received for loans placed on nonaccrual is reversed against interest income. Interest received on such loans is accounted for on the cash-basis or cost-recovery method, until qualifying for return to accrual. Under the cost-recovery method, interest income is not recognized until the loan balance is reduced to zero. Under the cash-basis method, interest income is recorded when the payment is received in cash. Loans are returned to accrual status when all the principal and interest amounts contractually due are brought current and when, in the opinion of management, the loans are estimated to be fully collectible as to both principal and interest.
Loans and Leases Receivable, Lease Financing, Policy	Loans Held for Investment. Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at amortized cost or principal balance outstanding. Amortized cost is the principal balance outstanding, net of purchase premiums and discounts and deferred loan fees and costs. Loan origination fees, net of certain direct origination costs, are deferred and recognized in interest income using the level-yield method without anticipating prepayments.
Deteriorated Loans Transferred in	Purchased Credit Deteriorated (“PCD”) Loans The Company has loans acquired through acquisitions, some of which have experienced more than insignificant credit deterioration since origination. Loans that meet at least one of the following criteria are considered to have experienced more-than-insignificant credit deterioration since origination at the date of acquisition: 1) have experienced more than one delinquency of more than 60 days or 60+ days as of the acquisition date; 2) have been placed on nonaccrual status at any point since origination; 3) are special mention, substandard, doubtful as of the acquisition date; 4) have a Troubled Debt Restructuring (TDR) status as of the acquisition date; or 5) are in high-risk industries based on macroeconomic conditions and local market conditions of the acquired entity on the acquisition date. PCD loans are recorded at the amount paid for the loan. An allowance for credit losses is determined using the same methodology as other loans held for investment. The initial allowance for credit losses determined on a collective basis is allocated to individual loans. The sum of the loan’s purchase price and allowance for credit losses becomes its initial amortized cost basis. The difference between the initial amortized cost basis and the par value of the loan is a noncredit discount or premium, which is amortized into interest income over the life of the loan. Subsequent changes to the allowance for credit losses are recorded through provision expense.
Off-Balance-Sheet Credit Exposure, Policy	Allowance for Credit Losses on Off-Balance Sheet Credit Exposures. The Company estimates expected credit losses over the contractual period in which the Company is exposed to credit risk via a contractual obligation to extend credit unless that obligation is unconditionally cancellable by the Company. Management considers our unused credit card lines and federal fund lines, extended to others, to be considered unconditionally cancellable. The allowance for credit losses on off-balance sheet credit exposures is adjusted as a provision for credit loss expense. The estimate considers the likelihood that funding will occur and an estimate of expected credit losses on commitments expected to be funded over the estimated life.
Financing Receivable, Allowance for Credit Losses, Policy for Uncollectible Amounts	Allowance for Credit Losses - Loans held for investment The allowance for credit losses is a valuation account that is deducted from the loans’ amortized cost basis to present the net amount expected to be collected over the life of the loans. Loans are charged off against the allowance when management believes the uncollectibility of a loan balance is confirmed. When forecasting expected recoveries, the amounts should not exceed the aggregate of amounts that have previously been or are expected to be charged-off loans. The Company has elected to not forecast recoveries. Management estimates the allowance balance using relevant available information, from internal and external sources, relating to past events, current conditions, and reasonable and supportable forecasts. Historical credit loss experience provides the basis for the estimation of expected credit losses. Adjustments to historical loss information are made for differences in current loan-specific risk characteristics such as differences in underwriting standards, portfolio mix, delinquency level, or term as well as for changes in environmental and economic conditions, such as changes in unemployment rates, property values, or other relevant factors. The allowance for credit losses is measured on a collective (pool) basis when similar risk characteristics exist. The Company applies Probability of Default (PD) and Loss Given Default (LGD) methodologies for all portfolio segments. The Company uses a Transition Matrix (TM) for PD components of the methodology and a historical average for the LGD components of methodology. The PD and LGD is applied to the current principal balance as of the reporting date. The TM determines the PD by tracking the historical movement of loans between loan risk tiers over a defined period of time. The Company currently has 17 portfolio segments for which we track monthly movement between either risk ratings or delinquency band. While the TM functions similarly across all portfolio segments, generally speaking, commercial portfolios use the Company’s risk rating scale and consumer portfolios use the delinquency band. Loans using risk ratings are scored utilizing the Company’s risk rating scale. The risk rating scale is 1-10, with 1 being the best rating, 6 being a pass but on watch, and 7-10 being various stages of criticized loans. Risk ratings 8 or greater and in a non-accrual status are considered in a defaulted state. Loans using delinquency band are measured using a 5-grade band, with 1 being current and 5 being 90 or more days past due. The LGD used as the basis for the estimate of credit losses is comprised of the Company’s historical loss experience from 2008 to the current period, based on a migration analysis of our historical loss experience, designed to account for credit deterioration. The model compares the most recent period losses to prior period defaults to calculate the LGD, which is averaged over the historical observations. Economic scenarios and forecasts along with current portfolio conditions and trends are monitored and accounted for through the Company’s qualitative framework. The Company utilizes a one-year forecast period with immediate reversion to historical loss rates. The Company segments the loan portfolio into pools based on the following risk characteristics: financial asset type, collateral type, loan characteristics, credit characteristics, outstanding loan balances, contractual terms and prepayment assumptions, vintage, industry of borrower and concentrations, and historical or expected credit loss.
Financing Receivable, Held-for-sale	Loans Held for Sale. The Company originates certain loans intended for sale in the secondary market. Conforming agency mortgage production is sold on a servicing retained basis. Certain loans, such as government guaranteed mortgage loans, are sold on a servicing released basis. Residential loans the Company originated with the intent to sell are classified as loans held for sale and recorded at fair value, determined individually, as of the balance sheet date. The loan’s fair value includes the servicing value of the loans as well as any accrued interest. The fair value of loans held for sale are primarily determined based on quoted prices for similar loans in active markets or outstanding commitments from third-party investors. Net unrealized losses, if any, are recorded as a valuation allowance and charged to non-interest income in the consolidated statements of operations. Net gains and losses on loan sales are recorded as a component of non-interest income. Performing residential real estate loans that are held for sale are generally sold with servicing rights retained. Upon the sale of an originated loan, the mortgage servicing right is recorded at its estimated fair value.

Acquisitions (Tables)

Acquisitions (Tables) $ in Millions	12 Months Ended
Acquisitions (Tables) $ in Millions	Dec. 31, 2022 USD ($)
Business Combinations [Abstract]
Schedule of Recognized Identifiable Assets Acquired and Liabilities Assumed	The following table provides the purchase price allocation as of the acquisition date and the Great Western assets acquired and liabilities assumed at their estimated fair value as of the acquisition date as amended for measurement period adjustments as of December 31, 2022. We recorded the estimate of fair value based on valuations at the acquisition date. The excess value of the consideration paid over the fair value of assets acquired and liabilities assumed was recorded as goodwill. The purchase price allocation resulted in goodwill of $479.3 million, of which $31.7 million is deductible for income tax purposes. Goodwill resulting from the acquisition was allocated to the Company’s one operating segment, community banking, and consists largely of the synergies and economies of scale expected from combining the operations of Great Western and the Company. All amounts reported were finalized during the fourth quarter of 2022. As of February 1, 2022 Assets acquired: Cash and cash equivalents $ 2,006.9 Investment securities 2,699.0 Securities purchased under agreement to resell 101.1 Loans held for sale 217.0 Loans held for investment 7,705.0 Allowance for credit losses (59.5) Premises and equipment, including right of use lease assets 144.7 Other real estate owned (“OREO”) 15.8 Company owned life insurance 186.6 Core deposit intangibles 50.1 Customer relationship intangible 22.8 Mortgage servicing rights 1.3 Deferred tax assets, net 60.2 Other assets 200.8 Total assets acquired 13,351.8 Liabilities assumed: Deposits 11,688.0 Securities sold under repurchase agreements 74.0 Accrued expenses and other liabilities 110.4 FHLB advances 122.9 Subordinated debt 36.4 Subordinated debentures held by subsidiary trusts 76.1 Total liabilities assumed 12,107.8 Net assets acquired $ 1,244.0 Consideration paid: Class A common stock 1,723.3 Total consideration paid (1) $ 1,723.3 Goodwill $ 479.3 (1) Includes $13 thousand of cash paid in lieu of fractional shares.
Change in goodwill	$ (36.7)
Financing Receivable, Purchased	The non-credit discount or premium, after the adjustment for the allowance for credit losses, is accreted to interest income using the interest method based on the effective interest rate determined after the adjustment for credit losses at the adoption date. Information regarding loans acquired at the acquisition date as amended for measurement period adjustments as of December 31, 2022 were as follows: (In millions) PCD loans: Unpaid principal balance $ 979.2 Principal amounts previously written off by GWB (238.7) Interest applied to principal by GWB (18.1) Adjusted unpaid principal balance 722.4 Credit discount (69.2) Discount attributable to other factors (29.9) Fair value 623.3 Allowance for credit losses 59.5 Amortized cost basis 682.8 Non-PCD loans: Unpaid principal balance 7,107.9 Credit discount (1) (76.5) Non-credit discount (9.2) Fair value 7,022.2 Amortized cost basis $ 7,705.0 (1) Represents the best estimate of the contractual cash flows not expected to be collected as of the acquisition date.
Business Acquisition, Pro Forma Information	The following table presents certain pro forma financial information for the years ended December 31, 2022 and 2021 as if GWB had been acquired on January 1, 2021. This pro forma information combines the historical results of GWB with the Company’s consolidated historical results and includes certain adjustments reflecting the estimated impact of certain fair value adjustments for the respective periods. The pro forma information is not indicative of what would have occurred had the acquisition occurred at the beginning of the year prior to the acquisition. The pro forma information does not consider any changes to the provision for credit losses resulting from recording loan assets at fair value, cost savings, or business synergies. As a result, actual amounts would have differed from the pro forma information presented, and the differences could be significant. December 31, 2022 2021 Total revenues $ 1,223.3 $ 1,200.9 Net income $ 351.6 $ 243.3 Earnings per common share (Basic) $ 3.28 $ 2.24 Earnings per common share (Diluted) $ 3.28 $ 2.24
Change in Goodwill	As of December 31, 2022, the Company recorded measurement period adjustments to the fair value marks as indicated in the table below. These adjustments resulted in a net decrease to goodwill of $36.7 million from the March 31, 2022 reported balances. The related impact to net income that would have been recognized in previous periods if the adjustments were recognized as of the acquisition date was not material to the consolidated financial statements. Asset adjustments: Loans held for sale $ 35.1 Loans held for investment (8.4) Allowance for credit losses 24.8 Premises and equipment 0.6 Core deposit intangibles 1.0 Deferred tax assets (15.9) Other assets 2.8 Total asset adjustments $ 40.0 Liability adjustments: Accrued expenses and other liabilities $ 3.3 Total liability adjustments $ 3.3 Net adjustment to goodwill $ (36.7)

Goodwill and Core Deposit Int_2

Goodwill and Core Deposit Intangibles (Tables)	12 Months Ended
Goodwill and Core Deposit Intangibles (Tables)	Dec. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Change in Carrying Amount of Goodwill	The following table details changes in the recorded amount of goodwill as of the dates indicated: Year Ended December 31, 2022 2021 Net carrying value at beginning of period $ 621.6 $ 621.6 Additions to goodwill from acquisition 479.3 — Net carrying value at end of period $ 1,100.9 $ 621.6 The Company performed its annual impairment assessment as of July 1, 2022 and 2021 and concluded that there was no impairment to goodwill. In addition, there were no events or circumstances that occurred during the second half of 2022 that would more-likely-than-not reduce the fair value of the Company’s reporting unit below its carrying value. The Company did not perform interim impairment testing as of December 31, 2022.
Schedule of Activity of Identifiable Core Deposit Intangibles	Other intangible assets are comprised of core deposit intangibles (“CDI”) and other customer relationship intangibles (“OCRI”) and amounted to the following at December 31, 2022 and 2021: December 31, 2022 CDI OCRI Total Gross other intangible assets, at beginning of the period $ 106.0 $ — $ 106.0 Amounts established through acquisition 50.1 22.8 72.9 Reductions due to sale of health savings accounts (1.4) — (1.4) Accumulated amortization (78.8) (1.7) (80.5) Net other intangible assets, end of period $ 75.9 $ 21.1 $ 97.0 December 31, 2021 Gross other intangible assets, at beginning of the period $ 106.0 $ — $ 106.0 Accumulated amortization (64.7) — (64.7) Net other intangible assets, end of period $ 41.3 $ — $ 41.3
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The following table provides the estimated aggregate future amortization expense of other intangible assets: Years ending December 31, CDI OCRI Total 2023 $ 13.7 $ 1.9 $ 15.6 2024 12.7 1.9 14.6 2025 11.8 1.9 13.7 2026 10.9 1.9 12.8 2027 8.2 1.9 10.1 Thereafter 18.6 11.6 30.2 Total $ 75.9 $ 21.1 $ 97.0

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
Investment Securities (Tables)	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Amortized Cost and Approximate Fair Values of Investment Securities	The amortized cost and approximate fair values of investment securities are summarized as follows: December 31, 2022 Amortized Gross Gross Estimated Available-for-Sale U.S. Treasury notes $ 675.1 $ 2.1 $ (34.5) $ 642.7 State, county, and municipal securities 314.3 — (50.6) 263.7 Obligations of U.S. government agencies 216.2 — (17.3) 198.9 U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 4,685.5 0.2 (426.0) 4,259.7 Private mortgage-backed securities 264.9 — (36.9) 228.0 Collateralized loan obligations 1,145.2 — (33.6) 1,111.6 Corporate Securities 272.3 — (30.8) 241.5 Total $ 7,573.5 $ 2.3 $ (629.7) $ 6,946.1 December 31, 2022 Amortized Allowance for Credit Losses Net Carrying Amount Gross Unrealized Gains Gross Estimated Held-to Maturity U.S. Treasury notes $ 396.6 $ — $ 396.6 $ — $ (10.2) $ 386.4 State, county, and municipal securities 181.2 (0.1) 181.1 0.2 (31.6) 149.7 Obligations of U.S. government agencies 351.7 — 351.7 — (49.6) 302.1 U.S agency residential & commercial mortgage-backed securities & collateralized mortgage obligations (1) 2,444.1 — 2,444.1 0.2 (301.6) 2,142.7 Corporate securities 80.1 (1.8) 78.3 — (7.0) 71.3 Total $ 3,453.7 $ (1.9) $ 3,451.8 $ 0.4 $ (400.0) $ 3,052.2 (1) Amortized cost presented above include $20.2 million of unamortized losses and $14.2 million of unamortized gains related to the 2021 and 2022 transfer of securities from available-for-sale to held-to-maturity. December 31, 2021 Amortized Gross Gross Estimated Available-for-Sale U.S. Treasury notes $ 697.6 $ — $ (12.9) $ 684.7 State, county, and municipal securities 434.7 2.1 (9.3) 427.5 Obligations of U.S. government agencies 356.0 0.1 (9.2) 346.9 U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 2,027.3 14.1 (23.3) 2,018.1 Private mortgage-backed securities 174.4 0.1 (1.1) 173.4 Collateralized loan obligation 898.2 1.2 — 899.4 Corporate Securities 271.1 3.0 (3.6) 270.5 Total $ 4,859.3 $ 20.6 $ (59.4) $ 4,820.5 December 31, 2021 Amortized Allowance for Credit Losses Net Carrying Amount Gross Gross Estimated Held-to Maturity State, county, and municipal securities $ 67.6 $ — $ 67.6 $ 2.0 $ (0.4) $ 69.2 U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 1,609.0 — 1,609.0 13.2 (35.3) 1,586.9 Corporate securities 11.0 — 11.0 0.4 — 11.4 Total $ 1,687.6 $ — $ 1,687.6 $ 15.6 $ (35.7) $ 1,667.5 (1) Amortized cost presented above include $20.1 million of unamortized gains in U.S. agency residential and commercial mortgage-backed securities and collateralized mortgage obligations related to the 2021 transfer of securities from available-for-sale to held-to-maturity.
Gross Unrealized Losses and Fair Values of Investment Securities	The following tables show the gross unrealized losses and fair values of investment securities, aggregated by investment category, and the length of time individual investment securities have been in a continuous unrealized loss position, as of December 31, 2022 and 2021. Less than 12 Months 12 Months or More Total December 31, 2022 Fair Gross Fair Gross Fair Gross Available-for-Sale U.S. Treasury notes $ 168.8 $ (4.7) $ 170.4 $ (29.8) $ 339.2 $ (34.5) State, county, and municipal securities 104.9 (9.0) 146.1 (41.6) 251.0 (50.6) Obligations of U.S. government agencies 152.2 (10.1) 46.1 (7.2) 198.3 (17.3) U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 3,299.7 (262.3) 948.4 (163.7) 4,248.1 (426.0) Private mortgage-backed securities 133.1 (19.1) 94.9 (17.8) 228.0 (36.9) Collateralized loan obligations 1,082.6 (33.1) 28.9 (0.5) 1,111.5 (33.6) Corporate securities 130.6 (8.3) 110.8 (22.5) 241.4 (30.8) Total $ 5,071.9 $ (346.6) $ 1,545.6 $ (283.1) $ 6,617.5 $ (629.7) Less than 12 Months 12 Months or More Total December 31, 2022 Fair Gross Fair Gross Fair Gross Held-to-Maturity U.S. Treasury notes $ 386.4 $ (10.2) $ — $ — $ 386.4 $ (10.2) State, county and municipal securities 33.8 (4.0) 96.7 (27.6) 130.5 (31.6) Obligations of U.S. government agencies 86.1 (9.9) 216.0 (39.7) 302.1 (49.6) U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 1,349.4 (156.1) 762.5 (145.5) 2,111.9 (301.6) Corporate securities 68.2 (7.0) — — 68.2 (7.0) Total $ 1,923.9 $ (187.2) $ 1,075.2 $ (212.8) $ 2,999.1 $ (400.0) Less than 12 Months 12 Months or More Total December 31, 2021 Fair Gross Fair Gross Fair Gross Available-for-Sale U.S. Treasury notes $ 684.7 $ (12.9) $ — $ — $ 684.7 $ (12.9) State, county, and municipal securities 278.7 (9.1) 5.0 (0.2) 283.7 (9.3) Obligations of U.S. government agencies 297.0 (8.9) 16.4 (0.3) 313.4 (9.2) U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 1,262.8 (23.0) 26.4 (0.3) 1,289.2 (23.3) Private mortgage-backed securities 127.2 (1.1) — — 127.2 (1.1) Corporate securities 109.9 (3.3) 20.9 (0.3) 130.8 (3.6) Total $ 2,760.3 $ (58.3) $ 68.7 $ (1.1) $ 2,829.0 $ (59.4) Less than 12 Months 12 Months or More Total December 31, 2021 Fair Gross Fair Gross Fair Gross Held-to-Maturity State, county and municipal securities $ 29.0 $ (0.4) $ — $ — $ 29.0 $ (0.4) U.S. agency residential mortgage-backed 1,038.7 (35.3) — — 1,038.7 (35.3) Total $ 1,067.7 $ (35.7) $ — $ — $ 1,067.7 $ (35.7)
Debt Securities, Held-to-maturity, Allowance for Credit Loss	The following table presents the activity in the allowance for credit losses related to held-to-maturity securities classified as corporate and state, county, and municipal securities: Year Ended December 31, 2022 2021 2020 Beginning balance $ — $ — $ — Provision for credit loss expense 1.9 — — Ending balance of allowance for credit losses $ 1.9 $ — $ —
Debt Securities, Held-to-maturity, Credit Quality Indicator	The following table summarizes the credit quality indicators of held-to-maturity securities at amortized cost for the periods indicated: December 31, 2022 AAA AA A BBB BB Not Rated Total U.S. Treasury notes $ 396.6 $ — $ — $ — $ — $ — $ 396.6 State, county, and municipal securities 68.3 92.8 11.5 — — 8.6 181.2 Obligations of U.S. government agencies 351.7 — — — — — 351.7 U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations FNMA/FHLMC 2,233.6 — — — — — 2,233.6 GNMA 210.5 — — — — — 210.5 Corporate securities — — — 65.1 10.0 5.0 80.1 Total $ 3,260.7 $ 92.8 $ 11.5 $ 65.1 $ 10.0 $ 13.6 $ 3,453.7 December 31, 2021 AAA AA A BBB Not Rated Total State, county, and municipal securities $ 17.2 $ 31.6 $ 14.7 $ — $ 4.1 $ 67.6 U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations FNMA/FHLMC 1,439.1 — — — — 1,439.1 GNMA 169.9 — — — — 169.9 Corporate securities — — 4.0 7.0 — 11.0 Total $ 1,626.2 $ 31.6 $ 18.7 $ 7.0 $ 4.1 $ 1,687.6
Maturities of Investment Securities	Available-for-Sale Held-to-Maturity December 31, 2022 Amortized Estimated Amortized Estimated Within one year $ 48.8 $ 48.1 $ 2.5 $ 2.5 After one year but within five years 1,478.9 1,419.8 607.6 581.6 After five years but within ten years 1,750.0 1,564.3 732.7 639.5 After ten years 4,295.8 3,913.9 2,110.9 1,828.6 Total $ 7,573.5 $ 6,946.1 $ 3,453.7 $ 3,052.2

Loans Held for Sale (Tables)

Loans Held for Sale (Tables)	12 Months Ended
Loans Held for Sale (Tables)	Dec. 31, 2022
Loans Held for Sale [Abstract]
Loans Held for Sale (Table)	The following table presents loans held for sale by segment for the dates indicated: December 31, December 31, Loans Held for Sale: Agricultural $ 62.5 $ — Commercial construction 10.5 — Residential real estate 6.9 30.1 Total loans held for sale $ 79.9 $ 30.1 On February 1, 2022, the Company acquired $2.1 million of held for sale residential real estate loans. In conjunction with the acquisition of GWB, the Company reclassified certain agricultural and commercial loans to loans held for sale from loans held for investment due to management’s intent and decision to sell the loans. The table below presents the non-residential held for sale loan activity for the 2022 period: Agricultural Commercial Construction Commercial Beginning balance $ — $ — $ — GWB loans held for investment transferred to loans held for sale on acquisition date 190.9 — 24.0 Loans held for sale transferred to loans held for investment (19.8) — — Repayments and discounted pay-offs (110.1) — (0.6) Loan disposals — — (23.4) Loans held for investment transferred to loans held for sale — 12.4 — Increase (decrease) in estimated fair value of the loans 1.5 (1.9) — Ending balance $ 62.5 $ 10.5 $ —

Loans Held for Investment (Tabl

Loans Held for Investment (Tables)	12 Months Ended
Loans Held for Investment (Tables)	Dec. 31, 2022
Receivables [Abstract]
Schedule of Loans by Class	The following table presents loans by segment as of the dates indicated: 2022 2021 Real estate loans: Commercial $ 8,528.6 $ 3,971.5 Construction loans: Land acquisition & development 386.2 247.8 Residential 516.2 262.0 Commercial 1,042.0 498.0 Total construction loans 1,944.4 1,007.8 Residential 2,188.3 1,538.2 Agricultural 794.9 213.9 Total real estate loans 13,456.2 6,731.4 Consumer loans: Indirect 829.7 737.6 Direct and advance lines 152.9 129.2 Credit card 75.9 64.9 Total consumer loans 1,058.5 931.7 Commercial 2,882.6 1,475.5 Agricultural 708.3 203.9 Other, including overdrafts 9.2 1.5 Loans held for investment 18,114.8 9,344.0 Deferred loan fees and costs (15.6) (12.3) Loans held for investment, net of deferred fees and costs 18,099.2 9,331.7 Allowance for credit losses (220.1) (122.3) Net loans held for investment $ 17,879.1 $ 9,209.4
Schedule of Allowance for Loan Losses by Portfolio Segment	The following tables represent, by loan portfolio segment, the activity in the allowance for credit losses for loans held for investment: December 31, 2022 Beginning Balance ACL Recorded for PCD loans Provision for (reversal of) Credit Losses (2) Loans Charged-Off Recoveries Collected Ending Balance Allowance for credit losses (1) Real estate: Commercial real estate: Non-owner occupied $ 17.3 $ 17.2 $ (4.2) $ (3.5) $ 0.4 $ 27.2 Owner occupied 13.3 9.5 (2.7) (2.5) 1.9 19.5 Multi-family 13.3 10.9 8.7 (5.7) 0.7 27.9 Total commercial real estate 43.9 37.6 1.8 (11.7) 3.0 74.6 Construction: Land acquisition & development 0.5 3.4 (0.4) (2.6) 0.4 1.3 Residential construction 2.4 — 1.1 — 0.1 3.6 Commercial construction 6.0 0.2 31.6 (6.6) — 31.2 Total construction 8.9 3.6 32.3 (9.2) 0.5 36.1 Residential real estate: Residential 1-4 family 13.4 0.1 6.9 (0.2) 0.3 20.5 Home equity and HELOC 1.2 — — (0.1) 0.5 1.6 Total residential real estate 14.6 0.1 6.9 (0.3) 0.8 22.1 Agricultural real estate 1.9 2.3 1.5 (0.2) 0.4 5.9 Total real estate 69.3 43.6 42.5 (21.4) 4.7 138.7 Consumer: Indirect 14.3 — 2.7 (4.0) 2.3 15.3 Direct and advance lines 4.6 — 2.2 (3.7) 2.1 5.2 Credit card 2.2 — 2.4 (2.4) 0.6 2.8 Total consumer 21.1 — 7.3 (10.1) 5.0 23.3 Commercial: Commercial and floor plans 27.1 11.2 15.1 (6.6) 2.2 49.0 Commercial purpose secured by 1-4 family 4.4 0.2 1.2 (0.2) 0.1 5.7 Credit card 0.1 — 1.4 (1.3) — 0.2 Total commercial 31.6 11.4 17.7 (8.1) 2.3 54.9 Agricultural: Agricultural 0.3 4.5 0.9 (5.4) 2.9 3.2 Total agricultural 0.3 4.5 0.9 (5.4) 2.9 3.2 Total allowance for credit losses $ 122.3 $ 59.5 $ 68.4 $ (45.0) $ 14.9 $ 220.1 (1) Amounts presented are exclusive of the allowance for credit losses related to unfunded commitments which are included in Note “Financial Instruments with Off-Balance Sheet Risk” included in this report. (2) Amounts include $68.3 million related to the acquired GWB non-PCD loans. December 31, 2021 Beginning Balance Provision for (reversal of) Credit Loss Loans Charged-Off Recoveries Collected Ending Balance Allowance for credit losses (1) Real estate: Commercial real estate: Non-owner occupied $ 25.5 $ (8.3) $ — $ 0.1 $ 17.3 Owner occupied 18.3 (2.7) (2.3) — 13.3 Multi-family 11.0 2.3 — — 13.3 Total commercial real estate 54.8 (8.7) (2.3) 0.1 43.9 Construction: Land acquisition & development 1.3 (0.1) (1.2) 0.5 0.5 Residential construction 1.6 0.9 (0.1) — 2.4 Commercial construction 7.3 (1.3) (0.1) 0.1 6.0 Total construction 10.2 (0.5) (1.4) 0.6 8.9 Residential real estate: Residential 1-4 family 11.4 2.0 — — 13.4 Home equity and HELOC 1.4 (0.4) (0.1) 0.3 1.2 Total residential real estate 12.8 1.6 (0.1) 0.3 14.6 Agricultural real estate 2.7 (0.1) (0.7) — 1.9 Total real estate 80.5 (7.7) (4.5) 1.0 69.3 Consumer: Indirect 16.7 (1.4) (3.5) 2.5 14.3 Direct and advance lines 4.6 1.7 (2.9) 1.2 4.6 Credit card 2.6 0.6 (1.8) 0.8 2.2 Total consumer 23.9 0.9 (8.2) 4.5 21.1 Commercial: Commercial and floor plans 34.2 (7.3) (3.0) 3.2 27.1 Commercial purpose secured by 1-4 family 4.7 (0.5) (0.3) 0.5 4.4 Credit card 0.3 0.1 (0.4) 0.1 0.1 Total commercial 39.2 (7.7) (3.7) 3.8 31.6 Agricultural: Agricultural 0.7 (0.2) (0.2) — 0.3 Total agricultural 0.7 (0.2) (0.2) — 0.3 Total allowance for credit losses $ 144.3 $ (14.7) $ (16.6) $ 9.3 $ 122.3 (1) Amounts presented are exclusive of the allowance for credit losses related to unfunded commitments which are included in Note “Financial Instruments with Off-Balance Sheet Risk” included in this report. December 31, 2020 Beginning Balance Initial Impact of Adopting ASC 326 Provision for (reversal of) Credit Loss Loans Charged-Off Recoveries Collected Ending Balance Allowance for credit losses (1) Real estate: Commercial real estate: Non-owner occupied $ 8.8 $ 4.9 $ 11.7 $ — $ 0.1 $ 25.5 Owner occupied 10.0 3.5 5.0 (0.4) 0.2 18.3 Multi-family 0.7 6.9 3.4 — — 11.0 Total commercial real estate 19.5 15.3 20.1 (0.4) 0.3 54.8 Construction: Land acquisition & development 1.9 (0.1) (0.4) (0.5) 0.4 1.3 Residential construction 1.5 (0.9) 1.0 — — 1.6 Commercial construction 2.7 1.3 3.3 — — 7.3 Total construction 6.1 0.3 3.9 (0.5) 0.4 10.2 Residential real estate: Residential 1-4 family 1.8 10.6 (1.1) — 0.1 11.4 Home equity and HELOC 1.0 0.5 (0.4) — 0.3 1.4 Total residential real estate 2.8 11.1 (1.5) — 0.4 12.8 Agricultural real estate 0.5 1.8 0.4 — — 2.7 Total real estate 28.9 28.5 22.9 (0.9) 1.1 80.5 Consumer: Indirect 4.5 8.8 5.4 (4.1) 2.1 16.7 Direct and advance lines 2.9 3.0 1.6 (3.9) 1.0 4.6 Credit card 2.5 0.3 1.8 (2.8) 0.8 2.6 Total consumer 9.9 12.1 8.8 (10.8) 3.9 23.9 Commercial: Commercial and floor plans 25.5 (5.1) 20.4 (8.0) 1.4 34.2 Commercial purpose secured by 1-4 family 5.9 (3.8) 2.5 (0.1) 0.2 4.7 Credit card 1.2 (1.1) 1.1 (1.0) 0.1 0.3 Total commercial 32.6 (10.0) 24.0 (9.1) 1.7 39.2 Agricultural: Agricultural 1.6 (0.6) (0.2) (0.1) — 0.7 Total agricultural 1.6 (0.6) (0.2) (0.1) — 0.7 Total allowance for credit losses $ 73.0 $ 30.0 $ 55.5 $ (20.9) $ 6.7 $ 144.3 (1) Amounts presented are exclusive of the allowance for credit losses related to unfunded commitments which are included in Note “Financial Instruments with Off-Balance Sheet Risk” included in this report.
Schedule of Recorded Investment in Impaired Loans	The following table presents the amortized cost basis of collateral-dependent loans by class of loans as of the dates indicated: As of December 31, 2022 As of December 31, 2021 Collateral Type Business Assets Real Property Other Total Business Assets Real Property Other Total Real estate $ 1.9 $ 25.3 $ — $ 27.2 $ 1.2 $ 7.0 $ — $ 8.2 Commercial 3.1 1.5 — 4.6 1.8 1.0 — 2.8 Agricultural 2.1 5.2 — 7.3 — 0.7 — 0.7 Total collateral-dependent $ 7.1 $ 32.0 $ — $ 39.1 $ 3.0 $ 8.7 $ — $ 11.7
Schedule of Recorded Investment in Past Due Loans by Class	Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Loans classified in the following table as greater than 90 days past due continue to accrue interest. The following tables present the contractual aging of the Company’s recorded amortized cost basis in loans by portfolio as of the dates indicated. Total Loans 30 - 59 60 - 89 > 90 30 or More Days Days Days Days Current Non-accrual Total As of December 31, 2022 Past Due Past Due Past Due Past Due Loans Loans (1) Loans Real estate Commercial $ 5.6 $ 0.8 $ 1.1 $ 7.5 $ 8,501.5 $ 19.6 $ 8,528.6 Construction: Land acquisition & development 1.8 — 0.6 2.4 380.1 3.7 386.2 Residential 1.1 — — 1.1 515.1 — 516.2 Commercial 7.5 0.6 — 8.1 1,033.9 — 1,042.0 Total construction loans 10.4 0.6 0.6 11.6 1,929.1 3.7 1,944.4 Residential 9.9 2.1 1.2 13.2 2,168.7 6.4 2,188.3 Agricultural 1.1 6.1 — 7.2 780.1 7.6 794.9 Total real estate loans 27.0 9.6 2.9 39.5 13,379.4 37.3 13,456.2 Consumer: Indirect consumer 9.3 2.4 0.6 12.3 814.7 2.7 829.7 Other consumer 0.8 0.3 0.1 1.2 151.4 0.3 152.9 Credit card 0.8 0.4 0.6 1.8 74.1 — 75.9 Total consumer loans 10.9 3.1 1.3 15.3 1,040.2 3.0 1,058.5 Commercial 7.1 1.7 2.1 10.9 2,861.5 10.2 2,882.6 Agricultural 0.8 2.2 0.1 3.1 696.5 8.7 708.3 Other, including overdrafts — — — — 9.2 — 9.2 Loans held for investment $ 45.8 $ 16.6 $ 6.4 $ 68.8 $ 17,986.8 $ 59.2 $ 18,114.8 Total Loans 30 - 59 60 - 89 > 90 30 or More Days Days Days Days Current Non-accrual Total As of December 31, 2021 Past Due Past Due Past Due Past Due Loans Loans (1) Loans Real estate Commercial $ 1.1 $ 1.0 $ 0.6 $ 2.7 $ 3,960.8 $ 8.0 $ 3,971.5 Construction: Land acquisition & development 0.2 — — 0.2 246.9 0.7 247.8 Residential 4.2 — — 4.2 257.8 — 262.0 Commercial — — — — 498.0 — 498.0 Total construction loans 4.4 — — 4.4 1,002.7 0.7 1,007.8 Residential 3.0 0.8 0.1 3.9 1,531.4 2.9 1,538.2 Agricultural 1.9 0.2 — 2.1 206.9 4.9 213.9 Total real estate loans 10.4 2.0 0.7 13.1 6,701.8 16.5 6,731.4 Consumer: Indirect consumer 5.1 1.4 0.4 6.9 729.0 1.7 737.6 Other consumer 0.5 0.2 0.1 0.8 128.3 0.1 129.2 Credit card 0.6 0.2 0.5 1.3 63.6 — 64.9 Total consumer loans 6.2 1.8 1.0 9.0 920.9 1.8 931.7 Commercial 4.9 0.7 1.1 6.7 1,463.8 5.0 1,475.5 Agricultural 0.7 — — 0.7 201.6 1.6 203.9 Other, including overdrafts — — — — 1.5 — 1.5 Loans held for investment $ 22.2 $ 4.5 $ 2.8 $ 29.5 $ 9,289.6 $ 24.9 $ 9,344.0 (1) As of December 31, 2022 and 2021, none of our non-accrual loans were earning interest income. Additionally, no material interest income was recognized on non-accrual loans at December 31, 2022 and 2021, respectively and $1.5 million accrued interest was reversed at December 31, 2022.
Schedule of Loans Renegotiated in Troubled Debt Restructurings	The Company had $71.7 million of new TDRs during the period ended December 31, 2022 and no material new TDRs during the periods ending December 31, 2021 and 2020. The following table presents information of the Company’s TDRs that occurred for the period indicated: Number of Notes Type of Concession Principal Balance at Restructure December 31, 2022 Interest only period Extension of term or amortization schedule Interest rate adjustment Other (1) Commercial real estate 4 $ 3.2 $ 4.2 $ — $ 46.3 $ 53.7 Residential real estate 2 — 0.6 — — 0.6 Agriculture real estate 2 — 9.0 — — 9.0 Commercial 3 — 1.9 — 0.6 2.5 Agriculture 1 — — — 5.9 5.9 Total loans restructured during period 12 $ 3.2 $ 15.7 $ — $ 52.8 $ 71.7 (1) Other includes concessions that reduce or defer payments for a specified period of time and/or concessions that do not fit into other designated categories.
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period	The following table reconciles the par value, or initial amortized cost, of PCD loans acquired in the GWB acquisition as of the date of the acquisition with the purchase price (or initial fair value of the loans) as amended for measurement period adjustments as of December 31, 2022: Purchase price (initial fair value) $ 623.3 Allowance for credit losses (1) 298.2 Discount attributable to other factors (2) 57.7 Par value (unpaid principal balance) $ 979.2 (1) For acquired PCD loans, an allowance of $298.2 million was required with a corresponding increase to the amortized cost basis as of the acquisition date. For PCD loans where all or a portion of the loan balance had been previously written-off by GWB, or would be subject to write-off under the Company’s charge-off policy, a CECL allowance of $238.7 million, included as part of the grossed-up loan balance at acquisition was immediately written-off. The net impact to the allowance for PCD assets on the acquisition date was $59.5 million. (2) Non-credit discount includes the difference between the amortized cost basis and the unpaid principal balance of $39.6 million established on GWB PCD loans acquired and interest applied to principal of $18.1 million.
Schedule of Recorded Investment in Criticized Loans by Class and Credit Quality Indicator	The Company evaluates the credit quality and loan performance for the allowance for credit loan losses of the following segments based on the aforementioned risk scale for the periods indicated: December 31, 2022 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2022 2021 2020 2019 2018 Prior Revolving Loans Amortized Cost Basis Total Commercial real estate non-owner occupied: Pass $ 1,162.6 $ 861.3 $ 661.1 $ 467.6 $ 241.5 $ 890.4 $ 29.2 $ 4,313.7 Special mention 1.0 6.8 2.3 4.6 — 7.4 — 22.1 Substandard 0.1 13.9 10.8 18.2 19.6 9.8 — 72.4 Total $ 1,163.7 $ 882.0 $ 674.2 $ 490.4 $ 261.1 $ 907.6 $ 29.2 $ 4,408.2 Commercial real estate owner occupied: Pass $ 793.0 $ 718.7 $ 533.9 $ 266.3 $ 165.8 $ 551.3 $ 18.2 $ 3,047.2 Special mention 10.9 14.2 12.3 6.1 5.6 5.5 1.1 55.7 Substandard 8.4 3.0 2.3 8.9 8.5 17.2 0.5 48.8 Doubtful 0.4 1.4 — — — — — 1.8 Total $ 812.7 $ 737.3 $ 548.5 $ 281.3 $ 179.9 $ 574.0 $ 19.8 $ 3,153.5 Commercial multi-family: Pass $ 369.2 $ 204.9 $ 189.0 $ 52.1 $ 35.0 $ 113.7 $ 1.0 $ 964.9 Special mention — — — — — 1.7 — 1.7 Substandard — — — — — 0.3 — 0.3 Total $ 369.2 $ 204.9 $ 189.0 $ 52.1 $ 35.0 $ 115.7 $ 1.0 $ 966.9 Land, acquisition and development: Pass $ 152.5 $ 114.4 $ 29.5 $ 17.0 $ 10.9 $ 28.4 $ 22.2 $ 374.9 Special mention 6.7 — — — 0.2 0.3 — 7.2 Substandard — 0.3 0.2 — — 0.4 — 0.9 Doubtful — 3.2 — — — — — 3.2 Total $ 159.2 $ 117.9 $ 29.7 $ 17.0 $ 11.1 $ 29.1 $ 22.2 $ 386.2 Residential construction: Pass $ 118.4 $ 119.9 $ 0.4 $ 0.3 $ 0.4 $ 5.8 $ 270.1 $ 515.3 Substandard — 0.5 — — — 0.4 — 0.9 Total $ 118.4 $ 120.4 $ 0.4 $ 0.3 $ 0.4 $ 6.2 $ 270.1 $ 516.2 Commercial construction: Pass $ 442.7 $ 374.8 $ 89.7 $ 45.9 $ 0.4 $ — $ 10.6 $ 964.1 Special mention 2.3 — 23.1 — — — 11.3 36.7 Substandard 16.8 24.4 — — — — — 41.2 Total $ 461.8 $ 399.2 $ 112.8 $ 45.9 $ 0.4 $ — $ 21.9 $ 1,042.0 Agricultural real estate: Pass $ 180.0 $ 172.8 $ 109.5 $ 64.8 $ 46.6 $ 105.1 $ 31.4 $ 710.2 Special mention 22.4 0.7 1.2 2.6 10.0 3.2 11.0 51.1 Substandard 1.8 12.3 3.5 0.6 2.7 11.3 0.1 32.3 Doubtful — — 1.3 — — — — 1.3 Total $ 204.2 $ 185.8 $ 115.5 $ 68.0 $ 59.3 $ 119.6 $ 42.5 $ 794.9 Commercial and floor plans: Pass $ 501.7 $ 358.9 $ 214.4 $ 124.3 $ 120.3 $ 171.1 $ 631.6 $ 2,122.3 Special mention 15.9 6.8 1.3 4.4 0.9 4.9 18.5 52.7 Substandard 9.8 3.3 3.7 3.4 3.2 2.1 47.2 72.7 Doubtful 0.3 1.3 — — — — 0.1 1.7 Total $ 527.7 $ 370.3 $ 219.4 $ 132.1 $ 124.4 $ 178.1 $ 697.4 $ 2,249.4 December 31, 2022 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2022 2021 2020 2019 2018 Prior Revolving Loans Amortized Cost Basis Total Commercial purpose secured by 1-4 family: Pass $ 191.7 $ 134.5 $ 69.8 $ 30.4 $ 29.9 $ 39.5 $ 28.9 $ 524.7 Special mention 0.1 1.2 2.1 0.2 1.4 0.2 — 5.2 Substandard 0.2 0.3 0.1 0.3 0.9 1.2 — 3.0 Total $ 192.0 $ 136.0 $ 72.0 $ 30.9 $ 32.2 $ 40.9 $ 28.9 $ 532.9 Agricultural: Pass $ 127.2 $ 59.7 $ 31.8 $ 10.6 $ 8.6 $ 3.1 $ 375.1 $ 616.1 Special mention 26.1 2.8 0.4 1.0 0.3 — 26.2 56.8 Substandard 22.8 4.6 2.8 0.6 1.2 0.2 0.8 33.0 Doubtful — 0.5 — — — — — 0.5 Total $ 176.1 $ 67.6 $ 35.0 $ 12.2 $ 10.1 $ 3.3 $ 402.1 $ 706.4 December 31, 2021 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2021 2020 2019 2018 2017 Prior Revolving Loans Amortized Cost Basis Total Commercial real estate non-owner occupied: Pass $ 507.9 $ 452.2 $ 237.9 $ 150.4 $ 76.3 $ 409.0 $ 15.3 $ 1,849.0 Special mention 0.2 3.1 2.1 — — 3.6 — 9.0 Substandard 3.9 15.3 2.3 0.7 1.0 12.4 — 35.6 Total $ 512.0 $ 470.6 $ 242.3 $ 151.1 $ 77.3 $ 425.0 $ 15.3 $ 1,893.6 Commercial real estate owner occupied: Pass $ 452.7 $ 314.9 $ 235.0 $ 151.0 $ 94.5 $ 322.5 $ 14.2 $ 1,584.8 Special mention 1.3 3.2 1.5 7.4 3.5 13.8 — 30.7 Substandard 3.8 4.3 4.7 5.4 2.7 20.3 — 41.2 Total $ 457.8 $ 322.4 $ 241.2 $ 163.8 $ 100.7 $ 356.6 $ 14.2 $ 1,656.7 Commercial multi-family: Pass $ 129.1 $ 118.6 $ 43.9 $ 15.4 $ 36.0 $ 76.7 $ 1.5 $ 421.2 Total $ 129.1 $ 118.6 $ 43.9 $ 15.4 $ 36.0 $ 76.7 $ 1.5 $ 421.2 Land, acquisition and development: Pass $ 113.0 $ 41.5 $ 34.2 $ 14.8 $ 19.8 $ 20.8 $ 1.2 $ 245.3 Special mention — 0.1 — — 0.1 0.3 — 0.5 Substandard 0.8 0.2 — 0.6 0.3 0.1 — 2.0 Total $ 113.8 $ 41.8 $ 34.2 $ 15.4 $ 20.2 $ 21.2 $ 1.2 $ 247.8 Residential construction: Pass $ 112.4 $ 7.0 $ 13.7 $ 0.9 $ — $ — $ 127.2 $ 261.2 Substandard — 0.4 — — 0.4 — — 0.8 Total $ 112.4 $ 7.4 $ 13.7 $ 0.9 $ 0.4 $ — $ 127.2 $ 262.0 Commercial construction: Pass $ 209.7 $ 141.4 $ 118.8 $ 27.6 $ — $ 0.5 $ — $ 498.0 Total $ 209.7 $ 141.4 $ 118.8 $ 27.6 $ — $ 0.5 $ — $ 498.0 Agricultural real estate: Pass $ 58.3 $ 36.9 $ 35.1 $ 22.6 $ 11.8 $ 28.1 $ 4.9 $ 197.7 Special mention 0.1 1.3 1.2 0.1 0.1 0.9 0.9 4.6 Substandard 4.0 0.4 1.0 0.6 1.3 4.3 — 11.6 Total $ 62.4 $ 38.6 $ 37.3 $ 23.3 $ 13.2 $ 33.3 $ 5.8 $ 213.9 December 31, 2021 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2021 2020 2019 2018 2017 Prior Revolving Loans Amortized Cost Basis Total Commercial and floor plans: Pass $ 394.2 $ 165.7 $ 94.5 $ 73.5 $ 47.1 $ 91.3 $ 224.7 $ 1,091.0 Special mention 0.8 11.4 0.8 0.8 3.0 2.3 7.0 26.1 Substandard 1.3 2.8 1.6 2.6 0.6 4.1 2.6 15.6 Total $ 396.3 $ 179.9 $ 96.9 $ 76.9 $ 50.7 $ 97.7 $ 234.3 $ 1,132.7 Commercial purpose secured by 1-4 family: Pass $ 94.9 $ 55.0 $ 27.8 $ 23.1 $ 15.3 $ 32.2 $ 14.4 $ 262.7 Special mention — 0.2 0.2 0.5 0.1 0.6 — 1.6 Substandard 1.3 1.2 0.6 0.6 0.2 1.3 0.1 5.3 Total $ 96.2 $ 56.4 $ 28.6 $ 24.2 $ 15.6 $ 34.1 $ 14.5 $ 269.6 Agricultural: Pass $ 35.1 $ 16.2 $ 9.0 $ 5.4 $ 2.1 $ 1.6 $ 108.9 $ 178.3 Special mention 0.2 4.1 0.1 0.4 0.6 0.3 7.0 12.7 Substandard 4.9 0.7 0.6 2.5 — 0.1 2.6 11.4 Total $ 40.2 $ 21.0 $ 9.7 $ 8.3 $ 2.7 $ 2.0 $ 118.5 $ 202.4 The Company evaluates the credit quality, loan performance, and the allowance for credit losses of its residential and consumer loan portfolios based primarily on the aging status of the loan and borrower payment activity. Accordingly, loans on nonaccrual status, loans past due 90 days or more and still accruing interest, and loans modified under TDRs are considered nonperforming for purposes of credit quality evaluation. The following tables present the recorded investment of our other loan portfolios based on the credit risk profile of loans that are performing and loans that are nonperforming as of the periods indicated: As of December 31, 2022 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2022 2021 2020 2019 2018 Prior Revolving Loans Amortized Cost Basis Total Residential 1-4 family: Performing $ 258.9 $ 490.3 $ 541.6 $ 98.0 $ 32.0 $ 213.8 $ — $ 1,634.6 Nonperforming — 0.2 0.1 0.5 0.3 3.7 — 4.8 Total $ 258.9 $ 490.5 $ 541.7 $ 98.5 $ 32.3 $ 217.5 $ — $ 1,639.4 Consumer home equity and HELOC: Performing $ 23.8 $ 8.0 $ 5.2 $ 5.5 $ 5.6 $ 15.2 $ 482.8 $ 546.1 Nonperforming 0.6 0.3 0.2 0.2 0.1 1.2 0.2 2.8 Total $ 24.4 $ 8.3 $ 5.4 $ 5.7 $ 5.7 $ 16.4 $ 483.0 $ 548.9 Consumer indirect: Performing $ 380.3 $ 176.4 $ 130.0 $ 59.7 $ 33.6 $ 46.3 $ — $ 826.3 Nonperforming 1.0 0.9 0.6 0.3 0.2 0.4 — 3.4 Total $ 381.3 $ 177.3 $ 130.6 $ 60.0 $ 33.8 $ 46.7 $ — $ 829.7 Consumer direct and advance line: Performing $ 52.6 $ 31.9 $ 18.2 $ 8.5 $ 6.5 $ 8.9 $ 25.8 $ 152.4 Nonperforming 0.1 0.1 0.1 — — 0.1 0.1 0.5 Total $ 52.7 $ 32.0 $ 18.3 $ 8.5 $ 6.5 $ 9.0 $ 25.9 $ 152.9 As of December 31, 2021 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2021 2020 2019 2018 2017 Prior Revolving Loans Amortized Cost Basis Total Residential 1-4 family: Performing $ 360.9 $ 477.0 $ 74.7 $ 27.5 $ 25.7 $ 176.5 $ — $ 1,142.3 Nonperforming — 0.3 — — 0.2 0.8 — 1.3 Total $ 360.9 $ 477.3 $ 74.7 $ 27.5 $ 25.9 $ 177.3 $ — $ 1,143.6 Consumer home equity and HELOC: Performing $ 11.1 $ 7.0 $ 3.7 $ 4.8 $ 3.6 $ 12.0 $ 350.7 $ 392.9 Nonperforming 0.3 — 0.3 — 0.6 0.5 — 1.7 Total $ 11.4 $ 7.0 $ 4.0 $ 4.8 $ 4.2 $ 12.5 $ 350.7 $ 394.6 Consumer indirect: Performing $ 272.6 $ 208.6 $ 108.3 $ 64.0 $ 37.0 $ 45.0 $ — $ 735.5 Nonperforming 0.5 0.5 0.4 0.2 0.1 0.4 — 2.1 Total $ 273.1 $ 209.1 $ 108.7 $ 64.2 $ 37.1 $ 45.4 $ — $ 737.6 Consumer direct and advance line: Performing $ 42.5 $ 27.9 $ 15.0 $ 13.3 $ 5.8 $ 7.6 $ 16.9 $ 129.0 Nonperforming 0.1 — — 0.1 — — — 0.2 Total $ 42.6 $ 27.9 $ 15.0 $ 13.4 $ 5.8 $ 7.6 $ 16.9 $ 129.2 While the Company considers the performance of the loan portfolio on the allowance for credit losses, for certain credit card loan classes, the Company also evaluates credit quality based on the aging status of the loan, which was previously presented, and by payment activity of the credit card holder. The following table presents the recorded investment in credit card loans based on payment activity for the periods indicated: As of December 31, 2022 Consumer Commercial Agricultural Total Credit Card: Performing $ 75.4 $ 100.0 $ 1.9 $ 177.3 Nonperforming 0.5 0.3 — 0.8 Total credit card $ 75.9 $ 100.3 $ 1.9 $ 178.1 As of December 31, 2021 Consumer Commercial Agricultural Total Credit Card: Performing $ 64.4 $ 73.1 $ 1.5 $ 139.0 Nonperforming 0.5 0.1 — 0.6 Total credit card $ 64.9 $ 73.2 $ 1.5 $ 139.6

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
Premises and Equipment (Tables)	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Premises and Equipment and Related Accumulated Depreciation	Premises and equipment and related accumulated depreciation are as follows: December 31, 2022 2021 Land $ 86.7 $ 52.0 Buildings and improvements 469.2 346.8 Furniture and equipment 111.0 97.0 Total premises and equipment 666.9 495.8 Less accumulated depreciation (222.2) (196.2) Premises and equipment, net $ 444.7 $ 299.6

Company-Owned Life Insurance (T

Company-Owned Life Insurance (Tables)	12 Months Ended
Company-Owned Life Insurance (Tables)	Dec. 31, 2022
Investments, All Other Investments [Abstract]
Schedule of Life Insurance Corporate or Bank Owned	Company-owned life insurance consists of the following: December 31, 2022 2021 Key executive, principal shareholder $ 3.2 $ 3.2 Key executive split dollar 7.1 7.1 Group life 487.6 291.2 Total $ 497.9 $ 301.5

Other Real Estate Owned (Tables

Other Real Estate Owned (Tables)	12 Months Ended
Other Real Estate Owned (Tables)	Dec. 31, 2022
Repossessed Assets [Abstract]
Other Real Estate Owned	Information with respect to the Company’s other real estate owned follows: Year Ended December 31, 2022 2021 2020 Balance at beginning of year $ 2.0 $ 2.5 $ 8.5 OREO acquired through acquisitions 15.8 — — Additions 0.4 0.9 3.3 Valuation adjustments (2.8) — (0.1) Dispositions (2.7) (1.4) (9.2) Balance at end of year $ 12.7 $ 2.0 $ 2.5

Mortgage Servicing Rights (Tabl

Mortgage Servicing Rights (Tables)	12 Months Ended
Mortgage Servicing Rights (Tables)	Dec. 31, 2022
Transfers and Servicing [Abstract]
Schedule of Servicing Assets at Amortized Value	Information with respect to the Company’s mortgage servicing rights follows: Year Ended December 31, 2022 2021 2020 Balance at beginning of year $ 31.6 $ 34.3 $ 30.6 Acquisition of mortgage servicing rights 1.3 — — Originations of mortgage servicing rights 2.5 3.7 11.7 Amortization expense (4.3) (6.4) (8.0) Balance at end of year 31.1 31.6 34.3 Less valuation reserve — (3.4) (10.3) Balance at end of year, net of valuation reserve $ 31.1 $ 28.2 $ 24.0 Principal balance of serviced loans underlying mortgage servicing rights $ 3,259.8 $ 3,203.7 $ 3,585.5 Mortgage servicing rights as a percentage of serviced loans 0.95 % 0.88 % 0.67 %

Deposits (Tables)

Deposits (Tables)	12 Months Ended
Deposits (Tables)	Dec. 31, 2022
Deposits [Abstract]
Schedule of Deposits, By Type	Deposits are summarized as follows: December 31, 2022 2021 Non-interest bearing demand $ 7,560.0 $ 5,568.3 Interest bearing: Demand 7,205.9 4,753.2 Savings 8,379.3 4,981.6 Time, $250 and over 438.0 186.7 Time, other 1,490.4 779.8 Total interest bearing 17,513.6 10,701.3 Total deposits $ 25,073.6 $ 16,269.6
Schedule of Maturities of Time Deposits	Maturities of time deposits at December 31, 2022 are as follows: Time, $250 Total Time Due within 3 months or less $ 47.8 $ 311.8 Due after 3 months and within 6 months 34.6 215.4 Due after 6 months and within 12 months 283.9 1,005.4 Due within 2024 55.0 282.8 Due within 2025 10.7 69.2 Due within 2026 4.8 27.8 Due within 2027 and thereafter 1.2 16.0 Total $ 438.0 $ 1,928.4

Long-Term Debt and Other Borr_2

Long-Term Debt and Other Borrowed Funds (Tables)	12 Months Ended
Long-Term Debt and Other Borrowed Funds (Tables)	Dec. 31, 2022
Debt Disclosure [Abstract]
Summary of Long-Term Debt	A summary of long-term debt follows: December 31, 2022 2021 Parent Company: Fixed to floating subordinated notes, 5.25% fixed rate effective May 2020 through May 2025 $ 98.9 $ 98.7 Subsidiaries: 8.00% finance lease obligation with term ending October 25, 2029 1.0 1.0 2.28% note payable maturing July 29, 2022, principal due at maturity, interest payable monthly — 5.0 1.00% note payable maturing December 31, 2041, interest only payable quarterly until December 31, 2025 and then principal and interest until maturity 5.1 5.1 Note payable maturing March 31, 2038, interest only payable at 1.30% monthly until March 31, 2025 and then principal and interest at 3.25% until maturity 2.0 2.0 1.30% note payable maturing June 1, 2034, interest only payable monthly until March 31, 2025 and then principal and interest until maturity 0.6 0.6 1.12% note payable maturing December 31, 2045, interest only payable annually until December 31, 2028 and then principal and interest until maturity 6.8 — 1.35% note payable maturing December 31, 2046 interest only payable annually until December 31, 2025 and then principal and interest until maturity 6.4 — Total long-term debt $ 120.8 $ 112.4
Schedule of Maturities of Long-term Debt	Maturities of long-term debt at December 31, 2022 were as follows: 2023 $ 0.1 2024 0.1 2025 0.1 2026 0.1 2027 0.2 Thereafter 120.2 Total $ 120.8

Regulatory Capital (Tables)

Regulatory Capital (Tables)	12 Months Ended
Regulatory Capital (Tables)	Dec. 31, 2022
Banking Regulation, Risk-Based Information [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	The Company’s actual capital amounts and ratios and selected minimum regulatory thresholds and prompt corrective action provisions as of December 31, 2022 and 2021 are presented in the following tables: Actual Minimum Required for Capital Adequacy Purposes For Capital Adequacy Purposes Plus Capital Conservation Buffer Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements (1) December 31, 2022 Amount Ratio Amount Ratio Amount Ratio Amount Ratio Total risk-based capital: Consolidated $ 2,875.8 12.48 % $ 1,843.2 8.00 % $ 2,419.2 10.50 % $ 2,304.0 10.00 % FIB 2,713.5 11.80 1,839.6 8.00 2,414.5 10.50 2,299.5 10.00 Tier 1 risk-based capital: Consolidated 2,408.8 10.45 1,382.4 6.00 1,958.4 8.50 1,843.2 8.00 FIB 2,504.1 10.89 1,379.7 6.00 1,954.6 8.50 1,839.6 8.00 Common equity tier 1 risk-based capital: Consolidated 2,408.8 10.45 1,036.8 4.50 1,612.8 7.00 1,497.6 6.50 FIB 2,504.1 10.89 1,034.8 4.50 1,609.7 7.00 1,494.7 6.50 Leverage capital ratio: Consolidated 2,408.8 7.75 1,242.9 4.00 1,242.9 4.00 1,553.6 5.00 FIB 2,504.1 8.07 1,241.1 4.00 1,241.1 4.00 1,551.4 5.00 December 31, 2021 Amount Ratio Amount Ratio Amount Ratio Amount Ratio Total risk-based capital: Consolidated $ 1,659.3 14.11 % $ 940.9 8.00 % $ 1,235.0 10.50 % $ 1,176.2 10.00 % FIB 1,472.5 12.56 938.0 8.00 1,231.1 10.50 1,172.5 10.00 Tier 1 risk-based capital: Consolidated 1,469.0 12.49 705.7 6.00 999.7 8.50 940.9 8.00 FIB 1,382.2 11.79 703.5 6.00 996.6 8.50 938.0 8.00 Common equity tier 1 risk-based capital: Consolidated 1,384.8 11.77 529.3 4.50 823.3 7.00 764.5 6.50 FIB 1,382.2 11.79 527.6 4.50 820.8 7.00 762.1 6.50 Leverage capital ratio: Consolidated 1,469.0 7.68 765.5 4.00 765.5 4.00 956.9 5.00 FIB 1,382.2 7.24 764.1 4.00 764.1 4.00 955.1 5.00 (1) The ratios for the well capitalized requirement are only applicable to FIB. However, the Company manages its capital position as if the requirement applies to the consolidated entity and has presented the ratios as if they also applied on a consolidated basis.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
Commitments and Contingencies (Tables)	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	The total future minimum rental commitments, exclusive of maintenance and operating costs, required under operating leases that have initial or remaining noncancelable lease terms in excess of one year at December 31, 2022, are as follows: Third Parties Related Entity Total For the year ending December 31: 2023 $ 10.1 $ 1.4 $ 11.5 2024 9.1 1.4 10.5 2025 7.7 1.4 9.1 2026 6.5 0.9 7.4 2027 4.7 0.1 4.8 Thereafter 10.6 — 10.6 Total $ 48.7 $ 5.2 $ 53.9

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Schedule of Income Tax Expense	Income tax expense consists of the following: Year ended December 31, 2022 2021 2020 Current: Federal $ 45.2 $ 39.4 $ 42.4 State 14.4 11.3 12.3 Total current 59.6 50.7 54.7 Deferred: Federal (3.7) 3.7 (5.7) State (1.0) 1.3 (0.9) Total deferred (4.7) 5.0 (6.6) Total income tax expense $ 54.9 $ 55.7 $ 48.1
Schedule of Effective Income Tax Rate Reconciliation	Total income tax provision differs from the amount of income tax determined by applying the statutory federal income tax rate of 21% for the periods presented to income before income taxes due to the following: Year ended December 31, 2022 2021 2020 Tax expense at the statutory tax rate $ 54.0 $ 52.0 $ 44.0 Increase (decrease) in tax resulting from: Tax-exempt income (8.4) (2.8) (2.1) State income tax, net of federal income tax benefit 10.6 9.9 9.0 Deficiency (benefit) of stock-based compensation plans 0.2 (0.5) (0.4) Nondeductible transaction costs 2.0 0.8 — Federal tax credits (4.3) (4.3) (2.3) Other, net 0.8 0.6 (0.1) Tax expense at effective tax rate $ 54.9 $ 55.7 $ 48.1
Schedule of Deferred Tax Assets and Liabilities	The tax effects of temporary differences between the financial statement carrying amounts and tax bases of assets and liabilities that give rise to significant portions of the net deferred tax asset (liability) relate to the following: December 31, 2022 2021 Deferred tax assets: Loans, principally due to allowance for credit losses $ 54.8 $ 30.7 Loan discount 32.5 1.6 Investment securities, unrealized losses 157.9 4.6 Derivatives, unrealized losses 0.5 — Deferred compensation 26.8 19.3 Non-performing loan interest 2.6 1.0 Other real estate owned write-downs and carrying costs 1.5 — Net operating loss carryforwards (1) 1.5 1.7 Lease liabilities 12.0 8.7 Other reserves 8.8 — Contract incentives 8.5 — Discount on acquired investment securities 13.4 — Other 2.4 3.5 Deferred tax assets $ 323.2 $ 71.1 December 31, 2022 2021 Deferred tax liabilities: Fixed assets, principally differences in bases and depreciation $ (17.3) $ (7.7) Deferred loan costs (3.3) (1.9) Derivatives, unrealized gains — (1.0) Investment in joint venture partnership, principally due to differences in depreciation of partnership assets (1.3) (0.9) Right of use assets (11.3) (8.3) Prepaid amounts (0.9) (0.7) Government agency stock dividends (1.2) (1.2) Goodwill and other intangibles (68.2) (51.2) Mortgage servicing rights (7.4) (6.8) Other (1.8) (0.7) Deferred tax liabilities (112.7) (80.4) Net deferred tax assets (liabilities) $ 210.5 $ (9.3) (1) As of December 31, 2022, we had remaining federal net operating loss carryforwards of $2.7 million from acquired companies, which is available to offset federal taxable income and state net operating loss carryforwards in amounts which vary by state. The federal net operating losses will expire beginning in 2030 and ending in 2036 and the state net operating losses will expire beginning in 2023 and ending in 2034. The use of these carryforwards is subject to annual limitations.

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
Stock-Based Compensation (Tables)	Dec. 31, 2022
Share-based Payment Arrangement [Abstract]
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity	The following table presents information regarding the Company’s restricted stock: As of December 31, 2022 Number of Weighted-Average Restricted stock, beginning of year 521,012 $ 39.73 Granted 458,176 38.67 Vested (131,199) 39.92 Forfeited (106,891) 38.61 Restricted stock, end of year 741,098 $ 38.94

Other Comprehensive Income (Tab

Other Comprehensive Income (Tables)	12 Months Ended
Other Comprehensive Income (Tables)	Dec. 31, 2022
Equity [Abstract]
Schedule of Comprehensive Income (Loss)	The gross amounts of each component of other comprehensive (loss) income and the related tax effects for the periods indicated are as follows: Year Ended December 31, 2022 Before Tax Amount Tax Expense (Benefit) Net of Tax Amount Investment securities available-for sale: Change in net unrealized loss during period $ (613.1) $ (152.4) $ (460.7) Reclassification adjustment for net gains included in net income 24.4 5.5 18.9 Reclassification adjustment for securities transferred from held-to-maturity to available-for-sale 0.2 0.1 0.1 Net change in unamortized gains on available-for-sale securities transferred into held-to-maturity (26.1) (6.6) (19.5) Change in net unrealized loss on derivatives (6.7) (1.8) (4.9) Total other comprehensive loss $ (621.3) $ (155.2) $ (466.1) Year Ended December 31, 2021 Before Tax Amount Tax Expense (Benefit) Net of Tax Amount Investment securities available-for sale: Change in net unrealized loss during period $ (113.7) $ (28.7) $ (85.0) Reclassification adjustment for net gains included in net income (1.1) (0.3) (0.8) Net change in unamortized gains on available-for-sale securities transferred into held-to-maturity 20.2 5.1 15.1 Change in net unrealized loss on derivatives 4.2 1.1 3.1 Total other comprehensive loss $ (90.4) $ (22.8) $ (67.6) Year Ended December 31, 2020 Before Tax Amount Tax Expense (Benefit) Net of Tax Amount Investment securities available-for sale: Change in net unrealized gains during period $ 61.8 $ 15.8 $ 46.0 Reclassification adjustment for net gains included in net income (0.3) (0.1) (0.2) Change in net unrealized loss on derivatives 0.2 — 0.2 Defined benefits post-retirement benefit plan: Change in net actuarial gains (0.5) (0.1) (0.4) Total other comprehensive income $ 61.2 $ 15.6 $ 45.6
Schedule of Accumulated Other Comprehensive Income (Loss)	The components of accumulated other comprehensive loss, net of income taxes, are as follows: Years ended December 31, 2022 2021 Net unrealized loss on investment securities available-for-sale $ (471.0) $ (29.0) Net unrealized (loss) gain on investment securities transferred to held-to-maturity (4.5) 15.0 Net unrealized (loss) gain on derivatives (1.6) 3.0 Net accumulated other comprehensive loss $ (477.1) $ (11.0)

Condensed Financial Informati_2

Condensed Financial Information (Parent Company Only) (Tables)	12 Months Ended
	Dec. 31, 2022
Condensed Financial Information Disclosure [Abstract]
Schedule of Condensed Financial Statements	Following is condensed financial information of First Interstate BancSystem, Inc. December 31, 2022 2021 Condensed balance sheets: Cash and cash equivalents $ 154.8 $ 181.1 Investment in bank subsidiary 2,985.8 1,948.9 Advances to subsidiaries, net 0.1 5.9 Other assets 240.7 63.2 Total assets $ 3,381.4 $ 2,199.1 Other liabilities $ 45.6 $ 26.8 Long-term debt 98.9 98.7 Subordinated debentures held by subsidiary trusts 163.1 87.0 Total liabilities 307.6 212.5 Stockholders’ equity 3,073.8 1,986.6 Total liabilities and stockholders’ equity $ 3,381.4 $ 2,199.1 Years Ended December 31, 2022 2021 2020 Condensed statements of income: Dividends from subsidiaries $ 360.0 $ 160.0 $ 130.0 Other interest income 0.4 — 0.1 Other income, primarily management fees from subsidiaries 51.7 41.3 28.7 Total income 412.1 201.3 158.8 Salaries and benefits 40.6 36.4 31.5 Interest expense 12.6 8.2 6.6 Acquisition related expenses 62.3 11.6 — Other operating expenses, net 25.0 17.6 15.6 Total expenses 140.5 73.8 53.7 Earnings before income tax benefit 271.6 127.5 105.1 Income tax benefit (18.9) (7.6) (6.1) Income before undistributed earnings of subsidiaries 290.5 135.1 111.2 Undistributed (loss) earnings of subsidiaries (88.3) 57.0 50.0 Net income $ 202.2 $ 192.1 $ 161.2 Years Ended December 31, 2022 2021 2020 Condensed statements of cash flows: Cash flows from operating activities: Net income $ 202.2 $ 192.1 $ 161.2 Adjustments to reconcile net income to cash provided by operating activities: Undistributed losses (earnings) of subsidiaries 88.3 (57.0) (50.0) Stock-based compensation expense 9.6 8.9 7.5 Other, net (151.2) (3.2) (13.6) Net cash provided by operating activities 148.9 140.8 105.1 Cash flows from investing activities: Acquisition of bank holding company, net of cash and cash equivalents received (0.8) — — Net cash used in investing activities $ (0.8) $ — $ — Years Ended December 31, 2022 2021 2020 Cash flows from financing activities: Net increase in advances from subsidiaries $ 206.5 $ 23.7 $ 16.7 Proceeds from issuance of long-term debt — — 98.6 Proceeds from issuance of common stock, net of stock issuance costs 0.1 0.4 1.1 Purchase and retirement of common stock (198.9) (5.4) (116.8) Dividends paid to common stockholders (182.1) (101.6) (128.6) Net cash used in financing activities (174.4) (82.9) (129.0) Net change in cash and cash equivalents (26.3) 57.9 (23.9) Cash and cash equivalents, beginning of year 181.1 123.2 147.1 Cash and cash equivalents, end of year $ 154.8 $ 181.1 $ 123.2

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
Fair Value Measurements (Tables)	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on a Recurring Basis	Financial assets and financial liabilities measured at fair value on a recurring basis are as follows: Fair Value Measurements at Reporting Date Using As of December 31, 2022 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investment debt securities available-for-sale: U.S. Treasury notes $ 642.7 $ — $ 642.7 $ — State, county, and municipal securities 263.7 — 263.7 — Obligations of U.S. government agencies 198.9 — 198.9 — U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 4,259.7 — 4,259.7 — Private mortgage-backed securities 228.0 — 228.0 — Collateralized loan obligations 1,111.6 — 1,111.6 — Corporate Securities 241.5 — 241.5 — Loans held for sale 79.9 — 79.9 — Derivative assets: Interest rate swap contracts 45.1 — 45.1 — Forward loan sales contracts 0.1 — 0.1 — Derivative liabilities: Interest rate collars 5.4 — 5.4 — Interest rate swap contracts 154.2 — 154.2 — Deferred compensation plan assets 18.7 — 18.7 — Deferred compensation plan liabilities 18.7 — 18.7 — Fair Value Measurements at Reporting Date Using As of December 31, 2021 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investment debt securities available-for-sale: U.S. Treasury notes $ 684.7 $ 684.7 $ — $ — State, county, and municipal securities 427.5 — 427.5 — Obligations of U.S. government agencies 346.9 — 346.9 — U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations 2,018.1 — 2,018.1 — Private mortgage-backed securities 173.4 — 173.4 — Collateralized loan obligations 899.4 — 899.4 — Corporate securities 270.5 — 270.5 — Loans held for sale 30.1 — 30.1 — Derivative assets: Interest rate swap contracts 26.3 — 26.3 — Interest rate lock commitments 1.8 — 1.8 — Derivative liabilities: Interest rate swap contracts 18.2 — 18.2 — Deferred compensation plan assets 21.4 — 21.4 — Deferred compensation plan liabilities 21.4 — 21.4 —
Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on a Non-Recurring Basis	The following table presents information about the Company’s assets and liabilities measured at fair value on a non-recurring basis: Fair Value Measurements at Reporting Date Using As of December 31, 2022 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Gains (Losses) Collateral-dependent loans $ 39.1 $ — $ — $ 39.1 $ — Other real estate owned 12.7 — — 12.7 — Long-lived assets to be disposed of by sale 5.5 — — 5.5 (0.2) Fair Value Measurements at Reporting Date Using As of December 31, 2021 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Gains (Losses) Collateral-dependent loans $ 11.7 $ — $ — $ 11.7 $ — Other real estate owned 2.0 — — 2.0 — Long-lived assets to be disposed of by sale 1.3 — — 1.3 —
Fair Value Inputs, Assets, Quantitative Information	The following table presents additional quantitative information about assets measured at fair value on a non-recurring basis and for which the Company has utilized Level 3 inputs to determine fair values: As of December 31, 2022 Fair Value Valuation Technique Unobservable Inputs Range (Weighted Average) Collateral-dependent loans $ 39.1 Appraisal Appraisal adjustment 0% - 45% (7%) Other real estate owned 12.7 Appraisal Appraisal adjustment 15 - 36 (22) Long-lived assets to be disposed of by sale 5.5 Appraisal Appraisal adjustment 0 - 6 (3) As of December 31, 2021 Collateral-dependent loans $ 11.7 Appraisal Appraisal adjustment 1% - 18% (7%)
Fair Value, by Balance Sheet Grouping	The estimated fair values of financial instruments that are reported in the Company’s consolidated balance sheets, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value, are as follows: ` Fair Value Measurements at Reporting Date Using As of December 31, 2022 Carrying Amount Estimated Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Financial assets: Cash and cash equivalents $ 870.5 $ 870.5 $ 870.5 $ — $ — Investment debt securities available-for-sale 6,946.1 6,946.1 — 6,946.1 — Investment debt securities held-to-maturity 3,451.8 3,052.2 — 3,052.2 — Accrued interest receivable 118.3 118.3 — 118.3 — Mortgage servicing rights, net 31.1 37.4 — 37.4 — Loans held for sale 79.9 79.9 — 79.9 — Net loans held for investment 17,879.1 17,552.1 — 17,513.0 39.1 Derivative assets 45.2 45.2 — 45.2 — Deferred compensation plan assets 18.7 18.7 — 18.7 — Total financial assets $ 29,440.7 $ 28,720.4 $ 870.5 $ 27,810.8 $ 39.1 Financial liabilities: Total deposits, excluding time deposits $ 23,145.2 $ 23,145.2 $ 23,145.2 $ — $ — Time deposits 1,928.4 1,876.1 — 1,876.1 — Securities sold under repurchase agreements 1,052.9 1,052.9 — 1,052.9 — Other borrowed funds 2,327.0 2,327.0 — 2,327.0 — Accrued interest payable 14.5 14.5 — 14.5 — Long-term debt 120.8 116.3 — 116.3 — Subordinated debentures held by subsidiary trusts 163.1 155.8 — 155.8 — Derivative liabilities 159.6 159.6 — 159.6 — Deferred compensation plan liabilities 18.7 18.7 — 18.7 — Total financial liabilities $ 28,930.2 $ 28,866.1 $ 23,145.2 $ 5,720.9 $ — Fair Value Measurements at Reporting Date Using As of December 31, 2021 Carrying Amount Estimated Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial assets: Cash and cash equivalents $ 2,344.8 $ 2,344.8 $ 2,344.8 $ — $ — Investment debt securities available-for-sale 4,820.5 4,820.5 684.7 4,135.8 — Investment debt securities held-to-maturity 1,687.6 1,667.5 — 1,667.5 — Accrued interest receivable 47.4 47.4 — 47.4 — Mortgage servicing rights, net 28.2 28.2 — 28.2 — Loans held for sale 30.1 30.1 — 30.1 — Net loans held for investment 9,209.4 9,254.3 — 9,242.6 11.7 Derivative assets 28.1 28.1 — 28.1 — Deferred compensation plan assets 21.4 21.4 — 21.4 — Total financial assets $ 18,217.5 $ 18,242.3 $ 3,029.5 $ 15,201.1 $ 11.7 Financial liabilities: Total deposits, excluding time deposits $ 15,303.1 $ 15,303.1 $ 15,303.1 $ — $ — Time deposits 966.5 963.1 — 963.1 — Securities sold under repurchase agreements 1,051.1 1,051.1 — 1,051.1 — Accrued interest payable 3.7 3.7 — 3.7 — Long-term debt 112.4 120.7 — 120.7 — Subordinated debentures held by subsidiary trusts 87.0 85.5 — 85.5 — Derivative liabilities 18.2 18.2 — 18.2 — Deferred compensation plan liabilities 21.4 21.4 — 21.4 — Total financial liabilities $ 17,563.4 $ 17,566.8 $ 15,303.1 $ 2,263.7 $ —

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2022 USD ($) segment subsidiary	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Property, Plant and Equipment
Deficiency (benefit) of stock-based compensation plans	$ 200,000	$ (500,000)	$ (400,000)
Impairment losses	$ 0	0	0
Number of significant subsidiaries \| subsidiary	1
Income tax examination, penalties	$ 0	0	0
Cash on deposit with Federal Reserve Bank	518,900,000	2,166,100,000
Federal Reserve Bank stock	93,600,000	42,800,000
Federal Home Loan Bank stock	103,800,000	10,600,000
Advertising expense	3,800,000	2,600,000	$ 2,800,000
Loans and Leases Receivable Disclosure [Line Items]
Accrued interest receivable	118,300,000	47,400,000
Accrued Investment Income Receivable	38,900,000	16,600,000
Hosting Arrangement, Service Contract, Implementation Cost, Expense, Amortization	$ 3,400,000	4,600,000
Number of operating segments \| segment	1
Total investment securities	$ 1,200,000	400,000
Buildings and improvements \| Minimum
Property, Plant and Equipment
Estimated useful lives	5 years
Buildings and improvements \| Maximum [Member]
Property, Plant and Equipment
Estimated useful lives	45 years
Furniture and equipment \| Minimum
Property, Plant and Equipment
Estimated useful lives	3 years
Furniture and equipment \| Maximum [Member]
Property, Plant and Equipment
Estimated useful lives	15 years
Loans
Loans and Leases Receivable Disclosure [Line Items]
Accrued interest receivable	$ 76,500,000	$ 30,200,000

Acquisitions - Narrative (Detai

Acquisitions - Narrative (Details) $ / shares in Units, $ in Millions		12 Months Ended
	Feb. 01, 2022 USD ($) office $ / shares shares	Dec. 31, 2022 USD ($) segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Net		$ 97	$ 41.3
Goodwill		$ 1,100.9	621.6	$ 621.6
Number of operating segments \| segment		1
Finite-lived intangible assets acquired		$ 72.9
Estimated useful lives of related deposits		12 years
Acquisition related expenses		$ 118.9	11.6	$ 0
Change in goodwill		(36.7)
Core Deposits Intangibles
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Net		75.9	41.3
Finite-lived intangible assets acquired		$ 50.1
Estimated useful lives of related deposits	10 years	10 years
Great Western Bank
Business Acquisition [Line Items]
Core deposit intangible assets	$ 50.1
Number of banking offices \| office	174
Total consideration paid	$ 1,723.3
Goodwill	479.3
Great Western Bank \| First Interstate Foundation
Business Acquisition [Line Items]
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Costs	21.5
Great Western Bank \| Scott Family
Business Acquisition [Line Items]
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Costs	$ 8.2
Great Western Bank \| Class A Common Stock
Business Acquisition [Line Items]
Common stock issued (in shares) \| shares	46,879,601
Business Acquisition, Share Price \| $ / shares	$ 36.76
Great Western Bank \| Customer Relationships
Business Acquisition [Line Items]
Estimated useful lives of related deposits	12 years
Acquisition Related Costs as Defined by ASC 805
Business Acquisition [Line Items]
Acquisition related expenses		$ 26.8	$ 9

Acquisitions - Schedule of Reco

Acquisitions - Schedule of Recognized Identifiable Assets Acquired and Liabilities Assumed (Details) $ / shares in Units, $ in Thousands		12 Months Ended
	Feb. 01, 2022 USD ($) office $ / shares shares	Dec. 31, 2022 USD ($) segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Business Acquisition [Line Items]
Goodwill		$ 1,100,900	$ 621,600	$ 621,600
Estimated useful lives of related deposits		12 years
Number of operating segments \| segment		1
Great Western Bank
Business Acquisition [Line Items]
Number of banking offices \| office	174
Cash and cash equivalents	$ 2,006,900
Business Combination, Recognized Identifiable Assets Acquirede and Liablilities Assumed, Current Assets, Securities Purchased Under Agreement to Resell	101,100
business combinatios, recognized identifiable assets acquired and liabilities assumed, loans held	217,000
Investment securities	2,699,000
Business Combinations, Recognized Identifiable Assets Acquired And Liabilities Assumed, Loans Held for Investment	7,705,000
Business Combinations, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans and Leases Receivable, Allowance	(59,500)
Premises and equipment	144,700
Business Combinations, Recognized Identifiable Assests Acquired and Liabilities Assumed Other Real Estate Owned	15,800
Company owned life insurance	186,600
Core deposit intangible assets	50,100
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	22,800
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Mortgage Servicing Rights	1,300
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets	60,200
Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Other Assets	200,800
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Accounts Payable And Accrued Expense	110,400
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Federal Home Loan Bank Advances	122,900
Total assets acquired	13,351,800
Deposits	11,688,000
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Other Liabilities	36,400
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Liabilities	76,100
Total liabilities assumed	12,107,800
Net assets acquired	1,244,000
Class A common stock	1,723,300
Total consideration paid	1,723,300
Goodwill	479,300
Buisness Combination, Recognizable Assets Acquired and Liabilities Assumed, Securities Sold Under Repurchase Agreement	74,000
Business Combination, Consideration Paid in Lieu of Fractional Shares	$ 13
Great Western Bank \| Class A Common Stock
Business Acquisition [Line Items]
Common stock issued (in shares) \| shares	46,879,601
Business Acquisition, Share Price \| $ / shares	$ 36.76
Core Deposits Intangibles
Business Acquisition [Line Items]
Estimated useful lives of related deposits	10 years	10 years

Acquisitions - Schedule of Acqu

Acquisitions - Schedule of Acquisition Related Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Business Combinations [Abstract]
Acquisition related expenses	$ 118.9	$ 11.6	$ 0

Acquisitions - Schedules of Loa

Acquisitions - Schedules of Loans Acquired (Details) $ in Millions	Feb. 01, 2022 USD ($)
Business Acquisition [Line Items]
Certain Loans Acquired in Transfer Accounted for as Available-for-Sale Debt Securities, Accrued Interest	$ (18.1)
Purchase Price (Initial Fair Value)	623.3
Great Western Bank
Business Acquisition [Line Items]
Contractually required principal and interest payments	979.2
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Other-than-Temporary Impairment Charges, Credit Loss	238.7
Contractual cash flows not expected to be collected (“non-accretable discount”)	29.9
Purchase Price (Initial Fair Value)	623.3
Interest component of cash flows expected to be collected (“accretable discount”)	(69.2)
Fair value of acquired credit-impaired loans	682.8
Contractually required principal and interest payments	7,107.9
Contractual cash flows not expected to be collected	9.2
Fair value at acquisition	7,022.2
Certain Loans Acquired in Transfer Accounted for as Available-for-sale Debt Securities, Acquired, at Acquisition, at Fair Value	$ 722.4

Acquisitions - Schedule of Unau

Acquisitions - Schedule of Unaudited Pro Forma Revenue and Income (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Feb. 01, 2022	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Estimated useful lives of related deposits		12 years
Business Acquisition, Pro Forma Earnings Per Share, Basic		$ 3.28	$ 2.24
Business Acquisition, Pro Forma Earnings Per Share, Diluted		$ 3.28	$ 2.24
Great Western Bank
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Revenue		$ 1,223.3	$ 1,200.9
Business Acquisition, Pro Forma Net Income (Loss)		$ 351.6	$ 243.3
Core Deposits Intangibles
Business Acquisition [Line Items]
Estimated useful lives of related deposits	10 years	10 years

Acquisitions - Schedule of Ac_2

Acquisitions - Schedule of Acquired Loans with Credit Impairment (Details) $ in Millions	Feb. 01, 2022 USD ($)
Business Acquisition [Line Items]
Purchase Price (Initial Fair Value)	$ 623.3
Allowance for loans losses	298.2
Great Western Bank
Business Combination and Asset Acquisition [Abstract]
Contractually required principal and interest payments	979.2
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Other-than-Temporary Impairment Charges, Credit Loss	(238.7)
Business Acquisition [Line Items]
Certain Loans Acquired in Transfer Accounted for as Available-for-sale Debt Securities, Acquired, at Acquisition, at Fair Value	722.4
Interest component of cash flows expected to be collected (“accretable discount”)	(69.2)
Contractual cash flows not expected to be collected (“non-accretable discount”)	(29.9)
Purchase Price (Initial Fair Value)	623.3
Allowance for loans losses	59.5
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, at Acquisition, at Fair Value	682.8
Contractually required principal and interest payments	7,107.9
Loans Acquired in Transfer, Accretable Yield	(76.5)
Contractual cash flows not expected to be collected	(9.2)
Loans Acquired in Transfer at Acquisition Fair Value	7,022.2
Loans Acquired in Transfer, Amortized cost basis	$ 7,705

Acquisitions - Schedule of Adju

Acquisitions - Schedule of Adjustments to Goodwill (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)
Business Acquisition [Line Items]
Change in goodwill	$ (36.7)
Accrued Expenses and Other Liabilities
Business Acquisition [Line Items]
Change in goodwill	3.3
Total Liability Adjustments
Business Acquisition [Line Items]
Change in goodwill	3.3
Mortgage loans originated for sale
Business Acquisition [Line Items]
Change in goodwill	35.1
Loans held for investment
Business Acquisition [Line Items]
Change in goodwill	(8.4)
Allowance for Credit Losses
Business Acquisition [Line Items]
Change in goodwill	24.8
Premises and Equipment
Business Acquisition [Line Items]
Change in goodwill	0.6
Core Deposit Intangibles
Business Acquisition [Line Items]
Change in goodwill	1
Deferred Tax Assets
Business Acquisition [Line Items]
Change in goodwill	(15.9)
Total Asset Adjustments
Business Acquisition [Line Items]
Change in goodwill	40
Other Assets
Business Acquisition [Line Items]
Change in goodwill	$ 2.8

Goodwill and Core Deposit Int_3

Goodwill and Core Deposit Intangibles - Goodwill Narrative (Details) - USD ($) $ in Millions					12 Months Ended
	Feb. 01, 2022	Jul. 01, 2020	Jul. 01, 2019	Jul. 01, 2018	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Line Items]
Impairment of goodwill		$ 0	$ 0	$ 0
Reductions due to sale of health savings accounts					$ 15.9	$ 9.9	$ 10.9
Estimated useful lives of related deposits					12 years
Core Deposits Intangibles
Goodwill [Line Items]
Estimated useful lives of related deposits	10 years				10 years

Goodwill and Core Deposit Int_4

Goodwill and Core Deposit Intangibles - Goodwill Carrying Value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Roll Forward]
Net carrying value at beginning of period	$ 621.6	$ 621.6
Net carrying value at end of period	1,100.9	621.6
Goodwill, Acquired During Period	479.3	0
Goodwill	$ 1,100.9	$ 621.6

Goodwill and Core Deposit Int_5

Goodwill and Core Deposit Intangibles - Schedule of Finite-Lived Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Finite-lived Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Gross		$ 106	$ 106
Finite-lived intangible assets acquired	$ 72.9
Finite-Lived Intangible Assets, Period Increase (Decrease)	(1.4)
Finite-Lived Intangible Assets, Accumulated Amortization	(80.5)	(64.7)
Finite-Lived Intangible Assets, Net	97	41.3
Core Deposits Intangibles
Finite-lived Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Gross		106	106
Finite-lived intangible assets acquired	50.1
Finite-Lived Intangible Assets, Period Increase (Decrease)	(1.4)
Finite-Lived Intangible Assets, Accumulated Amortization	(78.8)	(64.7)
Finite-Lived Intangible Assets, Net	75.9	41.3
OCRI
Finite-lived Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Gross		0	$ 0
Finite-lived intangible assets acquired	22.8
Finite-Lived Intangible Assets, Period Increase (Decrease)	0
Finite-Lived Intangible Assets, Accumulated Amortization	(1.7)	0
Finite-Lived Intangible Assets, Net	$ 21.1	$ 0

Goodwill and Core Deposit Int_6

Goodwill and Core Deposit Intangibles - Schedule of Future Estimated CDI Amortization Expense (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
2023	$ 15.6
2024	14.6
2025	13.7
2026	12.8
2027	10.1
Thereafter	30.2
Finite-Lived Intangible Assets, Net	97	$ 41.3
Core Deposits Intangibles
Finite-Lived Intangible Assets [Line Items]
2023	13.7
2024	12.7
2025	11.8
2026	10.9
2027	8.2
Thereafter	18.6
Finite-Lived Intangible Assets, Net	75.9	41.3
OCRI
Finite-Lived Intangible Assets [Line Items]
2023	1.9
2024	1.9
2025	1.9
2026	1.9
2027	1.9
Thereafter	11.6
Finite-Lived Intangible Assets, Net	$ 21.1	$ 0

Investment Securities - Narrati

Investment Securities - Narrative (Details) - USD ($)		12 Months Ended
Investment Securities - Narrative (Details) - USD ($)	Feb. 01, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Transfer, Amount	$ 10,700,000
Debt Securities, Held-To-Maturity, After Allowance for Credit Loss, Transfer, Amount	10,900,000
Debt Securities, Available-for-Sale, Amortized Cost, after Allowance for Credit Loss, Transfer, Amount	485,900,000
Debt Securities, Available-for-Sale, after Allowance for Credit Loss, Transfer, Amount	463,600,000
Debt Securities, Held-to-maturity, Transfer to Trading, Unrealized Gain (Loss)	$ 0
Debt Securities, Available-for-sale, Allowance for Credit Loss		$ 0	$ 0
Debt Securities, Available-for-sale, Realized Loss		(46,800,000)	(2,100,000)	$ 0
Debt Securities, Available-for-sale, Realized Gain		300,000	$ 3,200,000	$ 0
Gain (Loss) on Fair Value Hedges Recognized in Earnings		(46,300,000)
Debt Securities, Held-to-maturity, Nonaccrual		0
Treasury Security
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Realized Loss		22,100,000
Collateral
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities		0
Treasury Security
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Realized Loss		$ 24,200,000

Investment Securities - Amortiz

Investment Securities - Amortized Cost and Approximate Fair Values of Investment Securities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Available for Sale and Held-to-Maturity Securities
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost	$ 48.8
Available-for-Sale:
Amortized Cost	7,573.5	$ 4,859.3
Gross Unrealized Gains	2.3	20.6
Gross Unrealized Losses	(629.7)	(59.4)
Estimated Fair Value	6,946.1	4,820.5
Held-to-Maturity:
Amortized Cost	3,453.7	1,687.6
Allowance for Credit Losses	0.4	15.6
Gross Unrealized Losses	(400)	(35.7)
Held-to-maturity investment securities, estimated fair value	3,052.2	1,667.5
Debt Securities, Held-to-Maturity, Transfer, Unamortized Gain	14.2	20.1
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value	48.1
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	2.5
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value	2.5
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost	1,478.9
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value	1,419.8
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	607.6
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value	581.6
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Amortized Cost	1,750
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value	1,564.3
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	732.7
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value	639.5
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost	4,295.8
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	3,913.9
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after 10 Years, Amortized Cost	2,110.9
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	1,828.6
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(1.9)	0	$ 0	$ 0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	3,451.8	1,687.6
Debt and Equity Securities, Unrealized Gain (Loss)	(20.2)
US Treasury notes
Available-for-Sale:
Amortized Cost	675.1	697.6
Gross Unrealized Gains	2.1	0
Gross Unrealized Losses	(34.5)	(12.9)
Estimated Fair Value	642.7	684.7
Held-to-Maturity:
Amortized Cost	396.6
Allowance for Credit Losses	0
Gross Unrealized Losses	(10.2)
Held-to-maturity investment securities, estimated fair value	386.4
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	396.6
State, county and municipal securities
Available-for-Sale:
Amortized Cost	314.3	434.7
Gross Unrealized Gains	0	2.1
Gross Unrealized Losses	(50.6)	(9.3)
Estimated Fair Value	263.7	427.5
Held-to-Maturity:
Amortized Cost	181.2	67.6
Allowance for Credit Losses	0.2	2
Gross Unrealized Losses	(31.6)	(0.4)
Held-to-maturity investment securities, estimated fair value	149.7	69.2
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(0.1)	0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	181.1	67.6
US Government Agencies Debt Securities [Member]
Available-for-Sale:
Amortized Cost	216.2	356
Gross Unrealized Gains	0	0.1
Gross Unrealized Losses	(17.3)	(9.2)
Estimated Fair Value	198.9	346.9
Held-to-Maturity:
Amortized Cost	351.7
Allowance for Credit Losses	0
Gross Unrealized Losses	(49.6)
Held-to-maturity investment securities, estimated fair value	302.1
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	351.7
Corporate Debt Securities [Member]
Available-for-Sale:
Amortized Cost	272.3	271.1
Gross Unrealized Gains	0	3
Gross Unrealized Losses	(30.8)	(3.6)
Estimated Fair Value	241.5	270.5
Held-to-Maturity:
Amortized Cost	80.1	11
Allowance for Credit Losses	0	0.4
Gross Unrealized Losses	(7)	0
Held-to-maturity investment securities, estimated fair value	71.3	11.4
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(1.8)	0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	78.3	11
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-Sale:
Amortized Cost	4,685.5	2,027.3
Gross Unrealized Gains	0.2	14.1
Gross Unrealized Losses	(426)	(23.3)
Estimated Fair Value	4,259.7	2,018.1
Held-to-Maturity:
Amortized Cost	2,444.1	1,609
Allowance for Credit Losses	0.2	13.2
Gross Unrealized Losses	(301.6)	(35.3)
Held-to-maturity investment securities, estimated fair value	2,142.7	1,586.9
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0	0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	2,444.1	1,609
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Available-for-Sale:
Amortized Cost	264.9	174.4
Gross Unrealized Gains	0	0.1
Gross Unrealized Losses	(36.9)	(1.1)
Estimated Fair Value	228	173.4
Collateralized Loan Obligations
Available-for-Sale:
Amortized Cost	1,145.2	898.2
Gross Unrealized Gains	0	1.2
Gross Unrealized Losses	(33.6)	0
Estimated Fair Value	1,111.6	$ 899.4
Callable Within One Year [Member]
Schedule of Available for Sale and Held-to-Maturity Securities
Investment Securities, Primarily Classified As Available-For-Sale, Debt Maturities, Rolling Year Two Through Five, Amortized Cost Basis	1,443.3
Investment Securities, Primarily Classified As Available-For-Sale, Debt Maturities, Rolling Year Two Through Five, Fair Value	1,356.5
Held-to-Maturity:
Investment Securities, Callable Structured, Amortized Cost Basis	$ 0

Investment Securities - Realize

Investment Securities - Realized Gains (Losses) on Investments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Available-for-sale Securities
Debt Securities, Available-for-sale, Amortized Cost	$ 7,573.5	$ 4,859.3
Debt Securities, Available-for-sale, Realized Gain	0.3	3.2	$ 0
Debt Securities, Available-for-sale, Realized Loss	(46.8)	(2.1)	$ 0
US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities
Debt Securities, Available-for-sale, Amortized Cost	216.2	356
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities
Debt Securities, Available-for-sale, Amortized Cost	4,685.5	2,027.3
State, county and municipal securities
Schedule of Available-for-sale Securities
Debt Securities, Available-for-sale, Amortized Cost	314.3	434.7
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Schedule of Available-for-sale Securities
Debt Securities, Available-for-sale, Amortized Cost	264.9	174.4
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities
Debt Securities, Available-for-sale, Amortized Cost	$ 272.3	$ 271.1

Investment Securities - Gross U

Investment Securities - Gross Unrealized Losses and Fair Values of Investment Securities (Details) $ in Millions	Dec. 31, 2022 USD ($) Investments	Dec. 31, 2021 USD ($) Investments
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	$ 3,453.7	$ 1,687.6
Available-for-Sale and Held-to-Maturity:
Investment securities in an unrealized loss position (number of securities) \| Investments	1,222	285
Less than 12 Months	$ 1,923.9	$ 1,067.7
Less than 12 Months	(187.2)	(35.7)
12 Months or More	1,075.2	0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(212.8)	0
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	2,999.1	1,067.7
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss	(400)	(35.7)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	5,071.9	2,760.3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,545.6	68.7
Debt Securities, Available-for-sale, Unrealized Loss Position	6,617.5	2,829
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(629.7)	(59.4)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(346.6)	(58.3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(283.1)	(1.1)
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	2,444.1	1,609
Available-for-Sale and Held-to-Maturity:
Less than 12 Months	1,349.4	1,038.7
Less than 12 Months	(156.1)	(35.3)
12 Months or More	762.5	0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(145.5)	0
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	2,111.9	1,038.7
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss	(301.6)	(35.3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	3,299.7	1,262.8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	948.4	26.4
Debt Securities, Available-for-sale, Unrealized Loss Position	4,248.1	1,289.2
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(426)	(23.3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(262.3)	(23)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(163.7)	(0.3)
US Government Agencies Debt Securities [Member]
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	351.7
Available-for-Sale and Held-to-Maturity:
Less than 12 Months	86.1
Less than 12 Months	(9.9)
12 Months or More	216
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(39.7)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	302.1
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss	(49.6)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	152.2	297
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	46.1	16.4
Debt Securities, Available-for-sale, Unrealized Loss Position	198.3	313.4
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(17.3)	(9.2)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(10.1)	(8.9)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(7.2)	(0.3)
Corporate Debt Securities [Member]
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	80.1	11
Available-for-Sale and Held-to-Maturity:
Less than 12 Months	68.2
Less than 12 Months	(7)
12 Months or More	0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	68.2
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss	(7)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	130.6	109.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	110.8	20.9
Debt Securities, Available-for-sale, Unrealized Loss Position	241.4	130.8
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(30.8)	(3.6)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(8.3)	(3.3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(22.5)	(0.3)
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Available-for-Sale and Held-to-Maturity:
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	133.1	127.2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	94.9	0
Debt Securities, Available-for-sale, Unrealized Loss Position	228	127.2
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(36.9)	(1.1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(19.1)	(1.1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(17.8)	0
US Treasury notes
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	396.6
Available-for-Sale and Held-to-Maturity:
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	168.8	684.7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	170.4	0
Debt Securities, Available-for-sale, Unrealized Loss Position	339.2	684.7
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(34.5)	(12.9)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(4.7)	(12.9)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(29.8)	0
State, county and municipal securities
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	181.2	67.6
Available-for-Sale and Held-to-Maturity:
Less than 12 Months	33.8	29
Less than 12 Months	(4)	(0.4)
12 Months or More	96.7	0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(27.6)	0
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	130.5	29
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss	(31.6)	(0.4)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	104.9	278.7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	146.1	5
Debt Securities, Available-for-sale, Unrealized Loss Position	251	283.7
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(50.6)	(9.3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(9)	(9.1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(41.6)	$ (0.2)
Collateralized Loan Obligations
Available-for-Sale and Held-to-Maturity:
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,082.6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	28.9
Debt Securities, Available-for-sale, Unrealized Loss Position	1,111.5
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(33.6)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(33.1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(0.5)
US Treasury Notes Securities
Available-for-Sale and Held-to-Maturity:
Less than 12 Months	386.4
Less than 12 Months	(10.2)
12 Months or More	0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	386.4
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss	$ (10.2)

Investment Securities - Maturit

Investment Securities - Maturities of Investment Securities (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost	$ 48.8
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost	1,478.9
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Amortized Cost	1,750
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost	4,295.8
Amortized Cost	7,573.5	$ 4,859.3
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value	48.1
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value	1,419.8
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value	1,564.3
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	3,913.9
Estimated Fair Value	6,946.1	4,820.5
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	2.5
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	607.6
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	732.7
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after 10 Years, Amortized Cost	2,110.9
Amortized Cost	3,453.7	1,687.6
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value	2.5
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value	581.6
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value	639.5
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	1,828.6
Estimated Fair Value	3,052.2	1,667.5
Available-for-sale Securities and Held-to-maturity Securities
Securities sold under agreements to repurchase	4,998.9	2,617.8
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	$ 4,432	$ 2,610.8

Investment Securities - Held-to

Investment Securities - Held-to-Maturity Allowance for Credit Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss	$ 1.9	$ 0	$ 0	$ 0
Debt Securities, Held-to-maturity, Credit Loss Expense (Reversal)	$ 1.9	$ 0	$ 0

Investment Securities - Credit

Investment Securities - Credit Quality Indicators (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	$ 3,453.7	$ 1,687.6
AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	3,260.7	1,626.2
AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	92.8	31.6
A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	11.5	18.7
BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	65.1	7
BB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	10
Not Rated
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	13.6	4.1
US Treasury Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	396.6
US Treasury Securities [Member] \| AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	396.6
US Treasury Securities [Member] \| AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
US Treasury Securities [Member] \| A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
US Treasury Securities [Member] \| BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
US Treasury Securities [Member] \| BB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
US Treasury Securities [Member] \| Not Rated
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
State, county and municipal securities
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	181.2	67.6
State, county and municipal securities \| AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	68.3	17.2
State, county and municipal securities \| AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	92.8	31.6
State, county and municipal securities \| A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	11.5	14.7
State, county and municipal securities \| BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
State, county and municipal securities \| BB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
State, county and municipal securities \| Not Rated
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	8.6	4.1
US Government Agencies Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	351.7
US Government Agencies Debt Securities [Member] \| AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	351.7
US Government Agencies Debt Securities [Member] \| AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
US Government Agencies Debt Securities [Member] \| A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
US Government Agencies Debt Securities [Member] \| BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
US Government Agencies Debt Securities [Member] \| BB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
US Government Agencies Debt Securities [Member] \| Not Rated
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	2,444.1	1,609
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	2,233.6	1,439.1
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	210.5	169.9
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| AAA Rating \| FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	2,233.6	1,439.1
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| AAA Rating \| GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	210.5	169.9
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| AA Rating \| FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| AA Rating \| GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| A Rating \| FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| A Rating \| GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| BBB Rating \| FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| BBB Rating \| GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| BB Rating \| FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| BB Rating \| GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Not Rated \| FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Not Rated \| GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Corporate Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	80.1	11
Corporate Debt Securities [Member] \| AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Corporate Debt Securities [Member] \| AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Corporate Debt Securities [Member] \| A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	4
Corporate Debt Securities [Member] \| BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	65.1	7
Corporate Debt Securities [Member] \| BB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	10
Corporate Debt Securities [Member] \| Not Rated
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	$ 5	$ 0

Loans Held for Sale - Narrative

Loans Held for Sale - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Available-for-sale Securities
Loans Held for Sale (Table)	$ 79.9	$ 30.1
Amortization of unrealized gains and losses on transfers of securities	12.4	0	$ 0
Transfer of Loans Held-for-sale to Portfolio Loans	(19.8)	0	$ 0
Non-accrual Loans	39.8
Commercial Portfolio Segment [Member]
Schedule of Available-for-sale Securities
Non-accrual Loans	10.2	5
Commercial Real Estate Construction [Member]
Schedule of Available-for-sale Securities
Amortization of unrealized gains and losses on transfers of securities	12.4
Non-accrual Loans	0	0
Agricultural Financing Receivable [Member]
Schedule of Available-for-sale Securities
Amortization of unrealized gains and losses on transfers of securities	0
Non-accrual Loans	8.7	1.6
Commercial Loan
Schedule of Available-for-sale Securities
Amortization of unrealized gains and losses on transfers of securities	0
Agricultural Financing Receivable [Member]
Schedule of Available-for-sale Securities
Loans Held for Sale (Table)	62.5	0
Transfer of Loans Held-for-sale to Portfolio Loans	(19.8)
Proceeds from Sale of Loans Held-for-sale	0
Non-accrual Loans	29.3
Commercial Real Estate Construction [Member]
Schedule of Available-for-sale Securities
Loans Held for Sale (Table)	10.5	0
Amortization of unrealized gains and losses on transfers of securities	0
Increase (Decrease) in Fair Value Adjustments on Other Assets (Liabilities) Carried at Fair Value under Fair Value Option	(1.9)
Transfer of Loans Held-for-sale to Portfolio Loans	0
Proceeds from Collection of Loans Held-for-sale	0
Proceeds from Sale of Loans Held-for-sale	0
Non-accrual Loans	10.5
Residential Real Estate
Schedule of Available-for-sale Securities
Loans Held for Sale (Table)	6.9	30.1
Commercial Loan
Schedule of Available-for-sale Securities
Loans Held for Sale (Table)	0	$ 0
Amortization of unrealized gains and losses on transfers of securities	24
Increase (Decrease) in Fair Value Adjustments on Other Assets (Liabilities) Carried at Fair Value under Fair Value Option	0
Transfer of Loans Held-for-sale to Portfolio Loans	0
Proceeds from Collection of Loans Held-for-sale	(0.6)
Proceeds from Sale of Loans Held-for-sale	$ (23.4)

Loans Held for Investment - Sch

Loans Held for Investment - Schedule of Loans by Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2022	Dec. 31, 2021
Loans and Leases Receivable
Loans and Leases Receivable, Deferred Income		$ (15.6)	$ (12.3)
Loans and Leases Receivable, Net of Deferred Income		18,099.2	9,331.7
Accounts Receivable, Allowance for Credit Loss	$ (144.3)	(220.1)	(122.3)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	73
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	30
Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(54.8)	(74.6)	(43.9)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	19.5
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	15.3
Loans and Leases Receivable, Collateral for Secured Borrowings		8,528.6	3,971.5
Residential Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(1.6)	(3.6)	(2.4)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	1.5
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	0.9
Loans and Leases Receivable, Collateral for Secured Borrowings		516.2	262
Commercial Real Estate Construction [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(7.3)	(31.2)	(6)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	2.7
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	1.3
Loans and Leases Receivable, Collateral for Secured Borrowings		1,042	498
Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable
Loans and Leases Receivable, Collateral for Secured Borrowings		1,944.4	1,007.8
Residential Mortgage [Member]
Loans and Leases Receivable
Loans and Leases Receivable, Collateral for Secured Borrowings		2,188.3	1,538.2
Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(2.7)	(5.9)	(1.9)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	0.5
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	1.8
Loans and Leases Receivable, Collateral for Secured Borrowings		794.9	213.9
Real Estate Financing Receivable [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(80.5)	(138.7)	(69.3)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	28.9
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	28.5
Loans and Leases Receivable, Collateral for Secured Borrowings		13,456.2	6,731.4
Indirect consumer
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(16.7)	(15.3)	(14.3)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	4.5
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	8.8
Loans and Leases Receivable, Collateral for Secured Borrowings		829.7	737.6
Other consumer
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(4.6)	(5.2)	(4.6)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	2.9
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	3
Loans and Leases Receivable, Collateral for Secured Borrowings		152.9	129.2
Credit card consumer
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(2.6)	(2.8)	(2.2)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	2.5
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	0.3
Loans and Leases Receivable, Collateral for Secured Borrowings		75.9	64.9
Total consumer loans
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(23.9)	(23.3)	(21.1)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	9.9
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	12.1
Loans and Leases Receivable, Collateral for Secured Borrowings		1,058.5	931.7
Commercial Portfolio Segment [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(39.2)	(54.9)	(31.6)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	32.6
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	10
Loans and Leases Receivable, Collateral for Secured Borrowings		2,882.6	1,475.5
Agricultural Financing Receivable [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(0.7)	(3.2)	(0.3)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	1.6
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	0.6
Loans and Leases Receivable, Collateral for Secured Borrowings		708.3	203.9
Other, including overdrafts
Loans and Leases Receivable
Loans and Leases Receivable, Collateral for Secured Borrowings		9.2	1.5
Loans held for investment
Loans and Leases Receivable
Loans and Leases Receivable, Collateral for Secured Borrowings		18,114.8	9,344
Non Owner Occupied Loans
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(25.5)	(27.2)	(17.3)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	8.8
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	4.9
Commercial Real Estate Owner Occupied
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(18.3)	(19.5)	(13.3)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	10
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	3.5
Commercial Real Estate Multifamily
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(11)	(27.9)	(13.3)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	0.7
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	6.9
Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(1.3)	(1.3)	(0.5)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	1.9
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	0.1
Loans and Leases Receivable, Collateral for Secured Borrowings		386.2	247.8
Construction Loans
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(10.2)	(36.1)	(8.9)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	6.1
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	0.3
Residential Real Estate 1-4 Family
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(11.4)	(20.5)	(13.4)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	1.8
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(10.6)
Home Equity Loan
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(1.4)		(1.2)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	1
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(0.5)
Residential Real Estate
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(12.8)	(22.1)	(14.6)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	2.8
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(11.1)
Commercial and Floor Plans
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(34.2)	(49)	(27.1)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	25.5
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	5.1
Commercial Purpose Secured by 1-4 Family
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(4.7)	(5.7)	(4.4)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	5.9
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	3.8
Commercial Borrower
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(0.3)	$ (0.2)	$ (0.1)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	1.2
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	$ 1.1

Loans Held for Investment - S_2

Loans Held for Investment - Schedule of Allowance for Credit Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	$ 59.5
Provision charged (credited) to operating expense	82.7	$ (14.6)	$ 56.9
Less loans charged-off	(45)	(16.6)	(20.9)
Recoveries Collected	14.9	9.3	6.7
Accounts Receivable, Allowance for Credit Loss	220.1	122.3	144.3	$ 73
Off-Balance Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal)	68.4	(14.7)	55.5
Great Western Bank
Financing Receivable, Allowance for Credit Losses
Off-Balance Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal)	68.3
Non Owner Occupied Loans
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	17.2
Provision charged (credited) to operating expense	(4.2)	(8.3)	11.7
Less loans charged-off	(3.5)	0	0
Recoveries Collected	0.4	0.1	0.1
Accounts Receivable, Allowance for Credit Loss	27.2	17.3	25.5	8.8
Commercial Real Estate Owner Occupied
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	9.5
Provision charged (credited) to operating expense	(2.7)	(2.7)	5
Less loans charged-off	(2.5)	(2.3)	(0.4)
Recoveries Collected	1.9	0	0.2
Accounts Receivable, Allowance for Credit Loss	19.5	13.3	18.3	10
Commercial Real Estate Multifamily
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	10.9
Provision charged (credited) to operating expense	8.7	2.3	3.4
Less loans charged-off	(5.7)	0	0
Recoveries Collected	0.7	0	0
Accounts Receivable, Allowance for Credit Loss	27.9	13.3	11	0.7
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	37.6
Provision charged (credited) to operating expense	1.8	(8.7)	20.1
Less loans charged-off	(11.7)	(2.3)	(0.4)
Recoveries Collected	3	0.1	0.3
Accounts Receivable, Allowance for Credit Loss	74.6	43.9	54.8	19.5
Land Acquisition And Development Construction Financing Receivable [Member]
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	3.4
Provision charged (credited) to operating expense	(0.4)	(0.1)	(0.4)
Less loans charged-off	(2.6)	(1.2)	(0.5)
Recoveries Collected	0.4	0.5	0.4
Accounts Receivable, Allowance for Credit Loss	1.3	0.5	1.3	1.9
Residential Real Estate Construction Financing Receivable [Member]
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	0
Provision charged (credited) to operating expense	1.1	0.9	1
Less loans charged-off	0	(0.1)	0
Recoveries Collected	0.1	0	0
Accounts Receivable, Allowance for Credit Loss	3.6	2.4	1.6	1.5
Commercial Real Estate Construction [Member]
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	0.2
Provision charged (credited) to operating expense	31.6	(1.3)	3.3
Less loans charged-off	(6.6)	(0.1)	0
Recoveries Collected	0	0.1	0
Accounts Receivable, Allowance for Credit Loss	31.2	6	7.3	2.7
Construction Loans
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	3.6
Provision charged (credited) to operating expense	32.3	(0.5)	3.9
Less loans charged-off	(9.2)	(1.4)	(0.5)
Recoveries Collected	0.5	0.6	0.4
Accounts Receivable, Allowance for Credit Loss	36.1	8.9	10.2	6.1
Residential Real Estate 1-4 Family
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	0.1
Provision charged (credited) to operating expense	6.9	2	(1.1)
Less loans charged-off	(0.2)	0	0
Recoveries Collected	0.3	0	0.1
Accounts Receivable, Allowance for Credit Loss	20.5	13.4	11.4	1.8
Home equity line of credit
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	0
Provision charged (credited) to operating expense	0
Less loans charged-off	(0.1)
Recoveries Collected	0.5
Accounts Receivable, Allowance for Credit Loss	1.6	1.2
Residential Real Estate
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	0.1
Provision charged (credited) to operating expense	6.9	1.6	(1.5)
Less loans charged-off	(0.3)	(0.1)	0
Recoveries Collected	0.8	0.3	0.4
Accounts Receivable, Allowance for Credit Loss	22.1	14.6	12.8	2.8
Agricultural Real Estate Financing Receivable [Member]
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	2.3
Provision charged (credited) to operating expense	1.5	(0.1)	0.4
Less loans charged-off	(0.2)	(0.7)	0
Recoveries Collected	0.4	0	0
Accounts Receivable, Allowance for Credit Loss	5.9	1.9	2.7	0.5
Real Estate Financing Receivable [Member]
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	43.6
Provision charged (credited) to operating expense	42.5	(7.7)	22.9
Less loans charged-off	(21.4)	(4.5)	(0.9)
Recoveries Collected	4.7	1	1.1
Accounts Receivable, Allowance for Credit Loss	138.7	69.3	80.5	28.9
Indirect consumer
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	0
Provision charged (credited) to operating expense	2.7	(1.4)	5.4
Less loans charged-off	(4)	(3.5)	(4.1)
Recoveries Collected	2.3	2.5	2.1
Accounts Receivable, Allowance for Credit Loss	15.3	14.3	16.7	4.5
Other consumer
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	0
Provision charged (credited) to operating expense	2.2	1.7	1.6
Less loans charged-off	(3.7)	(2.9)	(3.9)
Recoveries Collected	2.1	1.2	1
Accounts Receivable, Allowance for Credit Loss	5.2	4.6	4.6	2.9
Credit card consumer
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	0
Provision charged (credited) to operating expense	2.4	0.6	1.8
Less loans charged-off	(2.4)	(1.8)	(2.8)
Recoveries Collected	0.6	0.8	0.8
Accounts Receivable, Allowance for Credit Loss	2.8	2.2	2.6	2.5
Total consumer loans
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	0
Provision charged (credited) to operating expense	7.3	0.9	8.8
Less loans charged-off	(10.1)	(8.2)	(10.8)
Recoveries Collected	5	4.5	3.9
Accounts Receivable, Allowance for Credit Loss	23.3	21.1	23.9	9.9
Commercial and Floor Plans
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	11.2
Provision charged (credited) to operating expense	15.1	(7.3)	20.4
Less loans charged-off	(6.6)	(3)	(8)
Recoveries Collected	2.2	3.2	1.4
Accounts Receivable, Allowance for Credit Loss	49	27.1	34.2	25.5
Commercial Purpose Secured by 1-4 Family
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	0.2
Provision charged (credited) to operating expense	1.2	(0.5)	2.5
Less loans charged-off	(0.2)	(0.3)	(0.1)
Recoveries Collected	0.1	0.5	0.2
Accounts Receivable, Allowance for Credit Loss	5.7	4.4	4.7	5.9
Commercial Borrower
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	0
Provision charged (credited) to operating expense	1.4	0.1	1.1
Less loans charged-off	(1.3)	(0.4)	(1)
Recoveries Collected	0	0.1	0.1
Accounts Receivable, Allowance for Credit Loss	0.2	0.1	0.3	1.2
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	11.4
Provision charged (credited) to operating expense	17.7	(7.7)	24
Less loans charged-off	(8.1)	(3.7)	(9.1)
Recoveries Collected	2.3	3.8	1.7
Accounts Receivable, Allowance for Credit Loss	54.9	31.6	39.2	32.6
Agricultural Financing Receivable [Member]
Financing Receivable, Allowance for Credit Losses
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date	4.5
Provision charged (credited) to operating expense	0.9	(0.2)	(0.2)
Less loans charged-off	(5.4)	(0.2)	(0.1)
Recoveries Collected	2.9	0	0
Accounts Receivable, Allowance for Credit Loss	$ 3.2	0.3	0.7	1.6
Home Equity Loan
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		(0.4)	(0.4)
Less loans charged-off		(0.1)	0
Recoveries Collected		0.3	0.3
Accounts Receivable, Allowance for Credit Loss		$ 1.2	$ 1.4	$ 1

Loans Held for Investment - S_3

Loans Held for Investment - Schedule of Contractual Aging of Loans by Portfolio (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	$ 39,800,000
Loans and Leases Receivable, Nonperforming, Accrual of Interest	0
Impaired Financing Receivable, Interest Income, Accrual Method	0
Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	19,600,000	$ 8,000,000
Loans and Leases Receivable, Collateral for Secured Borrowings	8,528,600,000	3,971,500,000
Commercial Real Estate Portfolio Segment [Member] \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	5,600,000	1,100,000
Commercial Real Estate Portfolio Segment [Member] \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	800,000	1,000,000
Commercial Real Estate Portfolio Segment [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,100,000	600,000
Commercial Real Estate Portfolio Segment [Member] \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	7,500,000	2,700,000
Commercial Real Estate Portfolio Segment [Member] \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	8,501,500,000	3,960,800,000
Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	3,700,000	700,000
Loans and Leases Receivable, Collateral for Secured Borrowings	386,200,000	247,800,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	159,200,000	113,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	117,900,000	41,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	29,700,000	34,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	17,000,000	15,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	11,100,000	20,200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	29,100,000	21,200,000
Financing Receivable, Excluding Accrued Interest, Revolving	22,200,000	1,200,000
Land Acquisition And Development Construction Financing Receivable [Member] \| Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	152,500,000	113,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	114,400,000	41,500,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	29,500,000	34,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	17,000,000	14,800,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	10,900,000	19,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	28,400,000	20,800,000
Financing Receivable, Excluding Accrued Interest, Revolving	22,200,000	1,200,000
Land Acquisition And Development Construction Financing Receivable [Member] \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,800,000	200,000
Land Acquisition And Development Construction Financing Receivable [Member] \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	0
Land Acquisition And Development Construction Financing Receivable [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	600,000	0
Land Acquisition And Development Construction Financing Receivable [Member] \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	2,400,000	200,000
Land Acquisition And Development Construction Financing Receivable [Member] \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	380,100,000	246,900,000
Residential Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	0	0
Loans and Leases Receivable, Collateral for Secured Borrowings	516,200,000	262,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	118,400,000	112,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	120,400,000	7,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	400,000	13,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	300,000	900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	400,000	400,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	6,200,000	0
Financing Receivable, Excluding Accrued Interest, Revolving	270,100,000	127,200,000
Residential Real Estate Construction Financing Receivable [Member] \| Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	118,400,000	112,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	119,900,000	7,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	400,000	13,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	300,000	900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	400,000	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	5,800,000	0
Financing Receivable, Excluding Accrued Interest, Revolving	270,100,000	127,200,000
Residential Real Estate Construction Financing Receivable [Member] \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,100,000	4,200,000
Residential Real Estate Construction Financing Receivable [Member] \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	0
Residential Real Estate Construction Financing Receivable [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	0
Residential Real Estate Construction Financing Receivable [Member] \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,100,000	4,200,000
Residential Real Estate Construction Financing Receivable [Member] \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	515,100,000	257,800,000
Commercial Real Estate Construction [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	0	0
Loans and Leases Receivable, Collateral for Secured Borrowings	1,042,000,000	498,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	461,800,000	209,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	399,200,000	141,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	112,800,000	118,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	45,900,000	27,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	400,000	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	500,000
Financing Receivable, Excluding Accrued Interest, Revolving	21,900,000	0
Commercial Real Estate Construction [Member] \| Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	442,700,000	209,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	374,800,000	141,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	89,700,000	118,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	45,900,000	27,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	400,000	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	500,000
Financing Receivable, Excluding Accrued Interest, Revolving	10,600,000	0
Commercial Real Estate Construction [Member] \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	7,500,000	0
Commercial Real Estate Construction [Member] \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	600,000	0
Commercial Real Estate Construction [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	0
Commercial Real Estate Construction [Member] \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	8,100,000	0
Commercial Real Estate Construction [Member] \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,033,900,000	498,000,000
Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	3,700,000	700,000
Loans and Leases Receivable, Collateral for Secured Borrowings	1,944,400,000	1,007,800,000
Real Estate Construction Financing Receivable [Member] \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	10,400,000	4,400,000
Real Estate Construction Financing Receivable [Member] \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	600,000	0
Real Estate Construction Financing Receivable [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	600,000	0
Real Estate Construction Financing Receivable [Member] \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	11,600,000	4,400,000
Real Estate Construction Financing Receivable [Member] \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,929,100,000	1,002,700,000
Residential Mortgage [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	6,400,000	2,900,000
Loans and Leases Receivable, Collateral for Secured Borrowings	2,188,300,000	1,538,200,000
Residential Mortgage [Member] \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	9,900,000	3,000,000
Residential Mortgage [Member] \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	2,100,000	800,000
Residential Mortgage [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,200,000	100,000
Residential Mortgage [Member] \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	13,200,000	3,900,000
Residential Mortgage [Member] \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	2,168,700,000	1,531,400,000
Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	7,600,000	4,900,000
Loans and Leases Receivable, Collateral for Secured Borrowings	794,900,000	213,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	204,200,000	62,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	185,800,000	38,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	115,500,000	37,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	68,000,000	23,300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	59,300,000	13,200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	119,600,000	33,300,000
Financing Receivable, Excluding Accrued Interest, Revolving	42,500,000	5,800,000
Agricultural Real Estate Financing Receivable [Member] \| Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	180,000,000	58,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	172,800,000	36,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	109,500,000	35,100,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	64,800,000	22,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	46,600,000	11,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	105,100,000	28,100,000
Financing Receivable, Excluding Accrued Interest, Revolving	31,400,000	4,900,000
Agricultural Real Estate Financing Receivable [Member] \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,100,000	1,900,000
Agricultural Real Estate Financing Receivable [Member] \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	6,100,000	200,000
Agricultural Real Estate Financing Receivable [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	0
Agricultural Real Estate Financing Receivable [Member] \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	7,200,000	2,100,000
Agricultural Real Estate Financing Receivable [Member] \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	780,100,000	206,900,000
Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	37,300,000	16,500,000
Loans and Leases Receivable, Collateral for Secured Borrowings	13,456,200,000	6,731,400,000
Real Estate Financing Receivable [Member] \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	27,000,000	10,400,000
Real Estate Financing Receivable [Member] \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	9,600,000	2,000,000
Real Estate Financing Receivable [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	2,900,000	700,000
Real Estate Financing Receivable [Member] \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	39,500,000	13,100,000
Real Estate Financing Receivable [Member] \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	13,379,400,000	6,701,800,000
Indirect consumer
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	2,700,000	1,700,000
Loans and Leases Receivable, Collateral for Secured Borrowings	829,700,000	737,600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	381,300,000	273,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	177,300,000	209,100,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	130,600,000	108,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	60,000,000	64,200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	33,800,000	37,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	46,700,000	45,400,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Indirect consumer \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	9,300,000	5,100,000
Indirect consumer \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	2,400,000	1,400,000
Indirect consumer \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	600,000	400,000
Indirect consumer \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	12,300,000	6,900,000
Indirect consumer \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	814,700,000	729,000,000
Other consumer
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	300,000	100,000
Loans and Leases Receivable, Collateral for Secured Borrowings	152,900,000	129,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	52,700,000	42,600,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	32,000,000	27,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	18,300,000	15,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	8,500,000	13,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	6,500,000	5,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	9,000,000	7,600,000
Financing Receivable, Excluding Accrued Interest, Revolving	25,900,000	16,900,000
Other consumer \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	800,000	500,000
Other consumer \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	300,000	200,000
Other consumer \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	100,000	100,000
Other consumer \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,200,000	800,000
Other consumer \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	151,400,000	128,300,000
Credit card consumer
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	0	0
Loans and Leases Receivable, Collateral for Secured Borrowings	75,900,000	64,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	178,100,000	139,600,000
Credit card consumer \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	800,000	600,000
Credit card consumer \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	400,000	200,000
Credit card consumer \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	600,000	500,000
Credit card consumer \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,800,000	1,300,000
Credit card consumer \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	74,100,000	63,600,000
Total consumer loans
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	3,000,000	1,800,000
Loans and Leases Receivable, Collateral for Secured Borrowings	1,058,500,000	931,700,000
Total consumer loans \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	10,900,000	6,200,000
Total consumer loans \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	3,100,000	1,800,000
Total consumer loans \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,300,000	1,000,000
Total consumer loans \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	15,300,000	9,000,000
Total consumer loans \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,040,200,000	920,900,000
Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	10,200,000	5,000,000
Loans and Leases Receivable, Collateral for Secured Borrowings	2,882,600,000	1,475,500,000
Commercial Portfolio Segment [Member] \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	7,100,000	4,900,000
Commercial Portfolio Segment [Member] \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,700,000	700,000
Commercial Portfolio Segment [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	2,100,000	1,100,000
Commercial Portfolio Segment [Member] \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	10,900,000	6,700,000
Commercial Portfolio Segment [Member] \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	2,861,500,000	1,463,800,000
Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	8,700,000	1,600,000
Loans and Leases Receivable, Collateral for Secured Borrowings	708,300,000	203,900,000
Agricultural Financing Receivable [Member] \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	800,000	700,000
Agricultural Financing Receivable [Member] \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	2,200,000	0
Agricultural Financing Receivable [Member] \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	100,000	0
Agricultural Financing Receivable [Member] \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	3,100,000	700,000
Agricultural Financing Receivable [Member] \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	696,500,000	201,600,000
Other, including overdrafts
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	0	0
Loans and Leases Receivable, Collateral for Secured Borrowings	9,200,000	1,500,000
Other, including overdrafts \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	0
Other, including overdrafts \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	0
Other, including overdrafts \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	0
Other, including overdrafts \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	0
Other, including overdrafts \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	9,200,000	1,500,000
Loans held for investment
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	59,200,000	24,900,000
Loans and Leases Receivable, Collateral for Secured Borrowings	18,114,800,000	9,344,000,000
Loans held for investment \| Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	45,800,000	22,200,000
Loans held for investment \| Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	16,600,000	4,500,000
Loans held for investment \| Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	6,400,000	2,800,000
Loans held for investment \| Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	68,800,000	29,500,000
Loans held for investment \| Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	17,986,800,000	9,289,600,000
Non Owner Occupied Loans
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,163,700,000	512,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	882,000,000	470,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	674,200,000	242,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	490,400,000	151,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	261,100,000	77,300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	907,600,000	425,000,000
Financing Receivable, Excluding Accrued Interest, Revolving	29,200,000	15,300,000
Non Owner Occupied Loans \| Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,162,600,000	507,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	861,300,000	452,200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	661,100,000	237,900,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	467,600,000	150,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	241,500,000	76,300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	890,400,000	409,000,000
Financing Receivable, Excluding Accrued Interest, Revolving	$ 29,200,000	$ 15,300,000

Loans Held for Investment - S_4

Loans Held for Investment - Schedule of Troubled Debt Restructurings (Details)	12 Months Ended
	Dec. 31, 2022 USD ($) note	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Loans and Leases Receivable, Troubled Debt Restructuring
Loans renegotiated in troubled debt restructurings	$ 64,600,000	$ 6,200,000
Loans renegotiated in troubled debt restructurings, non-accrual loans	4,200,000	3,900,000
Loans renegotiated in troubled debt restructurings, accrual loans	$ 60,400,000	2,300,000
Number of notes under troubled debt restructurings \| note	12
Charge-offs directly related to modified loans	$ 5,700,000	$ 0	$ 0
Financing Receivable, Troubled Debt Restructuring, Postmodification	71,700,000
Financing Receivable, Troubled Debt Restructuring, Commitment to Lend	0
Balance of notes for which there was a payment default	0
Impaired Financing Receivable, Recorded Investment	743,300,000
Financing Receivable, Allowance for Credit Loss, Noncurrent	$ 100,000
Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Number of notes under troubled debt restructurings \| note	4
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 53,700,000
Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Number of notes under troubled debt restructurings \| note	2
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 9,000,000
Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Number of notes under troubled debt restructurings \| note	3
Concessions in troubled debt restructurings, amount	$ 2,500,000
Agriculture
Loans and Leases Receivable, Troubled Debt Restructuring
Number of notes under troubled debt restructurings \| note	1
Concessions in troubled debt restructurings, amount	$ 5,900,000
Residential Real Estate
Loans and Leases Receivable, Troubled Debt Restructuring
Number of notes under troubled debt restructurings \| note	2
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 600,000
Interest Only Period Concession
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	3,200,000
Interest Only Period Concession \| Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	3,200,000
Interest Only Period Concession \| Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Concessions in troubled debt restructurings, amount	0
Interest Only Period Concession \| Agriculture
Loans and Leases Receivable, Troubled Debt Restructuring
Concessions in troubled debt restructurings, amount	0
Extension of terms or maturity
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	15,700,000
Extension of terms or maturity \| Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	4,200,000
Extension of terms or maturity \| Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	9,000,000
Extension of terms or maturity \| Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Concessions in troubled debt restructurings, amount	1,900,000
Extension of terms or maturity \| Agriculture
Loans and Leases Receivable, Troubled Debt Restructuring
Concessions in troubled debt restructurings, amount	0
Extension of terms or maturity \| Residential Real Estate
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	600,000
Interest rate adjustment
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	0
Interest rate adjustment \| Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	0
Interest rate adjustment \| Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	0
Interest rate adjustment \| Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Concessions in troubled debt restructurings, amount	0
Interest rate adjustment \| Agriculture
Loans and Leases Receivable, Troubled Debt Restructuring
Concessions in troubled debt restructurings, amount	0
Interest rate adjustment \| Residential Real Estate
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	0
Other
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	52,800,000
Other \| Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	46,300,000
Other \| Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Concessions in troubled debt restructurings, amount	600,000
Other \| Agriculture
Loans and Leases Receivable, Troubled Debt Restructuring
Concessions in troubled debt restructurings, amount	5,900,000
Interest Only Period \| Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	0
Interest Only Period \| Residential Real Estate
Loans and Leases Receivable, Troubled Debt Restructuring
Concessions in troubled debt restructurings, amount	0
Other Loan Restructuring Modification \| Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	0
Other Loan Restructuring Modification \| Residential Real Estate
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 0

Loans - Schedule of Recorded In

Loans - Schedule of Recorded Investment in Criticized Loans by Class and Credit Quality Indicator (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Commitments to Purchase or Sell	$ 0
Proceeds from Sale of Loans and Leases Held-for-investment	0
Non Owner Occupied Loans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	4,408,200,000	$ 1,893,600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,163,700,000	512,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	882,000,000	470,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	674,200,000	242,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	490,400,000	151,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	261,100,000	77,300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	907,600,000	425,000,000
Financing Receivable, Excluding Accrued Interest, Revolving	29,200,000	15,300,000
Commercial Real Estate Owner Occupied
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	3,153,500,000	1,656,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	812,700,000	457,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	737,300,000	322,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	548,500,000	241,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	281,300,000	163,800,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	179,900,000	100,700,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	574,000,000	356,600,000
Financing Receivable, Excluding Accrued Interest, Revolving	19,800,000	14,200,000
Commercial Real Estate Multifamily
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	966,900,000	421,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	369,200,000	129,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	204,900,000	118,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	189,000,000	43,900,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	52,100,000	15,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	35,000,000	36,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	115,700,000	76,700,000
Financing Receivable, Excluding Accrued Interest, Revolving	1,000,000	1,500,000
Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	386,200,000	247,800,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	159,200,000	113,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	117,900,000	41,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	29,700,000	34,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	17,000,000	15,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	11,100,000	20,200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	29,100,000	21,200,000
Financing Receivable, Excluding Accrued Interest, Revolving	22,200,000	1,200,000
Residential Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	516,200,000	262,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	118,400,000	112,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	120,400,000	7,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	400,000	13,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	300,000	900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	400,000	400,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	6,200,000	0
Financing Receivable, Excluding Accrued Interest, Revolving	270,100,000	127,200,000
Commercial Real Estate Construction [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	1,042,000,000	498,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	461,800,000	209,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	399,200,000	141,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	112,800,000	118,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	45,900,000	27,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	400,000	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	500,000
Financing Receivable, Excluding Accrued Interest, Revolving	21,900,000	0
Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	794,900,000	213,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	204,200,000	62,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	185,800,000	38,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	115,500,000	37,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	68,000,000	23,300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	59,300,000	13,200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	119,600,000	33,300,000
Financing Receivable, Excluding Accrued Interest, Revolving	42,500,000	5,800,000
Commercial and Floor Plans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	2,249,400,000	1,132,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	527,700,000	396,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	370,300,000	179,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	219,400,000	96,900,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	132,100,000	76,900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	124,400,000	50,700,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	178,100,000	97,700,000
Financing Receivable, Excluding Accrued Interest, Revolving	697,400,000	234,300,000
Commercial Purpose Secured by 1-4 Family
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	532,900,000	269,600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	192,000,000	96,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	136,000,000	56,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	72,000,000	28,600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	30,900,000	24,200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	32,200,000	15,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	40,900,000	34,100,000
Financing Receivable, Excluding Accrued Interest, Revolving	28,900,000	14,500,000
Agriculture
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	706,400,000	202,400,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	176,100,000	40,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	67,600,000	21,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	35,000,000	9,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	12,200,000	8,300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	10,100,000	2,700,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	3,300,000	2,000,000
Financing Receivable, Excluding Accrued Interest, Revolving	402,100,000	118,500,000
Residential Real Estate 1-4 Family
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	1,639,400,000	1,143,600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	258,900,000	360,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	490,500,000	477,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	541,700,000	74,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	98,500,000	27,500,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	32,300,000	25,900,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	217,500,000	177,300,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Residential Real Estate 1-4 Family \| Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	1,634,600,000	1,142,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	258,900,000	360,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	490,300,000	477,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	541,600,000	74,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	98,000,000	27,500,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	32,000,000	25,700,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	213,800,000	176,500,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Residential Real Estate 1-4 Family \| Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	4,800,000	1,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	200,000	300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	100,000	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	500,000	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	300,000	200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	3,700,000	800,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Home Equity Loan
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	548,900,000	394,600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	24,400,000	11,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	8,300,000	7,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	5,400,000	4,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	5,700,000	4,800,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	5,700,000	4,200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	16,400,000	12,500,000
Financing Receivable, Excluding Accrued Interest, Revolving	483,000,000	350,700,000
Home Equity Loan \| Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	546,100,000	392,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	23,800,000	11,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	8,000,000	7,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	5,200,000	3,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	5,500,000	4,800,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	5,600,000	3,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	15,200,000	12,000,000
Financing Receivable, Excluding Accrued Interest, Revolving	482,800,000	350,700,000
Home Equity Loan \| Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	2,800,000	1,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	600,000	300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	300,000	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	200,000	300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	200,000	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	100,000	600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,200,000	500,000
Financing Receivable, Excluding Accrued Interest, Revolving	200,000	0
Indirect consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	829,700,000	737,600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	381,300,000	273,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	177,300,000	209,100,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	130,600,000	108,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	60,000,000	64,200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	33,800,000	37,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	46,700,000	45,400,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Indirect consumer \| Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	826,300,000	735,500,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	380,300,000	272,600,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	176,400,000	208,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	130,000,000	108,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	59,700,000	64,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	33,600,000	37,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	46,300,000	45,000,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Indirect consumer \| Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	3,400,000	2,100,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,000,000	500,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	900,000	500,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	600,000	400,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	300,000	200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	200,000	100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	400,000	400,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Other consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	152,900,000	129,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	52,700,000	42,600,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	32,000,000	27,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	18,300,000	15,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	8,500,000	13,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	6,500,000	5,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	9,000,000	7,600,000
Financing Receivable, Excluding Accrued Interest, Revolving	25,900,000	16,900,000
Other consumer \| Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	152,400,000	129,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	52,600,000	42,500,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	31,900,000	27,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	18,200,000	15,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	8,500,000	13,300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	6,500,000	5,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	8,900,000	7,600,000
Financing Receivable, Excluding Accrued Interest, Revolving	25,800,000	16,900,000
Other consumer \| Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	500,000	200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	100,000	100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	100,000	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	100,000	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	100,000	0
Financing Receivable, Excluding Accrued Interest, Revolving	100,000	0
Credit card consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	178,100,000	139,600,000
Credit card consumer \| Total consumer loans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	75,900,000	64,900,000
Credit card consumer \| Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	100,300,000	73,200,000
Credit card consumer \| Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,900,000	1,500,000
Credit card consumer \| Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	177,300,000	139,000,000
Credit card consumer \| Performing Financial Instruments \| Total consumer loans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	75,400,000	64,400,000
Credit card consumer \| Performing Financial Instruments \| Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	100,000,000	73,100,000
Credit card consumer \| Performing Financial Instruments \| Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,900,000	1,500,000
Credit card consumer \| Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	800,000	600,000
Credit card consumer \| Nonperforming Financial Instruments \| Total consumer loans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	500,000	500,000
Credit card consumer \| Nonperforming Financial Instruments \| Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	300,000	100,000
Credit card consumer \| Nonperforming Financial Instruments \| Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	0
Pass \| Non Owner Occupied Loans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		1,849,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,162,600,000	507,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	861,300,000	452,200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	661,100,000	237,900,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	467,600,000	150,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	241,500,000	76,300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	890,400,000	409,000,000
Financing Receivable, Excluding Accrued Interest, Revolving	29,200,000	15,300,000
Pass \| Commercial Real Estate Owner Occupied
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	3,047,200,000	1,584,800,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	793,000,000	452,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	718,700,000	314,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	533,900,000	235,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	266,300,000	151,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	165,800,000	94,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	551,300,000	322,500,000
Financing Receivable, Excluding Accrued Interest, Revolving	18,200,000	14,200,000
Pass \| Commercial Real Estate Multifamily
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	964,900,000	421,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	369,200,000	129,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	204,900,000	118,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	189,000,000	43,900,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	52,100,000	15,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	35,000,000	36,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	113,700,000	76,700,000
Financing Receivable, Excluding Accrued Interest, Revolving	1,000,000	1,500,000
Pass \| Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	374,900,000	245,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	152,500,000	113,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	114,400,000	41,500,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	29,500,000	34,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	17,000,000	14,800,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	10,900,000	19,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	28,400,000	20,800,000
Financing Receivable, Excluding Accrued Interest, Revolving	22,200,000	1,200,000
Pass \| Residential Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	515,300,000	261,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	118,400,000	112,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	119,900,000	7,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	400,000	13,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	300,000	900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	400,000	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	5,800,000	0
Financing Receivable, Excluding Accrued Interest, Revolving	270,100,000	127,200,000
Pass \| Commercial Real Estate Construction [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	964,100,000	498,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	442,700,000	209,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	374,800,000	141,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	89,700,000	118,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	45,900,000	27,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	400,000	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	500,000
Financing Receivable, Excluding Accrued Interest, Revolving	10,600,000	0
Pass \| Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	710,200,000	197,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	180,000,000	58,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	172,800,000	36,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	109,500,000	35,100,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	64,800,000	22,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	46,600,000	11,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	105,100,000	28,100,000
Financing Receivable, Excluding Accrued Interest, Revolving	31,400,000	4,900,000
Pass \| Commercial and Floor Plans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	2,122,300,000	1,091,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	501,700,000	394,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	358,900,000	165,700,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	214,400,000	94,500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	124,300,000	73,500,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	120,300,000	47,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	171,100,000	91,300,000
Financing Receivable, Excluding Accrued Interest, Revolving	631,600,000	224,700,000
Pass \| Commercial Purpose Secured by 1-4 Family
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	524,700,000	262,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	191,700,000	94,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	134,500,000	55,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	69,800,000	27,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	30,400,000	23,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	29,900,000	15,300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	39,500,000	32,200,000
Financing Receivable, Excluding Accrued Interest, Revolving	28,900,000	14,400,000
Pass \| Agriculture
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	616,100,000	178,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	127,200,000	35,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	59,700,000	16,200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	31,800,000	9,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	10,600,000	5,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	8,600,000	2,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	3,100,000	1,600,000
Financing Receivable, Excluding Accrued Interest, Revolving	375,100,000	108,900,000
Pass \| Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	4,313,700,000
Other Assets Especial Mentioned \| Non Owner Occupied Loans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	22,100,000	9,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,000,000	200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	6,800,000	3,100,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	2,300,000	2,100,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	4,600,000	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	7,400,000	3,600,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Other Assets Especial Mentioned \| Commercial Real Estate Owner Occupied
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	55,700,000	30,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	10,900,000	1,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	14,200,000	3,200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	12,300,000	1,500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	6,100,000	7,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	5,600,000	3,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	5,500,000	13,800,000
Financing Receivable, Excluding Accrued Interest, Revolving	1,100,000	0
Other Assets Especial Mentioned \| Commercial Real Estate Multifamily
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	1,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,700,000
Financing Receivable, Excluding Accrued Interest, Revolving	0
Other Assets Especial Mentioned \| Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	7,200,000	500,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	6,700,000	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	100,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	200,000	100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	300,000	300,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Other Assets Especial Mentioned \| Commercial Real Estate Construction [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	36,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	2,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	23,100,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	11,300,000
Other Assets Especial Mentioned \| Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	51,100,000	4,600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	22,400,000	100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	700,000	1,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,200,000	1,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	2,600,000	100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	10,000,000	100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	3,200,000	900,000
Financing Receivable, Excluding Accrued Interest, Revolving	11,000,000	900,000
Other Assets Especial Mentioned \| Commercial and Floor Plans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	52,700,000	26,100,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	15,900,000	800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	6,800,000	11,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,300,000	800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	4,400,000	800,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	900,000	3,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	4,900,000	2,300,000
Financing Receivable, Excluding Accrued Interest, Revolving	18,500,000	7,000,000
Other Assets Especial Mentioned \| Commercial Purpose Secured by 1-4 Family
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	5,200,000	1,600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	100,000	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,200,000	200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	2,100,000	200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	200,000	500,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,400,000	100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	200,000	600,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Other Assets Especial Mentioned \| Agriculture
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	56,800,000	12,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	26,100,000	200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,800,000	4,100,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	400,000	100,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,000,000	400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	300,000	600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	300,000
Financing Receivable, Excluding Accrued Interest, Revolving	26,200,000	7,000,000
Substandard \| Non Owner Occupied Loans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	72,400,000	35,600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	100,000	3,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	13,900,000	15,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	10,800,000	2,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	18,200,000	700,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	19,600,000	1,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	9,800,000	12,400,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Substandard \| Commercial Real Estate Owner Occupied
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	48,800,000	41,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	8,400,000	3,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	3,000,000	4,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	2,300,000	4,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	8,900,000	5,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	8,500,000	2,700,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	17,200,000	20,300,000
Financing Receivable, Excluding Accrued Interest, Revolving	500,000	0
Substandard \| Commercial Real Estate Multifamily
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	300,000
Financing Receivable, Excluding Accrued Interest, Revolving	0
Substandard \| Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	900,000	2,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	300,000	200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	200,000	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	400,000	100,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Substandard \| Residential Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	900,000	800,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	500,000	400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	400,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	400,000	0
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Substandard \| Commercial Real Estate Construction [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	41,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	16,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	24,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	0
Substandard \| Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	32,300,000	11,600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,800,000	4,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	12,300,000	400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	3,500,000	1,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	600,000	600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	2,700,000	1,300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	11,300,000	4,300,000
Financing Receivable, Excluding Accrued Interest, Revolving	100,000	0
Substandard \| Commercial and Floor Plans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	72,700,000	15,600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	9,800,000	1,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	3,300,000	2,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	3,700,000	1,600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	3,400,000	2,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	3,200,000	600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	2,100,000	4,100,000
Financing Receivable, Excluding Accrued Interest, Revolving	47,200,000	2,600,000
Substandard \| Commercial Purpose Secured by 1-4 Family
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	3,000,000	5,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	200,000	1,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	300,000	1,200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	100,000	600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	300,000	600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	900,000	200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,200,000	1,300,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	100,000
Substandard \| Agriculture
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	33,000,000	11,400,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	22,800,000	4,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	4,600,000	700,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	2,800,000	600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	600,000	2,500,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,200,000	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	200,000	100,000
Financing Receivable, Excluding Accrued Interest, Revolving	800,000	$ 2,600,000
Doubtful \| Commercial Real Estate Owner Occupied
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	1,800,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	0
Doubtful \| Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	3,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	3,200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	0
Doubtful \| Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	1,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	0
Doubtful \| Commercial and Floor Plans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	1,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	100,000
Doubtful \| Agriculture
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	500,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	500,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	$ 0

Loans Held for Investment - S_5

Loans Held for Investment - Schedule of PCD Loans (Details) $ in Millions	Feb. 01, 2022 USD ($)
Receivables [Abstract]
Purchase Price (Initial Fair Value)	$ 623.3
Allowance for Credit Losses	(298.2)
Non-Credit Discount at Acquisition	57.7
Par Value (Unpaid Principal Balance)	979.2
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Allowance for Loan Losses, Decreases	238.7
Business Combination, Impact on Purchased Credit Deteriorated Loans	59.5
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Difference Between Amortized Cost Basis and Unpaid Principal Balance	39.6
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Interest Applied to Principal	$ 18.1

Loans - Schedule of Recorded _2

Loans - Schedule of Recorded Investment in Impaired Loans (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	$ 8,528.6	$ 3,971.5
Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	386.2	247.8
Residential Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	516.2	262
Commercial Real Estate Construction [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	1,042	498
Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	1,944.4	1,007.8
Residential Mortgage [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	2,188.3	1,538.2
Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	794.9	213.9
Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	13,456.2	6,731.4
Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	708.3	203.9
Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	2,882.6	1,475.5
Loans held for investment
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	18,114.8	9,344
Indirect consumer
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	829.7	737.6
Other consumer
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	152.9	129.2
Collateral
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	39.1	11.7
Collateral \| Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	27.2	8.2
Collateral \| Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	7.3	0.7
Collateral \| Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	4.6	2.8
Business Assets Pledged as Collateral \| Collateral
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	7.1	3
Business Assets Pledged as Collateral \| Collateral \| Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	1.9	1.2
Business Assets Pledged as Collateral \| Collateral \| Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	2.1	0
Business Assets Pledged as Collateral \| Collateral \| Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	3.1	1.8
Real Property Pledged as Collateral \| Collateral
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	32	8.7
Real Property Pledged as Collateral \| Collateral \| Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	25.3	7
Real Property Pledged as Collateral \| Collateral \| Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	5.2	0.7
Real Property Pledged as Collateral \| Collateral \| Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	1.5	1
Other Property \| Collateral
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	0
Other Property \| Collateral \| Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	0
Other Property \| Collateral \| Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	0
Other Property \| Collateral \| Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	$ 0	$ 0

Loans Held for Investment - Nar

Loans Held for Investment - Narrative (Details) - USD ($)	12 Months Ended
Loans Held for Investment - Narrative (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Receivables [Abstract]
Loans renegotiated in troubled debt restructurings	$ 64,600,000	$ 6,200,000
Loans renegotiated in troubled debt restructurings, non-accrual loans	4,200,000	3,900,000
Loans renegotiated in troubled debt restructurings, accrual loans	60,400,000	2,300,000
Accounts and Financing Receivable, after Allowance for Credit Loss, Noncurrent	1,100,000
Financing Receivable, Troubled Debt Restructuring, Commitment to Lend	0
Financing Receivable, Allowance for Credit Loss, Noncurrent	100,000
Financing Receivable, Troubled Debt Restructuring, Postmodification	71,700,000
Charge-offs directly related to modified loans	5,700,000	$ 0	$ 0
Balance of notes for which there was a payment default	0
Impaired Financing Receivable, Recorded Investment	$ 743,300,000

Premises and Equipment (Details

Premises and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
Premises and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment
Depreciation	$ 35.1	$ 28	$ 25.8
Premises and equipment, gross	666.9	495.8
Less accumulated depreciation	(222.2)	(196.2)
Premises and equipment, net	444.7	299.6
Land
Property, Plant and Equipment
Premises and equipment, gross	86.7	52
Buildings and improvements
Property, Plant and Equipment
Premises and equipment, gross	469.2	346.8
Furniture and equipment
Property, Plant and Equipment
Premises and equipment, gross	$ 111	$ 97

Company-Owned Life Insurance (D

Company-Owned Life Insurance (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Schedule of Company - Owned Life Insurance, By Type
Total	$ 497.9	$ 301.5
Key executive, principal shareholder
Schedule of Company - Owned Life Insurance, By Type
Cash surrender value of life insurance	3.2	3.2
Key executive split dollar
Schedule of Company - Owned Life Insurance, By Type
Cash surrender value of life insurance	7.1	7.1
FIB \| Group life
Schedule of Company - Owned Life Insurance, By Type
Cash surrender value of life insurance	$ 487.6	$ 291.2

Other Real Estate Owned (Detail

Other Real Estate Owned (Details) - USD ($) $ in Millions	12 Months Ended
Other Real Estate Owned (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Repossessed Assets [Abstract]
Real Estate Acquired Through Foreclosure, Valuation Adjustments	$ 2.8	$ 0
Real Estate Acquired Through Foreclosure [Roll Forward]
Balance at beginning of year	2	2.5	$ 8.5
OREO acquired through acquisitions	15.8	0	0
Additions	0.4	0.9	3.3
Valuation adjustments	(2.8)	0	(0.1)
Dispositions	(2.7)	(1.4)	(9.2)
Balance at end of year	12.7	2	2.5
Write-downs of OREO	(2.8)	$ 0	$ (0.1)
Mortgage Loans in Process of Foreclosure, Amount	0
Carrying value of foreclosed OREO	$ 0

Derivatives and Hedging Activ_2

Derivatives and Hedging Activities - Notional Amounts and Estimated Fair Values of Derivatives (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Derivative Asset, Notional Amount	$ 2,290.7	$ 1,691.2
Derivative Assets, Estimated Fair Value	45.2	28.1
Derivative Liability, Notional Amount	2,449	1,103.9
Derivative Liabilities, Estimated Fair Value	159.6	18.2
Derivative Instruments and Hedges, Assets	191.9	695.6
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	8.1	(4.4)
Not Designated as Hedging Instrument \| Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Asset, Notional Amount	1,728.1	913.9
Derivative Assets, Estimated Fair Value	41.6	22.2
Derivative Liability, Notional Amount	1,728.1	913.9
Derivative Liabilities, Estimated Fair Value	153.9	18.1
Not Designated as Hedging Instrument \| Interest Rate Lock Commitments [Member]
Derivative [Line Items]
Derivative Asset, Notional Amount	0	77.3
Derivative Assets, Estimated Fair Value	0	1.8
Derivative Liability, Notional Amount	14.8	0
Derivative Liabilities, Estimated Fair Value	0	0
Not Designated as Hedging Instrument \| Forward Contracts [Member]
Derivative [Line Items]
Derivative Asset, Notional Amount	12.6	0
Derivative Liability, Notional Amount	0	102.4
Derivative Liabilities, Estimated Fair Value	0	0
Designated as Hedging Instrument \| Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Asset, Notional Amount	550	700
Derivative Assets, Estimated Fair Value	3.5	4.1
Derivative Liability, Notional Amount	300	87.6
Derivative Liabilities, Estimated Fair Value	$ 0.3	$ 0.1

Derivatives and Hedging Activ_3

Derivatives and Hedging Activities - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Derivative liability, notional amount	$ 2,449	$ 1,103.9
Derivative, Collateral, Right to Reclaim Securities	0	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	(2.2)
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	5.4
Derivative Instruments and Hedges, Assets	191.9	695.6
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	8.1	(4.4)
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	0	$ 0
Two-Year Forward Starting, Three-year Pay Fixed Interest Rate Swap
Derivative [Line Items]
Derivative Instruments and Hedges, Assets	500
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	23.3
Three-Year Forward Starting, Four-Year Pay Fixed Interest Rate Swap
Derivative [Line Items]
Derivative Instruments and Hedges, Assets	200
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	8.5
Interest Rate Collars
Derivative [Line Items]
Derivative Instruments and Hedges, Assets	300
Forward Starting Receive-Fixed Hedges
Derivative [Line Items]
Derivative Instruments and Hedges, Assets	850
Collateral Pledged
Derivative [Line Items]
Derivative, Fair Value, Net	0
Derivative, Collateral, Right to Reclaim Securities	$ 0

Derivatives and Hedging Activ_4

Derivatives and Hedging Activities - Schedule of Master Netting Arrangements (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross Asset	$ 45.2	$ 28.1
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset, Total	45.2	28.1
Derivative, Collateral, Obligation to Return Securities	0	0
Derivative, Collateral, Obligation to Return Cash	45.1	8
Derivative Asset, Fair Value, Amount Offset Against Collateral, Total	0.1	20.1
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	159.6	18.2
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability, Total	159.6	18.2
Derivative, Collateral, Right to Reclaim Securities	0	0
Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral, Total	159.6	18.2
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral [Abstract]
Securities Sold under Agreements to Repurchase, Gross	1,052.9	1,051.1
Securities Sold under Agreements to Repurchase, Asset	0	0
Securities Sold under Agreements to Repurchase, Total	1,052.9	1,051.1
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	0	0
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Cash	1,052.9	1,051.1
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral, Total	0	0
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Gross	1,212.5	1,069.3
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Asset	0	0
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Total	1,212.5	1,069.3
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Collateral, Right to Reclaim Securities	0	0
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Collateral, Right to Reclaim Cash	1,052.9	1,051.1
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Amount Offset Against Collateral, Total	159.6	18.2
Derivative Asset, Notional Amount	2,290.7	1,691.2
Derivative Assets, Estimated Fair Value	45.2	28.1
Derivative Liability, Notional Amount	2,449	1,103.9
Derivative Liabilities, Estimated Fair Value	159.6	18.2
Collateral Pledged
Offsetting Derivative Liabilities [Abstract]
Derivative, Collateral, Right to Reclaim Securities	0
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative, Fair Value, Net	0
Interest Rate Swap [Member]
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross Asset	45.1	26.3
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset, Total	45.1	26.3
Derivative, Collateral, Obligation to Return Securities	0	0
Derivative, Collateral, Obligation to Return Cash	45.1	8
Derivative Asset, Fair Value, Amount Offset Against Collateral, Total	0	18.3
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	159.6	18.2
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability, Total	159.6	18.2
Derivative, Collateral, Right to Reclaim Securities	0	0
Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral, Total	159.6	18.2
Interest Rate Swap [Member] \| Not Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Asset, Notional Amount	1,728.1	913.9
Derivative Assets, Estimated Fair Value	41.6	22.2
Derivative Liability, Notional Amount	1,728.1	913.9
Derivative Liabilities, Estimated Fair Value	153.9	18.1
Interest Rate Swap [Member] \| Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Asset, Notional Amount	550	700
Derivative Assets, Estimated Fair Value	3.5	4.1
Derivative Liability, Notional Amount	300	87.6
Derivative Liabilities, Estimated Fair Value	0.3	0.1
Mortgage related derivatives
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross Asset	0.1	1.8
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset, Total	0.1	1.8
Derivative, Collateral, Obligation to Return Securities	0	0
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral, Total	0.1	1.8
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	0
Derivative Liability, Fair Value, Gross Asset	0
Derivative Liability, Total	0
Derivative, Collateral, Right to Reclaim Securities	0
Derivative, Collateral, Right to Reclaim Cash	0
Derivative Liability, Fair Value, Amount Offset Against Collateral, Total	0
Forward Contracts [Member] \| Not Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Asset, Notional Amount	12.6	0
Derivative Liability, Notional Amount	0	102.4
Derivative Liabilities, Estimated Fair Value	0	0
Derivative, Fair Value, Net	0.1	0
Interest Rate Collars \| Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Liability, Notional Amount	300	0
Derivative Liabilities, Estimated Fair Value	5.4	0
Risk Participation Agreements
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	0
Derivative Liability, Fair Value, Gross Asset	0
Derivative Liability, Total	0
Derivative, Collateral, Right to Reclaim Securities	0
Derivative, Collateral, Right to Reclaim Cash	0
Derivative Liability, Fair Value, Amount Offset Against Collateral, Total	0
Risk Participation Agreements \| Not Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Liability, Notional Amount	106.1	0
Derivative Liabilities, Estimated Fair Value	0	0
Interest Rate Lock Commitments [Member] \| Not Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Asset, Notional Amount	0	77.3
Derivative Assets, Estimated Fair Value	0	1.8
Derivative Liability, Notional Amount	14.8	0
Derivative Liabilities, Estimated Fair Value	$ 0	$ 0

Derivatives and Hedging Activ_5

Derivatives and Hedging Activities - Pre-tax Gains and Losses on Derivative Contracts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ (46.3)
Not Designated as Hedging Instrument
Derivative [Line Items]
Fee Income on Derivatives	5.9	$ 3.1
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ (1.7)	$ (0.5)

Mortgage Servicing Rights - Sch

Mortgage Servicing Rights - Schedule of Mortgage Servicing Rights (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Servicing Asset at Amortized Value, Balance [Roll Forward]
Balance at end of year, net of valuation reserve	$ 31.1	$ 28.2
Mortgage loans
Servicing Asset at Amortized Value, Balance [Roll Forward]
Servicing asset at amortized cost, before valuation reserve, beginning	31.6	34.3	$ 30.6
Originations of mortgage servicing rights	2.5	3.7	11.7
Amortization expense	(4.3)	(6.4)	(8)
Servicing asset at amortized cost, before valuation reserve, ending	31.1	31.6	34.3
Acquisition of mortgage servicing rights	1.3	0	0
Less valuation reserve	0	(3.4)	(10.3)
Balance at end of year, net of valuation reserve	31.1	28.2	24
Principal balance of serviced loans underlying mortgage servicing rights	$ 3,259.8	$ 3,203.7	$ 3,585.5
Mortgage servicing rights as a percentage of serviced loans	0.0095	0.0088	0.0067

Mortgage Servicing Rights - Nar

Mortgage Servicing Rights - Narrative (Details) - Mortgage loans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]
Mortgage servicing rights, fair value	$ 37.4	$ 28.2
Servicing asset at fair value, assumptions used to estimate fair value, weighted average life	7 years 7 months 6 days	5 years 10 months 24 days
Impairment reversals	$ (3.4)	$ (6.9)	$ (9.9)
Permanent impairment charged against carrying value	$ 0
Minimum
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]
Servicing assets at fair value, assumptions used to estimate fair value, discount rate	11.80%	8.60%
Servicing assets at fair value, assumptions used to estimate fair value, prepayment speed	0.50%	0.70%
Maximum [Member]
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]
Servicing assets at fair value, assumptions used to estimate fair value, discount rate	13.50%	10.40%
Servicing assets at fair value, assumptions used to estimate fair value, prepayment speed	3.40%	2%

Deposits (Details)

Deposits (Details) - USD ($) $ in Thousands	12 Months Ended
Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deposits, by Type [Abstract]
Non-interest bearing demand	$ 7,560,000	$ 5,568,300
Interest bearing:
Demand	7,205,900	4,753,200
Savings	8,379,300	4,981,600
Total	438,000	186,700
Time, other	1,490,400	779,800
Total interest bearing	17,513,600	10,701,300
Total deposits	25,073,600	16,269,600
Brokered time deposits	0
Time deposits obtained through Certificate of Deposit Account Registry Service (CDARS)	36,600	104,500
Time deposits of $250,000 or more	438,000	186,700
FDIC deposit insurance limit	250,000
Time, $250 and Over
Due within 3 months or less	47,800
Due after 3 months and within 6 months	34,600
Due after 6 months and within 12 months	283,900
Due within 2024	55,000
Due within 2025	10,700
Due within 2026	4,800
Due within 2027 and thereafter	1,200
Total	438,000	186,700
Total Time
Due within 3 months or less	311,800
Due after 3 months and within 6 months	215,400
Due after 6 months and within 12 months	1,005,400
Due within 2024	282,800
Due within 2025	69,200
Due within 2026	27,800
Due within 2027 and thereafter	16,000
Total	1,928,400
Interest expense, time deposits, $100,000 or more	$ 2,500	$ 900	$ 2,700

Long-Term Debt and Other Borr_3

Long-Term Debt and Other Borrowed Funds (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	May 31, 2020
Debt Instrument
Stated interest rate			5.25%
Long-term debt	$ 98.9	$ 98.7
Long-term debt and capital lease obligations	120.8	112.4
Fiscal Year Maturities of Long-term Debt
2018	0.1
2019	0.1
2020	0.1
2021	0.1
2022	0.2
Thereafter	120.2
Long-term debt and capital lease obligations	120.8	112.4
Advances from FHLB	2,327	0
Other borrowings	2,327	0
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	1.1
Other Borrowings	0
Federal Home Loan Bank Advances	$ 0
FIB
Fiscal Year Maturities of Long-term Debt
Ownership percentage in subsidiary	99.90%
Parent
Debt Instrument
Long-term debt	$ 98.9	$ 98.7
4.60% variable rate overnight borrowings
Debt Instrument
Stated interest rate	4.60%
Fiscal Year Maturities of Long-term Debt
Advances from FHLB	$ 827
4.48% fixed rate borrowings in tenors up to one-month
Debt Instrument
Stated interest rate	4.48%
Fiscal Year Maturities of Long-term Debt
Advances from FHLB	$ 1,500
Capital lease obligations \| Capital Lease Obligation, 8.00% \| Subsidiaries
Debt Instrument
Stated interest rate		8%
Finance Lease, Liability	1	$ 1
Notes payable \| Subsidiaries
Fiscal Year Maturities of Long-term Debt
Long Term Debt, Acquired or Assumed	20.9	12.7
Notes payable \| Note Payable, 1.30%, maturing March 31, 2038 [Member] \| Subsidiaries
Debt Instrument
Long-term debt	2	2
Notes payable \| Note Payable, 1.30%, Maturing June 1, 2034 [Member] \| Subsidiaries
Debt Instrument
Long-term debt	$ 0.6	0.6
Notes payable \| Note Payable, One Percent \| Subsidiaries
Debt Instrument
Stated interest rate	1%
Notes payable \| Note Payable, 2.28% \| Subsidiaries
Debt Instrument
Long-term debt	$ 0	5
Notes payable \| Note Payable, 1.00% \| Subsidiaries
Debt Instrument
Long-term debt	$ 5.1	5.1
Notes payable \| Note Payable, One Point Three Percent \| Subsidiaries
Debt Instrument
Stated interest rate	1.30%
Notes payable \| Note Payable, One Point Three Zero Percent \| Subsidiaries
Debt Instrument
Stated interest rate	1.30%
Notes payable \| Note Payable, Three Point Two Five Percent \| Subsidiaries
Debt Instrument
Stated interest rate	3.25%
Notes payable \| Note Payable, 1.12%, Maturing December 31, 2045 \| Subsidiaries
Debt Instrument
Long-term debt	$ 6.8	0
Notes payable \| Note Payable, 1.35%, Maturing December 31, 2046 \| Subsidiaries
Debt Instrument
Long-term debt	6.4	$ 0
Federal Home Loan Bank \| Notes Payable to FHLB \| Subsidiaries
Fiscal Year Maturities of Long-term Debt
FHLB, advances, maximum amount available	4,768
Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds	2,441
Secured Debt
Fiscal Year Maturities of Long-term Debt
Line of credit facility, maximum borrowing capacity	763.3
Federal Funds Purchased
Fiscal Year Maturities of Long-term Debt
Line of credit facility, maximum borrowing capacity	235
Unsecured Debt [Member]
Fiscal Year Maturities of Long-term Debt
Line of credit facility, maximum borrowing capacity	$ 100
Subordinated term loan \| Subordinated Notes Due May 2030
Fiscal Year Maturities of Long-term Debt
Debt Instrument, Face Amount			$ 100
Minimum \| Note Payable, 1.00% \| Subsidiaries
Debt Instrument
Stated interest rate	1%
Maximum [Member] \| Note Payable, Three Point Two Five Percent \| Subsidiaries
Debt Instrument
Stated interest rate	3.25%

Subordinated Debentures Held _2

Subordinated Debentures Held by Subsidiary Trusts (Details) $ in Millions		1 Months Ended	12 Months Ended
	Aug. 16, 2018	Dec. 31, 2007	Dec. 31, 2022 USD ($) trusts	Dec. 31, 2011	Dec. 31, 2021 USD ($)	May 31, 2020	Nov. 30, 2007
Subordinated Borrowing
Number of company sponsored wholly-owned business trusts \| trusts			14
Subordinated debentures held by subsidiary trusts					$ 87
Stated interest rate						5.25%
Subordinated Debt			$ 163.7		87.7
Subordinated Long-term Debt, Noncurrent			163.1		87
Common Stock Held in Assets			5.3		2.7
Subordinated Debt Fair Value Adjustment			(0.6)		(0.7)
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust II
Subordinated Borrowing
Subordinated Debt			2
Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I
Subordinated Borrowing
Subordinated Debt			5
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust VI
Subordinated Borrowing
Subordinated Debt			30
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust IV
Subordinated Borrowing
Subordinated Debt			22.4
Junior Subordinated Deferrable Interest Debentures Issued by HFFC III
Subordinated Borrowing
Subordinated Debt			5
Junior Subordinated Deferrable Interest Debentures Issued by HFFC IV
Subordinated Borrowing
Subordinated Debt			7
Junior Subordinated Deferrable Interest Debentures Issued by HFFC V
Subordinated Borrowing
Subordinated Debt			5
Junior Subordinated Deferrable Interest Debentures Issued by HFFC VI
Subordinated Borrowing
Subordinated Debt			2
First Interstate Statutory Trust II \| Junior Subordinated Deferrable Interest Debentures Issued by FIST II
Subordinated Borrowing
Subordinated Debt					10.3
First Interstate Statutory Trust III \| Junior Subordinated Deferrable Interest Debentures Issued by FIST III
Subordinated Borrowing
Subordinated Debt					20.6
First Interstate Statutory Trust IV \| Junior Subordinated Deferrable Interest Debentures Issued by FIST IV
Subordinated Borrowing
Subordinated Debt					15.5
First Interstate Statutory Trust V \| Junior Subordinated Deferrable Interest Debentures Issued by FIST V
Subordinated Borrowing
Subordinated Debt					10.3
First Interstate Statutory Trust VI \| Junior Subordinated Deferrable Interest Debentures Issued by FIST VI
Subordinated Borrowing
Subordinated Debt					10.3
Northwest Bancorporation Capital Trust 1 [Member] \| Junior Subordinated Deferrable Interest Debentures Issued by FIST VI
Subordinated Borrowing
Subordinated Debt					5.2
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust II
Subordinated Borrowing
Common Stock Held in Assets			0.1		0
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust II \| Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust II
Subordinated Borrowing
Subordinated Debt			$ 2.1		0
Debt instrument, basis spread on variable rate				1.85%
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust II \| Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust II \| LIBOR
Subordinated Borrowing
Debt instrument, interest rate at period end			6.62%
Junior Subordinated Deferrable Interest Debentures Issued by FIST II
Subordinated Borrowing
Common Stock Held in Assets			$ 0.3		0.3
Junior Subordinated Deferrable Interest Debentures Issued by FIST II \| Junior Subordinated Deferrable Interest Debentures Issued by FIST II
Subordinated Borrowing
Subordinated Debt			$ 10.3
Junior Subordinated Deferrable Interest Debentures Issued by FIST II \| Junior Subordinated Deferrable Interest Debentures Issued by FIST II \| Debt Instrument, Redemption, After Period Five
Subordinated Borrowing
Debt instrument, basis spread on variable rate		2.25%
Junior Subordinated Deferrable Interest Debentures Issued by FIST II \| Junior Subordinated Deferrable Interest Debentures Issued by FIST II \| LIBOR
Subordinated Borrowing
Debt instrument, interest rate at period end			5.99%
Junior Subordinated Deferrable Interest Debentures Issued by FIST I
Subordinated Borrowing
Common Stock Held in Assets			$ 0.5		0.5
Junior Subordinated Deferrable Interest Debentures Issued by FIST I \| Junior Subordinated Deferrable Interest Debentures Issued by FIST I
Subordinated Borrowing
Subordinated Debt			$ 15.5		15.5
Junior Subordinated Deferrable Interest Debentures Issued by FIST I \| Junior Subordinated Deferrable Interest Debentures Issued by FIST I \| Debt Instrument, Redemption, After Period Five
Subordinated Borrowing
Debt instrument, basis spread on variable rate		2.75%
Junior Subordinated Deferrable Interest Debentures Issued by FIST I \| Junior Subordinated Deferrable Interest Debentures Issued by FIST I \| Debt Instrument, Redemption, At Issuance through Year Five [Member]
Subordinated Borrowing
Stated interest rate							7.50%
Junior Subordinated Deferrable Interest Debentures Issued by FIST I \| Junior Subordinated Deferrable Interest Debentures Issued by FIST I \| LIBOR
Subordinated Borrowing
Debt instrument, interest rate at period end			7.52%
Junior Subordinated Deferrable Interest Debentures Issued by FIST III
Subordinated Borrowing
Common Stock Held in Assets			$ 0.6		0.6
Junior Subordinated Deferrable Interest Debentures Issued by FIST III \| Junior Subordinated Deferrable Interest Debentures Issued by FIST III
Subordinated Borrowing
Subordinated Debt			$ 20.6
Junior Subordinated Deferrable Interest Debentures Issued by FIST III \| Junior Subordinated Deferrable Interest Debentures Issued by FIST III \| Debt Instrument, Redemption, After Period Five
Subordinated Borrowing
Debt instrument, basis spread on variable rate		2.40%
Junior Subordinated Deferrable Interest Debentures Issued by FIST III \| Junior Subordinated Deferrable Interest Debentures Issued by FIST III \| Debt Instrument, Redemption, At Issuance through Year Five [Member]
Subordinated Borrowing
Stated interest rate		6.88%
Junior Subordinated Deferrable Interest Debentures Issued by FIST III \| Junior Subordinated Deferrable Interest Debentures Issued by FIST III \| LIBOR
Subordinated Borrowing
Debt instrument, interest rate at period end			7.17%
Junior Subordinated Deferrable Interest Debentures Issued by FIST IV
Subordinated Borrowing
Common Stock Held in Assets			$ 0.5		0.5
Junior Subordinated Deferrable Interest Debentures Issued by FIST IV \| Junior Subordinated Deferrable Interest Debentures Issued by FIST IV
Subordinated Borrowing
Debt instrument, interest rate at period end		2.70%
Subordinated Debt			$ 15.5
Junior Subordinated Deferrable Interest Debentures Issued by FIST IV \| Junior Subordinated Deferrable Interest Debentures Issued by FIST IV \| LIBOR
Subordinated Borrowing
Debt instrument, interest rate at period end			6.44%
Junior Subordinated Deferrable Interest Debentures Issued by FIST V
Subordinated Borrowing
Common Stock Held in Assets			$ 0.3		0.3
Junior Subordinated Deferrable Interest Debentures Issued by FIST V \| Junior Subordinated Deferrable Interest Debentures Issued by FIST V
Subordinated Borrowing
Subordinated Debt			$ 10.3
Junior Subordinated Deferrable Interest Debentures Issued by FIST V \| Junior Subordinated Deferrable Interest Debentures Issued by FIST V \| Debt Instrument, Redemption, After Period Five
Subordinated Borrowing
Debt instrument, basis spread on variable rate				2.75%
Junior Subordinated Deferrable Interest Debentures Issued by FIST V \| Junior Subordinated Deferrable Interest Debentures Issued by FIST V \| Debt Instrument, Redemption, At Issuance through Year Five [Member]
Subordinated Borrowing
Stated interest rate		6.78%
Junior Subordinated Deferrable Interest Debentures Issued by FIST V \| Junior Subordinated Deferrable Interest Debentures Issued by FIST V \| LIBOR
Subordinated Borrowing
Debt instrument, interest rate at period end			6.49%
Junior Subordinated Deferrable Interest Debentures Issued by FIST VI
Subordinated Borrowing
Common Stock Held in Assets			$ 0.3		0.3
Junior Subordinated Deferrable Interest Debentures Issued by FIST VI \| Junior Subordinated Deferrable Interest Debentures Issued by FIST VI
Subordinated Borrowing
Subordinated Debt			$ 10.3
Debt instrument, basis spread on variable rate				2.75%
Junior Subordinated Deferrable Interest Debentures Issued by FIST VI \| Junior Subordinated Deferrable Interest Debentures Issued by FIST VI \| LIBOR
Subordinated Borrowing
Debt instrument, interest rate at period end			6.49%
Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I
Subordinated Borrowing
Common Stock Held in Assets			$ 0.2		0.2
Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I \| Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I
Subordinated Borrowing
Subordinated Debt			$ 5.2
Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I \| Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I \| Debt Instrument, Redemption, After Period Five
Subordinated Borrowing
Debt instrument, basis spread on variable rate	1.70%
Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I \| Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I \| Debt Instrument, Redemption, At Issuance through Year Five [Member]
Subordinated Borrowing
Stated interest rate		5.95%
Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I \| Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I \| LIBOR
Subordinated Borrowing
Debt instrument, interest rate at period end			6.43%
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust VI
Subordinated Borrowing
Common Stock Held in Assets			$ 0.9		0
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust VI \| Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust VI
Subordinated Borrowing
Subordinated Debt			$ 30.9		0
Debt instrument, basis spread on variable rate				1.48%
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust VI \| Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust VI \| LIBOR
Subordinated Borrowing
Debt instrument, interest rate at period end			6.25%
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust IV
Subordinated Borrowing
Common Stock Held in Assets			$ 0.7		0
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust IV \| Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust IV
Subordinated Borrowing
Subordinated Debt			$ 23.1		0
Debt instrument, basis spread on variable rate				2.85%
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust IV \| Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust IV \| LIBOR
Subordinated Borrowing
Debt instrument, interest rate at period end			7.59%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC III
Subordinated Borrowing
Common Stock Held in Assets			$ 0.2		0
Junior Subordinated Deferrable Interest Debentures Issued by HFFC III \| Junior Subordinated Deferrable Interest Debentures Issued by HFFC III
Subordinated Borrowing
Subordinated Debt			$ 5.2		0
Debt instrument, basis spread on variable rate				3.35%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC III \| Junior Subordinated Deferrable Interest Debentures Issued by HFFC III \| LIBOR
Subordinated Borrowing
Debt instrument, interest rate at period end			7.43%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC IV
Subordinated Borrowing
Common Stock Held in Assets			$ 0.2		0
Junior Subordinated Deferrable Interest Debentures Issued by HFFC IV \| Junior Subordinated Deferrable Interest Debentures Issued by HFFC IV
Subordinated Borrowing
Subordinated Debt			$ 7.2		0
Debt instrument, basis spread on variable rate				3.10%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC IV \| Junior Subordinated Deferrable Interest Debentures Issued by HFFC IV \| LIBOR
Subordinated Borrowing
Debt instrument, interest rate at period end			7.18%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC V
Subordinated Borrowing
Common Stock Held in Assets			$ 0.3		0
Junior Subordinated Deferrable Interest Debentures Issued by HFFC V \| Junior Subordinated Deferrable Interest Debentures Issued by HFFC V
Subordinated Borrowing
Subordinated Debt			$ 5.3		0
Debt instrument, basis spread on variable rate				1.83%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC V \| Junior Subordinated Deferrable Interest Debentures Issued by HFFC V \| LIBOR
Subordinated Borrowing
Debt instrument, interest rate at period end			6.59%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC VI
Subordinated Borrowing
Common Stock Held in Assets			$ 0.2		0
Junior Subordinated Deferrable Interest Debentures Issued by HFFC VI \| Junior Subordinated Deferrable Interest Debentures Issued by HFFC VI
Subordinated Borrowing
Subordinated Debt			$ 2.2		$ 0
Debt instrument, basis spread on variable rate				1.65%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC VI \| Junior Subordinated Deferrable Interest Debentures Issued by HFFC VI \| LIBOR
Subordinated Borrowing
Debt instrument, interest rate at period end			5.39%
Trust Preferred Securities Subject to Mandatory Redemption \| Trusts
Subordinated Borrowing
Business trust term (in years)			30 years
Common Stock Subject to Mandatory Redemption \| Trusts
Subordinated Borrowing
Amount of financial instruments subject to mandatory redemption			$ 5.3
Subordinated Debentures Subject to Mandatory Redemption \| Trusts
Subordinated Borrowing
Business trust term (in years)			30 years

Capital Stock and Dividend Re_2

Capital Stock and Dividend Restrictions - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Feb. 01, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	May 25, 2022	Dec. 14, 2021	Jun. 11, 2019
Class of Stock
Common stock, shares authorized		250,000,000	100,000,000
Common stock, shares, outstanding		104,442,023	62,200,456
Stock compensation expense		$ 9.6	$ 8.9	$ 7.5
Aggregate purchase price of shares repurchased and retired		$ 199	$ 5.4	$ 116.8
Stock Repurchased and Retired During Period, Shares		5,040,896	128,171	3,578,743
Sale of Stock Shares Authorized For Future Sale						47,158,390
Accelerated Share Repurchases, Adjustment to Recorded Amount		$ 197.4
Treasury Stock Acquired, Average Cost Per Share		$ 39.48
Great Western Bank
Class of Stock
Total consideration paid	$ 1,723.3
Class A Common Stock
Class of Stock
Stock Repurchased and Retired During Period, Shares		5,000,000
Class A Common Stock
Class of Stock
Common stock, shares authorized		150,000,000
Common Stock, Voting Rights, Votes Per Share		$ 1
Common stock, shares, outstanding			41,699,409
Stock Repurchase Program, Number of Shares Authorized to be Repurchased							5,000,000
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased					1,889,158
Class A Common Stock \| Great Western Bank
Class of Stock
Common stock issued (in shares)	46,879,601
Class B Common Stock
Class of Stock
Common stock, shares authorized		100,000,000
Common stock, shares, outstanding		0	20,501,047
Director [Member] \| Class A Common Stock
Class of Stock
Shares issued to directors during period		33,769
Stock compensation expense		$ 1.3
Board of Directors
Class of Stock
Aggregate value of shares issued to directors			$ 0.9
Board of Directors \| Class A Common Stock
Class of Stock
Shares issued to directors during period			19,081

Earnings per Common Share Compu

Earnings per Common Share Computation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2022	Sep. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net Income (Loss) Available to Common Stockholders, Basic [Abstract]
Net income, basic and diluted			$ 202.2	$ 192.1	$ 161.2
Weighted Average Number of Shares Outstanding, Basic and Diluted [Abstract]
Weighted average common shares outstanding for basic earnings per share computation			103,274,070	61,650,312	63,611,891
Dilutive effect of stock-based compensation (in shares)			66,929	91,516	117,579
Weighted average common shares outstanding for diluted earnings per common share computation			103,340,999	61,741,828	63,729,470
Earnings Per Share, Basic and Diluted [Abstract]
Basic earnings per common share (in dollars per share)			$ 1.96	$ 3.12	$ 2.53
Diluted earnings per common share (in dollars per share)			$ 1.96	$ 3.11	$ 2.53
Restricted Stock [Member]
Earnings Per Share, Basic and Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share (in shares)		83,952	52,027		291,540
Performance Shares
Earnings Per Share, Basic and Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share (in shares)	333,767		470,622		3,094

Regulatory Capital - Schedule o

Regulatory Capital - Schedule of Actual Capital Amounts and Ratios and Selected Minimum Regulatory Thresholds (Details) $ in Millions	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Total risk-based capital:
Actual amount	$ 2,875.8	$ 1,659.3
Capital to Risk Weighted Assets	0.1248	0.1411
Adequately capitalized Basel III phase-in schedule, amount	$ 1,843.2	$ 940.9
Adequately capitalized Basel III phase-in schedule, ratio (percent)	0.0800	0.0800
Adequately capitalized Basel III fully phased-in, amount	$ 2,419.2	$ 1,235
Capital Required For Capital Adequacy Under Basel III Fully Phased-In To Risk Weighted Assets	10.50%	10.50%
Well capitalized, amount	$ 2,304	$ 1,176.2
Capital Required to be Well Capitalized to Risk Weighted Assets	0.1000	0.1000
Tier 1 risk-based capital:
Actual amount	$ 2,408.8	$ 1,469
Tier One Risk Based Capital to Risk Weighted Assets	0.1045	0.1249
Adequately capitalized Basel III phase-in schedule, amount	$ 1,382.4	$ 705.7
Adequately capitalized Basel III phase-in schedule, ratio (percent)	0.0600	0.0600
Adequately capitalized Basel III fully phased-in, amount	$ 1,958.4	$ 999.7
Tier One Capital Required For Capital Adequacy Under Basel III Fully Phased-In To Risk Weighted Assets	8.50%	8.50%
Well capitalized, amount	$ 1,843.2	$ 940.9
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	0.0800	0.0800
Common Equity Tier One Capital [Abstract]
Actual amount	$ 2,408.8	$ 1,384.8
Common Equity Tier One Risk Based Capital To Risk Weighted Assets	10.45%	11.77%
Adequately capitalized Basel III phase-in schedule, amount	$ 1,036.8	$ 529.3
Adequately capitalized Basel III phase-in schedule, ratio (percent)	4.50%	4.50%
Adequately capitalized Basel III fully phased-in, amount	$ 1,612.8	$ 823.3
Tier One Common Equity Capital Required For Capital Adequacy Under Basel III Fully Phased-In To Risk Weighted Assets	7%	7%
Well capitalized, amount	$ 1,497.6	$ 764.5
Common Equity Tier One Capital To Be Well Capitalized To Risk Weighted Assets	6.50%	6.50%
Leverage capital ratio:
Actual amount	$ 2,408.8	$ 1,469
Tier One Leverage Capital to Average Assets	0.0775	0.0768
Adequately capitalized, amount	$ 1,242.9	$ 765.5
Adequately capitalized, ratio (percent)	0.0400	0.0400
Well capitalized, amount	$ 1,553.6	$ 956.9
Well capitalized, ratio (percent)	0.0500	0.0500
FIB
Total risk-based capital:
Actual amount	$ 2,713.5	$ 1,472.5
Capital to Risk Weighted Assets	0.1180	0.1256
Adequately capitalized Basel III phase-in schedule, amount	$ 1,839.6	$ 938
Adequately capitalized Basel III phase-in schedule, ratio (percent)	0.0800	0.0800
Adequately capitalized Basel III fully phased-in, amount	$ 2,414.5	$ 1,231.1
Capital Required For Capital Adequacy Under Basel III Fully Phased-In To Risk Weighted Assets	10.50%	10.50%
Well capitalized, amount	$ 2,299.5	$ 1,172.5
Capital Required to be Well Capitalized to Risk Weighted Assets	0.1000	0.1000
Tier 1 risk-based capital:
Actual amount	$ 2,504.1	$ 1,382.2
Tier One Risk Based Capital to Risk Weighted Assets	0.1089	0.1179
Adequately capitalized Basel III phase-in schedule, amount	$ 1,379.7	$ 703.5
Adequately capitalized Basel III phase-in schedule, ratio (percent)	0.0600	0.0600
Adequately capitalized Basel III fully phased-in, amount	$ 1,954.6	$ 996.6
Tier One Capital Required For Capital Adequacy Under Basel III Fully Phased-In To Risk Weighted Assets	8.50%	8.50%
Well capitalized, amount	$ 1,839.6	$ 938
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	0.0800	0.0800
Common Equity Tier One Capital [Abstract]
Actual amount	$ 2,504.1	$ 1,382.2
Common Equity Tier One Risk Based Capital To Risk Weighted Assets	10.89%	11.79%
Adequately capitalized Basel III phase-in schedule, amount	$ 1,034.8	$ 527.6
Adequately capitalized Basel III phase-in schedule, ratio (percent)	4.50%	4.50%
Adequately capitalized Basel III fully phased-in, amount	$ 1,609.7	$ 820.8
Tier One Common Equity Capital Required For Capital Adequacy Under Basel III Fully Phased-In To Risk Weighted Assets	7%	7%
Well capitalized, amount	$ 1,494.7	$ 762.1
Common Equity Tier One Capital To Be Well Capitalized To Risk Weighted Assets	6.50%	6.50%
Leverage capital ratio:
Actual amount	$ 2,504.1	$ 1,382.2
Tier One Leverage Capital to Average Assets	0.0807	0.0724
Adequately capitalized, amount	$ 1,241.1	$ 764.1
Adequately capitalized, ratio (percent)	0.0400	0.0400
Well capitalized, amount	$ 1,551.4	$ 955.1
Well capitalized, ratio (percent)	0.0500	0.0500

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Unrecorded Unconditional Purchase Obligation
Operating leases, rent expense			$ 5.1
Operating Lease, Expense	$ 8.9	$ 4.3
Assets	32,287.8	19,671.9
Construction Contracts
Unrecorded Unconditional Purchase Obligation
Commitments under construction contracts	$ 1.8
Related Entity
Unrecorded Unconditional Purchase Obligation
Ownership percentage in partnership	50%
Mortgage loans originated for sale
Unrecorded Unconditional Purchase Obligation
Guarantor Obligations, Current Carrying Value	$ 0.9	$ 0.4

Commitments and Contingencies_2

Commitments and Contingencies - Operating Lease Commitments (Details) $ in Millions	Dec. 31, 2022 USD ($)
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	$ 53.9
Commitments
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	48.7
Related Entity
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	5.2
Payments due within year one
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	11.5
Payments due within year one \| Commitments
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	10.1
Payments due within year one \| Related Entity
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	1.4
Payments due year 2
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	10.5
Payments due year 2 \| Commitments
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	9.1
Payments due year 2 \| Related Entity
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	1.4
Payments due year 3
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	9.1
Payments due year 3 \| Commitments
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	7.7
Payments due year 3 \| Related Entity
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	1.4
Payments due year 4
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	7.4
Payments due year 4 \| Commitments
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	6.5
Payments due year 4 \| Related Entity
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	0.9
Payments due year 5
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	4.8
Payments due year 5 \| Commitments
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	4.7
Payments due year 5 \| Related Entity
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	0.1
Payments due after year 5
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	10.6
Payments due after year 5 \| Commitments
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	10.6
Payments due after year 5 \| Related Entity
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	$ 0

Financial Instruments with Of_2

Financial Instruments with Off-Balance Sheet Risk (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Entity Information
Unused credit card lines		$ 2,539.8
Off-Balance Sheet, Credit Loss, Liability	$ 16.2	3.8	$ 3.7
Off-Balance Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal)	(68.4)	14.7	$ (55.5)
Cumulative Effect, Period of Adoption, Adjusted Balance
Entity Information
Off-Balance Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal)	12.4	0.1
Unused Credit Card Lines
Entity Information
Credit extension commitments	827.6	681.6
Unused credit card lines	5,173.3
Standby Letters of Credit
Entity Information
Credit extension commitments	$ 93.8	$ 57.5

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Current:
Federal	$ 45.2	$ 39.4	$ 42.4
State	14.4	11.3	12.3
Total current	59.6	50.7	54.7
Deferred:
Federal	(3.7)	3.7	(5.7)
State	(1)	1.3	(0.9)
Total deferred	(4.7)	5	(6.6)
Total income tax expense	54.9	55.7	48.1
Operating Loss Carryforwards [Line Items]
Deficiency (benefit) of stock-based compensation plans	0.2	(0.5)	(0.4)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount	$ 2	$ 0.8	$ 0

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Tax Expense at Effective Tax Rate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Expense, Continuing Operations Income Tax Reconciliation [Abstract]
Tax expense at the statutory tax rate	$ 54	$ 52	$ 44
Increase (decrease) in tax resulting from:
Tax-exempt income	(8.4)	(2.8)	(2.1)
State income tax, net of federal income tax benefit	10.6	9.9	9
Deficiency (benefit) of stock-based compensation plans	0.2	(0.5)	(0.4)
Federal tax credits	(4.3)	(4.3)	(2.3)
Other, net	0.8	0.6	(0.1)
Total income tax expense	$ 54.9	$ 55.7	$ 48.1

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Loans, principally due to allowance for credit losses	$ 54.8	$ 30.7
Loan discount	32.5	1.6
Investment securities, unrealized losses	157.9	4.6
Deferred compensation	26.8	19.3
Non-performing loan interest	2.6	1
Net operating loss carryforwards	1.5	1.7
Lease liabilities	12	8.7
Other	2.4	3.5
Deferred tax assets	323.2	71.1
Deferred tax liabilities:
Fixed assets, principally differences in bases and depreciation	(17.3)	(7.7)
Deferred loan costs	(3.3)	(1.9)
Deferred Tax Liabilities, Derivatives	0	1
Investment in joint venture partnership, principally due to differences in depreciation of partnership assets	(1.3)	(0.9)
Right of use assets	(11.3)	(8.3)
Prepaid amounts	(0.9)	(0.7)
Government agency stock dividends	(1.2)	(1.2)
Goodwill and other intangibles	(68.2)	(51.2)
Mortgage servicing rights	(7.4)	(6.8)
Other	(1.8)	(0.7)
Deferred tax liabilities	(112.7)	(80.4)
Deferred Tax Liabilities, Net	210.5	9.3
Operating Loss Carryforwards [Line Items]
Deferred Income Tax Expense (Benefit)	(4.7)	5	$ (6.6)
Tax Credit Carryforward, Amount	2.7
Other real estate owned write-downs and carrying costs	1.5	0
Deferred Tax Assets, Derivative Instruments	0.5	0
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Reserves	8.8	0
Deferred Tax Assets, Contract Incentives	8.5	0
Deferred Tax Assets, Discount on Acquired Investment Securities	$ 13.4	$ 0

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Current net income tax receivable	$ 38.3	$ 16.1

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options expiration period	10 years
Intrinsic value of fully-vested stock options outstanding	$ 0
Share-based Payment Arrangement, Exercise of Option, Tax Benefit	0.1	$ 0.2	$ 0.5
Stock compensation expense	9.6	8.9	7.5
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of options exercised	0.6	1.5	3.1
Proceeds from Stock Options Exercised	0.1	0.5	1.1
Common Stock Redeemed For Payment of Stock Option Exercises, Aggregate Value	$ 0.2	0.3	1
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	1 year 2 months 26 days
Tax benefits from stock-based compensation	$ (0.3)	(0.3)	(0.1)
Stock issued during period, shares, restricted stock award	458,176			(27,247)
Unrecognized compensation cost related to nonvested restricted stock awards	$ 15.8
Stock compensation expense	$ 9.6	$ 8.9	$ 7.5
Restricted Stock [Member] \| Upon Achievement of Performance Goals
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	263,582
Restricted Stock [Member] \| Upon Achievement of Defined Return on Equity Performance Goals
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	131,791
Restricted Stock [Member] \| Upon Achievement of Defined Total Return to Shareholder Goals
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	131,791
Restricted Stock [Member] \| Time-restricted shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	221,841
Restricted Stock [Member] \| One Year from Grant Date
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	38,845
Restricted Stock [Member] \| Upon One-Third Annual Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	182,996
2006 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant	361,605

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock Options Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	0 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	0 years
Intrinsic value of fully-vested stock options outstanding	$ 0
Share-based Payment Arrangement, Exercise of Option, Tax Benefit	$ 0.1	$ 0.2	$ 0.5
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	0	23,252
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 0	$ 14.37
Vested, number of shares	(22,684)
Exercised, weighted average exercise price (in dollars per share)	$ 14.37
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	568
Forfeited, weighted average exercise price (in dollars per share)	$ 14.37
Outstanding options exercisable, end of year, number of shares	0
Outstanding options exercisable, end of year, weighted average exercise price (in dollars per share)	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding options, beginning of year, number of shares	23,252
Forfeited, number of shares	(568)
Outstanding options, end of year, number of shares	0	23,252
Outstanding options exercisable, end of year, number of shares	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding options, beginning of year, weighted average exercise price (in dollars per share)	$ 14.37
Exercised, weighted average exercise price (in dollars per share)	14.37
Forfeited, weighted average exercise price (in dollars per share)	14.37
Outstanding options, end of year, weighted average exercise price (in dollars per share)	0	$ 14.37
Outstanding options exercisable, end of year, weighted average exercise price (in dollars per share)	$ 0
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of options exercised	$ 0.6	$ 1.5	3.1
Proceeds from Stock Options Exercised	0.1	0.5	1.1
Common Stock Redeemed For Payment of Stock Option Exercises, Aggregate Value	$ 0.2	$ 0.3	$ 1

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of Restricted Stock Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	$ 9.6	$ 8.9	$ 7.5
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Vested, number of shares	(22,684)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Ending Balance	$ 3,073.8	1,986.6	1,959.8	$ 2,013.9
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	458,176			(27,247)
Stock compensation expense	$ 9.6	$ 8.9	7.5
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock, beginning of year, number of shares	521,012
Granted, number of shares	458,176
Vested, number of shares	(131,199)
Forfeited, number of shares	(106,891)
Restricted stock, end of year, number of shares	741,098	521,012
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Restricted stock, beginning of year, weighted-average measurement date fair value (in dollars per share)	$ 39.73
Granted, weighted average grant date fair value (in dollars per share)		$ 38.67
Vested, weighted average grant date fair value (in dollars per share)		39.92
Forfeited, weighted average grant date fair value (in dollars per share)		38.61
Restricted stock, end of year, weighted-average measurement date fair value (in dollars per share)	$ 38.94	$ 39.73
Tax benefits from stock-based compensation	$ (0.3)	$ (0.3)	(0.1)
Unrecognized compensation cost related to nonvested restricted stock awards	$ 15.8
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	1 year 2 months 26 days
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	$ 9.6	8.9	7.5
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Ending Balance	$ 2,478.2	$ 945	$ 941.1	$ 1,049.3
Upon Achievement of Defined Total Return to Shareholder Goals \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	131,791
Upon One-Third Annual Anniversary \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	182,996
Upon Achievement of Performance Goals \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	263,582
Upon Achievement of Defined Return on Equity Performance Goals \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	131,791
One Year from Grant Date \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	38,845
Time-restricted shares \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	221,841

Employee Benefit Plans - Profit

Employee Benefit Plans - Profit Sharing and Savings Plans (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits
Other Comprehensive Income (Loss), Tax	$ (155,200,000)	$ (155,200,000)	$ (22,800,000)	$ 15,600,000
Savings Plan, Employee Elected
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits
Compensation expense		13,500,000	$ 8,800,000	$ 8,900,000
Maximum annual contribution per employee, amount per dollar of employee contribution		0.06
Savings Plan, Company Elected
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits
Maximum annual contribution per employee, amount per dollar of employee contribution		$ 1

Other Comprehensive Income - Sc

Other Comprehensive Income - Schedule of Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Equity [Abstract]
Other comprehensive (loss) income, before tax	$ (621.3)	$ (621.3)	$ (90.4)	$ 61.2
Other Comprehensive Income (Loss), Tax	(155.2)	(155.2)	(22.8)	15.6
Other Comprehensive Income (Loss), Net of Tax	$ (466.1)		(67.6)	45.6
Before Tax Amount
Change in net unrealized loss during period		(613.1)	(113.7)	61.8
Reclassification adjustment for net gains included in net income		24.4	(1.1)	(0.3)
Reclassification adjustment for securities transferred from held-to-maturity to available-for-sale		0.2	0	0
OCI, Debt Securities, Available-for-Sale, Transfer to Held-to-Maturity, Adjustment from AOCI for Amortization of Gain (Loss), before Tax		(26.1)	20.2	0
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		(4.9)	3.1	0.2
OCI, Debt Securities, Available-for-Sale, Gain (Loss), before Adjustment, Tax		(6.7)	4.2	0.2
Change in net actuarial gains				(0.5)
Tax Expense (Benefit)
Change in net unrealized loss during period		(152.4)	(28.7)	15.8
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Tax		0.1
OCI, Debt Securities, Available-for-Sale, Transfer to Held-to-Maturity, Adjustment from AOCI for Amortization of Gain (Loss), Tax		(6.6)	5.1
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax		1.8	(1.1)	0
Reclassification adjustment for net gains included in net income		5.5	(0.3)	(0.1)
Change in net actuarial gains				(0.1)
Net of Tax Amount
Change in net unrealized gains during period		(460.7)	(85)	46
Reclassification adjustment for net gains included in net income		18.9	(0.8)	(0.2)
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Net of Tax		0.1
OCI, Debt Securities, Available-for-Sale, Transfer to Held-to-Maturity, Adjustment from AOCI for Amortization of Gain (Loss), after Tax		19.5	(15.1)
Change in net actuarial gains				(0.4)
Unrealized Gain (Loss) on Derivatives		(1.6)	3
Stockholders' Equity Attributable to Parent		3,073.8	1,986.6	$ 1,959.8	$ 2,013.9
Debt Securities, Held-to-maturity, Transfer, Unrealized Gain (Loss)		$ (4.5)	$ 15

Other Comprehensive Income - Ac

Other Comprehensive Income - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Change in net unrealized loss during period	$ (613.1)	$ (113.7)	$ 61.8
Reclassification adjustment for net gains included in net income	24.4	(1.1)	(0.3)
Accumulated other comprehensive income (loss)	3,073.8	1,986.6	$ 1,959.8	$ 2,013.9
Net unrealized loss on investment securities available-for-sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss)	$ (471)	$ (29)

Condensed Financial Informati_3

Condensed Financial Information (Parent Company Only) - Condensed Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed balance sheets:
Cash and cash equivalents	$ 870.5	$ 2,344.8
Investment in subsidiaries, at equity:
Other assets	348.7	184.1
Total assets	32,287.8	19,671.9
Long-term debt	98.9	98.7
Subordinated debentures held by subsidiary trusts		87
Total liabilities	29,214	17,685.3
Stockholders’ equity	3,073.8	1,986.6	$ 1,959.8	$ 2,013.9
Total liabilities and stockholders’ equity	32,287.8	19,671.9
Parent Company
Condensed balance sheets:
Cash and cash equivalents	154.8	181.1
Investment in subsidiaries, at equity:
Equity method investments	2,985.8	1,948.9
Advances from subsidiaries, net	0.1	5.9
Other assets	240.7	63.2
Total assets	3,381.4	2,199.1
Other liabilities	45.6	26.8
Subordinated debentures held by subsidiary trusts	163.1	87
Total liabilities	307.6	212.5
Stockholders’ equity	3,073.8	1,986.6
Total liabilities and stockholders’ equity	$ 3,381.4	$ 2,199.1

Condensed Financial Informati_4

Condensed Financial Information (Parent Company Only) - Condensed Statements of Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Condensed Financial Statements, Captions
Salaries and benefits	$ 282.1	$ 164.9	$ 173.7
Interest expense	78.9	17.3	26.6
Acquisition related expenses	118.9	11.6	0
Earnings before income tax benefit	257.1	247.8	209.3
Income tax benefit	54.9	55.7	48.1
Net income	202.2	192.1	161.2
Parent Company
Condensed Financial Statements, Captions
Dividends from subsidiaries	360	160	130
Other interest income	0.4	0	0.1
Other income, primarily management fees from subsidiaries	51.7	41.3	28.7
Total income	412.1	201.3	158.8
Salaries and benefits	40.6	36.4	31.5
Interest expense	12.6	8.2	6.6
Acquisition related expenses	62.3	11.6	0
Other operating expenses, net	25	17.6	15.6
Total expenses	140.5	73.8	53.7
Earnings before income tax benefit	271.6	127.5	105.1
Income tax benefit	(18.9)	(7.6)	(6.1)
Income before undistributed earnings of subsidiaries	290.5	135.1	111.2
Undistributed (loss) earnings of subsidiaries	(88.3)	57	50
Net income	$ 202.2	$ 192.1	$ 161.2

Condensed Financial Informati_5

Condensed Financial Information (Parent Company Only) - Condensed Statements of Cash Flows (Details) - USD ($) $ in Millions		12 Months Ended
	Feb. 01, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income		$ 202.2	$ 192.1	$ 161.2
Adjustments to reconcile net income to cash provided by operating activities:
Stock-based compensation expense		9.6	8.9	7.5
Net cash provided by operating activities		534.4	282.3	268.3
Cash flows from investing activities:
Net cash used in investing activities		(949)	(2,120)	(1,869.8)
Cash flows from financing activities:
Proceeds from issuance of common stock, net of stock issuance costs		0.1	0.4	1.1
Purchase and retirement of common stock		(199)	(5.4)	(116.8)
Dividends paid to common stockholders		(182.1)	(101.6)	(128.6)
Net cash used in financing activities		(1,059.7)	1,905.7	2,801.5
Net (decrease) increase in cash and cash equivalents		(1,474.3)	68	1,200
Cash and cash equivalents at beginning of period		2,344.8	2,276.8	1,076.8
Cash and cash equivalents at end of period		870.5	2,344.8	2,276.8
Parent Company
Cash flows from operating activities:
Net income		202.2	192.1	161.2
Adjustments to reconcile net income to cash provided by operating activities:
Undistributed earnings of subsidiaries		88.3	(57)	(50)
Stock-based compensation expense		9.6	8.9	7.5
Other, net		(151.2)	(3.2)	(13.6)
Net cash provided by operating activities		148.9	140.8	105.1
Cash flows from investing activities:
Acquisition of bank and bank holding company, net of cash and cash equivalents received		(0.8)	0	0
Net cash used in investing activities		(0.8)	0	0
Cash flows from financing activities:
Net increase in advances from subsidiaries		206.5	23.7	16.7
Proceeds from issuance of long-term debt		0	0	98.6
Proceeds from issuance of common stock, net of stock issuance costs		0.1	0.4	1.1
Purchase and retirement of common stock		(198.9)	(5.4)	(116.8)
Dividends paid to common stockholders		(182.1)	(101.6)	(128.6)
Net cash used in financing activities		(174.4)	(82.9)	(129)
Net (decrease) increase in cash and cash equivalents		(26.3)	57.9	(23.9)
Cash and cash equivalents at beginning of period		181.1	123.2	147.1
Cash and cash equivalents at end of period		$ 154.8	$ 181.1	$ 123.2
Great Western Bank
Cash flows from financing activities:
Stock Issued	$ 1,722.5

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on a Recurring and Non-Recurring Basis (Details) $ in Millions	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	$ 6,946.1	$ 4,820.5
Derivative assets	45.2	28.1
Derivative liabilities	159.6	18.2
Deferred compensation plan assets	18.7	21.4
Deferred compensation plan liabilities	18.7	21.4
Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0	0
Deferred compensation plan assets	0	0
Deferred compensation plan liabilities	0	0
Significant Other Observable Inputs (Level 2) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	79.9	30.1
Deferred compensation plan assets	18.7	21.4
Deferred compensation plan liabilities	18.7	21.4
Significant Unobservable Inputs (Level 3) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0	0
Deferred compensation plan assets	0	0
Deferred compensation plan liabilities	0	0
Loans And Leases Receivable, Other Real Estate Owned [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	0	0
Loans And Leases Receivable, Other Real Estate Owned [Member] \| Significant Other Observable Inputs (Level 2) \| Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	0	0
Loans And Leases Receivable, Other Real Estate Owned [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	12.7	2
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	642.7	684.7
US Treasury Securities [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	684.7
US Treasury Securities [Member] \| Significant Other Observable Inputs (Level 2) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	642.7	0
US Treasury Securities [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
State, county and municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	263.7	427.5
State, county and municipal securities \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
State, county and municipal securities \| Significant Other Observable Inputs (Level 2) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	263.7	427.5
State, county and municipal securities \| Significant Unobservable Inputs (Level 3) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
US Government Agencies Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	198.9	346.9
US Government Agencies Debt Securities [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
US Government Agencies Debt Securities [Member] \| Significant Other Observable Inputs (Level 2) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	198.9	346.9
US Government Agencies Debt Securities [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	4,259.7	2,018.1
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Significant Other Observable Inputs (Level 2) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	4,259.7	2,018.1
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	228	173.4
Mortgage-backed Securities, Issued by Private Enterprises [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Mortgage-backed Securities, Issued by Private Enterprises [Member] \| Significant Other Observable Inputs (Level 2) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	228	173.4
Mortgage-backed Securities, Issued by Private Enterprises [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	241.5	270.5
Corporate securities \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Corporate securities \| Significant Other Observable Inputs (Level 2) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	241.5	270.5
Corporate securities \| Significant Unobservable Inputs (Level 3) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Collateralized Loan Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,111.6	899.4
Collateralized Loan Obligations \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Collateralized Loan Obligations \| Significant Other Observable Inputs (Level 2) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,111.6	899.4
Collateralized Loan Obligations \| Significant Unobservable Inputs (Level 3) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Estimated Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	6,946.1	4,820.5
Derivative assets	45.2	28.1
Derivative liabilities	159.6	18.2
Deferred compensation plan assets	18.7	21.4
Deferred compensation plan liabilities	18.7	21.4
Estimated Fair Value \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	79.9	30.1
Deferred compensation plan assets	18.7	21.4
Deferred compensation plan liabilities	18.7	21.4
Estimated Fair Value \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	684.7
Derivative assets	0	0
Derivative liabilities	0	0
Deferred compensation plan assets	0	0
Deferred compensation plan liabilities	0	0
Estimated Fair Value \| Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	6,946.1	4,135.8
Derivative assets	45.2	28.1
Derivative liabilities	159.6	18.2
Deferred compensation plan assets	18.7	21.4
Deferred compensation plan liabilities	18.7	21.4
Estimated Fair Value \| Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Derivative assets	0	0
Derivative liabilities	0	0
Deferred compensation plan assets	0	0
Deferred compensation plan liabilities	0	0
Estimated Fair Value \| Loans And Leases Receivable, Other Real Estate Owned [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	12.7	2
Estimated Fair Value \| US Treasury Securities [Member] \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	642.7	684.7
Estimated Fair Value \| State, county and municipal securities \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	263.7	427.5
Estimated Fair Value \| US Government Agencies Debt Securities [Member] \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	198.9	346.9
Estimated Fair Value \| Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	4,259.7	2,018.1
Estimated Fair Value \| Mortgage-backed Securities, Issued by Private Enterprises [Member] \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	228	173.4
Estimated Fair Value \| Corporate securities \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	241.5	270.5
Estimated Fair Value \| Collateralized Loan Obligations \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,111.6	899.4
Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	45.1	26.3
Derivative liabilities	159.6	18.2
Interest Rate Swap \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Interest Rate Swap \| Significant Other Observable Inputs (Level 2) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	45.1	26.3
Derivative liabilities	154.2	18.2
Interest Rate Swap \| Significant Unobservable Inputs (Level 3) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Interest Rate Swap \| Estimated Fair Value \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	45.1	26.3
Derivative liabilities	154.2	18.2
Interest Rate Lock Commitments [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0
Interest Rate Lock Commitments [Member] \| Significant Other Observable Inputs (Level 2) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		1.8
Interest Rate Lock Commitments [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0
Interest Rate Lock Commitments [Member] \| Estimated Fair Value \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		$ 1.8
Forward Contracts [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0
Forward Contracts [Member] \| Significant Other Observable Inputs (Level 2) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0.1
Forward Contracts [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0
Forward Contracts [Member] \| Estimated Fair Value \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0.1
Interest Rate Collars \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0
Interest Rate Collars \| Significant Other Observable Inputs (Level 2) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	5.4
Interest Rate Collars \| Significant Unobservable Inputs (Level 3) \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0
Interest Rate Collars \| Estimated Fair Value \| Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	$ 5.4
Valuation, Market Approach [Member] \| Measurement Input, Discount Rate [Member] \| Maximum [Member] \| Loans And Leases Receivable, Impaired Loans [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing Asset, Measurement Input	0.45
Valuation, Market Approach [Member] \| Measurement Input, Discount Rate [Member] \| Maximum [Member] \| Loans And Leases Receivable, Other Real Estate Owned [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing Asset, Measurement Input	0.36
Valuation, Market Approach [Member] \| Measurement Input, Discount Rate [Member] \| Weighted Average [Member] \| Loans And Leases Receivable, Impaired Loans [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing Asset, Measurement Input	0.07
Valuation, Market Approach [Member] \| Measurement Input, Discount Rate [Member] \| Weighted Average [Member] \| Loans And Leases Receivable, Other Real Estate Owned [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing Asset, Measurement Input	0.22

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Inputs, Quantitative Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2022 USD ($)
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	$ 4,820.5	$ 6,946.1
Minimum \| Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Discount Rate for Level 3 Fair Value Disclosure	(1.00%)
Weighted Average [Member] \| Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Discount Rate for Level 3 Fair Value Disclosure	(7.00%)
Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Collateral-dependent loans	$ 0	0
Other real estate owned	0	0
Long-lived assets to be disposed of by sale	0	(0.2)
Estimated Fair Value
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	4,820.5	6,946.1
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Estimated Fair Value
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	684.7	0
Significant Other Observable Inputs (Level 2) \| Estimated Fair Value
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	4,135.8	6,946.1
Significant Unobservable Inputs (Level 3) \| Estimated Fair Value
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	$ 0	0
Measurement Input, Discount Rate [Member] \| Maximum [Member] \| Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Discount Rate for Level 3 Fair Value Disclosure	(18.00%)
Loans And Leases Receivable, Impaired Loans [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Collateral-dependent loans	$ 0	0
Loans And Leases Receivable, Impaired Loans [Member] \| Significant Other Observable Inputs (Level 2) \| Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Collateral-dependent loans	0	0
Loans And Leases Receivable, Impaired Loans [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Collateral-dependent loans	(11.7)
Loans And Leases Receivable, Impaired Loans [Member] \| Significant Unobservable Inputs (Level 3) \| Estimated Fair Value \| Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Collateral-dependent loans	(11.7)	$ (39.1)
Loans And Leases Receivable, Impaired Loans [Member] \| Measurement Input, Discount Rate [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member] \| Minimum \| Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input		0
Loans And Leases Receivable, Impaired Loans [Member] \| Measurement Input, Discount Rate [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member] \| Maximum [Member] \| Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input		0.45
Loans And Leases Receivable, Impaired Loans [Member] \| Measurement Input, Discount Rate [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member] \| Weighted Average [Member] \| Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input		0.07
Loans And Leases Receivable, Other Real Estate Owned [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other real estate owned	0	$ 0
Loans And Leases Receivable, Other Real Estate Owned [Member] \| Significant Other Observable Inputs (Level 2) \| Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other real estate owned	0	0
Loans And Leases Receivable, Other Real Estate Owned [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other real estate owned	(2)	(12.7)
Loans And Leases Receivable, Other Real Estate Owned [Member] \| Significant Unobservable Inputs (Level 3) \| Estimated Fair Value \| Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other real estate owned	(2)	$ (12.7)
Loans And Leases Receivable, Other Real Estate Owned [Member] \| Measurement Input, Discount Rate [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member] \| Minimum \| Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input		0.15
Loans And Leases Receivable, Other Real Estate Owned [Member] \| Measurement Input, Discount Rate [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member] \| Maximum [Member] \| Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input		0.36
Loans And Leases Receivable, Other Real Estate Owned [Member] \| Measurement Input, Discount Rate [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member] \| Weighted Average [Member] \| Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input		0.22
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Long-lived assets to be disposed of by sale	0	$ 0
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] \| Significant Other Observable Inputs (Level 2) \| Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Long-lived assets to be disposed of by sale	0	0
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Long-lived assets to be disposed of by sale	(1.3)	(5.5)
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] \| Significant Unobservable Inputs (Level 3) \| Estimated Fair Value \| Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Long-lived assets to be disposed of by sale	$ (1.3)	$ (5.5)
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] \| Measurement Input, Discount Rate [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member] \| Minimum \| Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input		0
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] \| Measurement Input, Discount Rate [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member] \| Maximum [Member] \| Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input		0.06
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] \| Measurement Input, Discount Rate [Member] \| Significant Unobservable Inputs (Level 3) \| Fair Value, Nonrecurring [Member] \| Weighted Average [Member] \| Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input		0.03

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - Fair Value, Nonrecurring [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	$ 0	$ 0
Carrying Amount \| Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	39.1	11.7
Assets Held-for-sale, Long Lived, Fair Value Disclosure	$ 5.5	$ 1.3
Long Lived Assets Held-for-sale, Description	5.7 million
Changes Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Held-for-sale, Long Lived, Fair Value Disclosure	$ 0.2

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Estimated Fair Values of Financial Instruments by Level of Valuation Inputs (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Financial assets:
Estimated Fair Value	$ 6,946.1	$ 4,820.5
Held-to-maturity investment securities, estimated fair value	3,052.2	1,667.5
Derivative assets	45.2	28.1
Deferred compensation plan assets	18.7	21.4
Financial liabilities:
Derivative liabilities	159.6	18.2
Deferred compensation plan liabilities	18.7	21.4
Carrying Amount
Financial assets:
Cash and cash equivalents	870.5	2,344.8
Estimated Fair Value	6,946.1	4,820.5
Held-to-maturity investment securities, estimated fair value	3,451.8	1,687.6
Accrued interest receivable	118.3	47.4
Mortgage servicing rights, net	31.1	28.2
Loans Held-for-sale, Fair Value Disclosure	79.9	30.1
Net loans held for investment	17,879.1	9,209.4
Derivative assets	45.2	28.1
Deferred compensation plan assets	18.7	21.4
Total financial assets	29,440.7	18,217.5
Financial liabilities:
Total deposits, excluding time deposits	23,145.2	15,303.1
Time deposits	1,928.4	966.5
Securities sold under repurchase agreements	1,052.9	1,051.1
Federal Home Loan Bank Borrowings, Fair Value Disclosure	2,327
Accrued interest payable	14.5	3.7
Long-term debt	120.8	112.4
Subordinated debentures held by subsidiary trusts	163.1	87
Derivative liabilities	159.6	18.2
Deferred compensation plan liabilities	18.7	21.4
Total financial liabilities	28,930.2	17,563.4
Estimated Fair Value
Financial assets:
Cash and cash equivalents	870.5	2,344.8
Estimated Fair Value	6,946.1	4,820.5
Held-to-maturity investment securities, estimated fair value	3,052.2	1,667.5
Accrued interest receivable	118.3	47.4
Mortgage servicing rights, net	37.4	28.2
Loans Held-for-sale, Fair Value Disclosure	79.9	30.1
Net loans held for investment	17,552.1	9,254.3
Derivative assets	45.2	28.1
Deferred compensation plan assets	18.7	21.4
Total financial assets	28,720.4	18,242.3
Financial liabilities:
Total deposits, excluding time deposits	23,145.2	15,303.1
Time deposits	1,876.1	963.1
Securities sold under repurchase agreements	1,052.9	1,051.1
Federal Home Loan Bank Borrowings, Fair Value Disclosure	2,327
Accrued interest payable	14.5	3.7
Long-term debt	116.3	120.7
Subordinated debentures held by subsidiary trusts	155.8	85.5
Derivative liabilities	159.6	18.2
Deferred compensation plan liabilities	18.7	21.4
Total financial liabilities	28,866.1	17,566.8
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Estimated Fair Value
Financial assets:
Cash and cash equivalents	870.5	2,344.8
Estimated Fair Value	0	684.7
Held-to-maturity investment securities, estimated fair value	0	0
Accrued interest receivable	0	0
Mortgage servicing rights, net	0	0
Loans Held-for-sale, Fair Value Disclosure	0	0
Net loans held for investment	0	0
Derivative assets	0	0
Deferred compensation plan assets	0	0
Total financial assets	870.5	3,029.5
Financial liabilities:
Total deposits, excluding time deposits	23,145.2	15,303.1
Time deposits	0	0
Securities sold under repurchase agreements	0	0
Federal Home Loan Bank Borrowings, Fair Value Disclosure	0
Accrued interest payable	0	0
Long-term debt	0	0
Subordinated debentures held by subsidiary trusts	0	0
Derivative liabilities	0	0
Deferred compensation plan liabilities	0	0
Total financial liabilities	23,145.2	15,303.1
Significant Other Observable Inputs (Level 2) \| Estimated Fair Value
Financial assets:
Cash and cash equivalents	0	0
Estimated Fair Value	6,946.1	4,135.8
Held-to-maturity investment securities, estimated fair value	3,052.2	1,667.5
Accrued interest receivable	118.3	47.4
Mortgage servicing rights, net	37.4	28.2
Loans Held-for-sale, Fair Value Disclosure	79.9	30.1
Net loans held for investment	17,513	9,242.6
Derivative assets	45.2	28.1
Deferred compensation plan assets	18.7	21.4
Total financial assets	27,810.8	15,201.1
Financial liabilities:
Total deposits, excluding time deposits	0	0
Time deposits	1,876.1	963.1
Securities sold under repurchase agreements	1,052.9	1,051.1
Federal Home Loan Bank Borrowings, Fair Value Disclosure	2,327
Accrued interest payable	14.5	3.7
Long-term debt	116.3	120.7
Subordinated debentures held by subsidiary trusts	155.8	85.5
Derivative liabilities	159.6	18.2
Deferred compensation plan liabilities	18.7	21.4
Total financial liabilities	5,720.9	2,263.7
Significant Unobservable Inputs (Level 3) \| Estimated Fair Value
Financial assets:
Cash and cash equivalents	0	0
Estimated Fair Value	0	0
Held-to-maturity investment securities, estimated fair value	0	0
Accrued interest receivable	0	0
Mortgage servicing rights, net	0	0
Loans Held-for-sale, Fair Value Disclosure	0	0
Net loans held for investment	39.1	11.7
Derivative assets	0	0
Deferred compensation plan assets	0	0
Total financial assets	39.1	11.7
Financial liabilities:
Total deposits, excluding time deposits	0	0
Time deposits	0	0
Securities sold under repurchase agreements	0	0
Federal Home Loan Bank Borrowings, Fair Value Disclosure	0
Accrued interest payable	0	0
Long-term debt	0	0
Subordinated debentures held by subsidiary trusts	0	0
Derivative liabilities	0	0
Deferred compensation plan liabilities	0	0
Total financial liabilities	$ 0	$ 0

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Loans and Leases Receivable, Related Parties Disclosure [Abstract]
Loan repayments		$ 700
Amount of loans removed due to changes in related parties	$ 0
Executive Officers, Directors, Shareholders Greater than Five Percent, and Related Entities and Individuals to Such Persons [Member]
Loans and Leases Receivable, Related Parties Disclosure [Abstract]
Loans and leases receivable, related parties	18,900	19,500
New loans and advances on existing loans	6,500
Loan repayments	7,100
Board of Directors Chairman \| Airplane Usage by Company
Loans and Leases Receivable, Related Parties Disclosure [Abstract]
Related party transactions, other revenues	26	61	$ 54
Entity Majority Owned by Shareholders and Directors [Member] \| Education, Communication, Strategic Enterprise Planning and Corporate Governance Consultation [Member]
Loans and Leases Receivable, Related Parties Disclosure [Abstract]
Related party transaction, expenses from transactions with related party	$ 102	$ 87	$ 85

Recent Authoritative Accounting

Recent Authoritative Accounting Guidance (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent	$ 3,073.8	$ 1,986.6	$ 1,959.8	$ 2,013.9
Off-Balance Sheet, Credit Loss, Liability	16.2	3.8	3.7
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent	$ 1,072.7	$ 1,052.6	$ 962.1	$ 953.6

Subsequent Events Subsequent Ev

Subsequent Events Subsequent Events (Details)	Jan. 25, 2023 $ / shares
Class A Common Stock \| Subsequent Event
Subsequent Event [Line Items]
Dividends (in dollars per share)	$ 0.47