The York Water Company (YORW) 10-K10 Mar 202019 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, 2019	Mar. 10, 2020	Jun. 30, 2019
Cover [Abstract]
Entity Registrant Name	YORK WATER CO
Entity Central Index Key	0000108985
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Public Float			$ 463,441,531
Entity Common Stock, Shares Outstanding		13,016,725
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Address, State or Province	PA

Balance Sheets

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
ASSETS
UTILITY PLANT, at original cost	$ 401,383	$ 380,784
Plant acquisition adjustments	(3,318)	(3,108)
Accumulated depreciation	(84,841)	(78,519)
Net utility plant	313,224	299,157
OTHER PHYSICAL PROPERTY, net of accumulated depreciation of $435 in 2019 and $410 in 2018	769	714
CURRENT ASSETS:
Cash and cash equivalents	2	2
Accounts receivable, net of reserves of $305 in 2019 and $305 in 2018	4,421	4,811
Unbilled revenues	2,276	2,427
Recoverable income taxes	547	0
Materials and supplies inventories, at cost	1,007	876
Prepaid expenses	1,131	895
Total current assets	9,384	9,011
OTHER LONG-TERM ASSETS:
Note receivable	255	255
Deferred regulatory assets	34,189	32,353
Other assets	5,708	3,650
Total other long-term assets	40,152	36,258
Total Assets	363,529	345,140
COMMON STOCKHOLDERS' EQUITY:
Common stock, no par value, authorized 46,500,000 shares, issued and outstanding 13,014,898 shares in 2019 and 12,943,536 shares in 2018	83,976	81,305
Retained earnings	50,209	44,890
Total common stockholders' equity	134,185	126,195
PREFERRED STOCK, authorized 500,000 shares, no shares issued	0	0
LONG-TERM DEBT, excluding current portion	94,535	93,328
COMMITMENTS
CURRENT LIABILITIES:
Short-term borrowings	0	1,000
Current portion of long-term debt	6,500	30
Accounts payable	3,452	3,030
Dividends payable	2,096	1,999
Accrued compensation and benefits	1,247	1,191
Accrued income taxes	0	150
Accrued interest	914	992
Deferred regulatory liabilities	609	2,104
Other accrued expenses	338	345
Total current liabilities	15,156	10,841
DEFERRED CREDITS:
Customers' advances for construction	7,844	6,849
Deferred income taxes	40,426	36,962
Deferred employee benefits	4,317	4,715
Deferred regulatory liabilities	24,790	24,710
Other deferred credits	2,247	1,815
Total deferred credits	79,624	75,051
Contributions in aid of construction	40,029	39,725
Total Stockholders' Equity and Liabilities	$ 363,529	$ 345,140

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
ASSETS
Other physical property, accumulated depreciation	$ 435	$ 410
CURRENT ASSETS:
Accounts receivables, reserves	$ 305	$ 305
COMMON STOCKHOLDERS' EQUITY:
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, authorized (in shares)	46,500,000	46,500,000
Common stock, issued (in shares)	13,014,898	12,943,536
Common stock, outstanding (in shares)	13,014,898	12,943,536
Preferred stock, authorized (in shares)	500,000	500,000
Preferred stock, issued (in shares)	0	0

Statements of Income

Statements of Income - USD ($) $ in Thousands	12 Months Ended
Statements of Income - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Statements of Income [Abstract]
OPERATING REVENUES	$ 51,578	$ 48,437
OPERATING EXPENSES:
Operation and maintenance	10,387	9,670
Administrative and general	8,517	8,095
Depreciation and amortization	7,688	7,010
Taxes other than income taxes	1,200	1,145
Operating expenses	27,792	25,920
Operating income	23,786	22,517
OTHER INCOME (EXPENSES):
Interest on debt	(5,124)	(5,509)
Allowance for funds used during construction	366	229
Other pension costs	(1,451)	(1,285)
Other income (expenses), net	(935)	(85)
Other income (expenses)	(7,144)	(6,650)
Income before income taxes	16,642	15,867
Income taxes	2,240	2,491
Net Income	$ 14,402	$ 13,376
Basic Earnings Per Share (in dollars per share)	$ 1.11	$ 1.04
Diluted Earnings Per Share (in dollars per share)	$ 1.11	$ 1.04

Statements of Common Stockholde

Statements of Common Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2017	$ 79,201	$ 40,204	$ 119,405
Balance (in shares) at Dec. 31, 2017	12,872,742
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 0	13,376	13,376
Cash dividends declared	0	(8,690)	(8,690)
Issuance of common stock under dividend reinvestment, direct stock and employee stock purchase plans	$ 2,024	0	2,024
Issuance of common stock under dividend reinvestment, direct stock and employee stock purchase plans (in shares)	67,051
Stock-based compensation	$ 80	0	80
Stock-based compensation (in shares)	3,743
Balance at Dec. 31, 2018	$ 81,305	44,890	$ 126,195
Balance (in shares) at Dec. 31, 2018	12,943,536		12,943,536
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 0	14,402	$ 14,402
Cash dividends declared	0	(9,083)	(9,083)
Issuance of common stock under dividend reinvestment, direct stock and employee stock purchase plans	$ 2,505	0	2,505
Issuance of common stock under dividend reinvestment, direct stock and employee stock purchase plans (in shares)	64,399
Stock-based compensation	$ 166	0	166
Stock-based compensation (in shares)	6,963
Balance at Dec. 31, 2019	$ 83,976	$ 50,209	$ 134,185
Balance (in shares) at Dec. 31, 2019	13,014,898		13,014,898

Statements of Common Stockhol_2

Statements of Common Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared (in dollars per share)	$ 0.7001	$ 0.6731

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
Statements of Cash Flows - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 14,402	$ 13,376
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	7,688	7,010
Stock-based compensation	166	80
Increase in deferred income taxes	641	58
Other	251	295
Changes in assets and liabilities:
(Increase) decrease in accounts receivable and unbilled revenues	282	(483)
Increase in recoverable income taxes	(547)	0
Increase in materials and supplies, prepaid expenses, regulatory and other assets	(5,903)	(6,094)
Increase in accounts payable, accrued compensation and benefits, accrued expenses, deferred employee benefits, regulatory liabilities, and other deferred credits	2,129	4,508
Decrease in accrued interest and taxes	(228)	(378)
Net cash provided by operating activities	18,881	18,372
CASH FLOWS FROM INVESTING ACTIVITIES:
Utility plant additions, including debt portion of allowance for funds used during construction of $205 in 2019, and $128 in 2018	(18,425)	(16,882)
Acquisition of wastewater system	(2,112)	0
Cash received from surrender of life insurance policies	0	108
Net cash used in investing activities	(20,537)	(16,774)
CASH FLOWS FROM FINANCING ACTIVITIES:
Customers' advances for construction and contributions in aid of construction	1,695	1,998
Repayments of customer advances	(396)	(409)
Proceeds of long-term debt issues	94,043	28,762
Debt issuance costs	(613)	0
Repayments of long-term debt	(85,906)	(25,691)
Repayments under short-term line of credit agreements	(1,000)	0
Changes in cash overdraft position	314	301
Issuance of common stock	2,505	2,024
Dividends paid	(8,986)	(8,583)
Net cash provided by (used in) financing activities	1,656	(1,598)
Net change in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	2	2
Cash and cash equivalents at end of period	2	2
Cash paid during the period for:
Interest, net of amounts capitalized	4,821	5,236
Income taxes	$ 2,230	$ 2,901
Supplemental schedule of non-cash investing and financing activities:
Accounts payable includes $1,029 in 2019 and $1,100 in 2018 for the construction of utility plant.

Statements of Cash Flows (Paren

Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM INVESTING ACTIVITIES:
Utility plant additions, debt portion of allowance for funds used during construction	$ 205	$ 128
Supplemental schedule of non-cash investing and financing activities:
Accounts payable for construction of utility plant	$ 1,029	$ 1,100

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
Significant Accounting Policies	Dec. 31, 2019
Significant Accounting Policies [Abstract]
Significant Accounting Policies	1. Significant Accounting Policies The primary business of The York Water Company, or the Company, is to impound, purify and distribute water. The Company also owns and operates two wastewater collection systems and two wastewater collection and treatment systems. The Company operates within its franchised territory located in York and Adams Counties, Pennsylvania, and is subject to regulation by the Pennsylvania Public Utility Commission, or PPUC. The following summarizes the significant accounting policies employed by The York Water Company. Utility Plant and Depreciation The cost of additions includes contracted cost, direct labor and fringe benefits, materials, overhead and, for certain utility plant, allowance for funds used during construction. In accordance with regulatory accounting requirements, water and wastewater systems acquired are recorded at estimated original cost of utility plant when first devoted to utility service and the applicable depreciation is recorded to accumulated depreciation. The difference between the estimated original cost less applicable accumulated depreciation, and the purchase price and acquisition costs is recorded as an acquisition adjustment within utility plant as permitted by the PPUC. At December 31, 2019 and 2018, utility plant includes a net credit acquisition adjustment of $3,318 and $3,108, respectively. For those amounts approved by the PPUC, the net acquisition adjustment is being amortized over the remaining life of the respective assets. Certain amounts are still awaiting approval from the PPUC before amortization will commence. Amortization amounted to $61 and $58 for the years ended December 31, 2019 and 2018, respectively. Upon normal retirement of depreciable property, the estimated or actual cost of the asset is credited to the utility plant account, and such amounts, together with the cost of removal less salvage value, are charged to the reserve for depreciation. To the extent the Company recovers cost of removal or other retirement costs through rates after the retirement costs are incurred, a regulatory asset is reported. Gains or losses from abnormal retirements are reflected in income currently. The straight-line remaining life method is used to compute depreciation on utility plant cost, exclusive of land and land rights. Annual provisions for depreciation of transportation and mechanical equipment included in utility plant are computed on a straight-line basis over the estimated service lives. Such provisions are charged to clearing accounts and apportioned therefrom to operating expenses and other accounts in accordance with the Uniform System of Accounts as prescribed by the PPUC. The Company charges to maintenance expense the cost of repairs and replacements and renewals of minor items of property. Maintenance of transportation equipment is charged to clearing accounts and apportioned therefrom in a manner similar to depreciation. The cost of replacements, renewals and betterments of units of property is capitalized to the utility plant accounts. The following remaining lives are used for financial reporting purposes: December 31 Approximate range Utility Plant Asset Category 2019 2018 of remaining lives Mains and accessories $ 200,954 $ 190,679 11 – 86 years Services, meters and hydrants 77,501 74,178 17 – 51 years Operations structures, reservoirs and water tanks 63,530 61,868 10 – 58 years Pumping and treatment equipment 33,124 32,575 7 – 30 years Office, transportation and operating equipment 14,464 13,531 3 – 23 years Land and other non-depreciable assets 3,393 3,202 – Utility plant in service 392,966 376,033 Construction work in progress 8,417 4,751 – Total Utility Plant $ 401,383 $ 380,784 The effective rate of depreciation was 2.29% in 2019 and 2.21% in 2018, on average utility plant, net of customers' advances and contributions. Larger depreciation provisions resulting from allowable accelerated methods are deducted for tax purposes. Cash and Cash Equivalents For the purposes of the statements of cash flows, the Company considers all highly liquid debt instruments purchased with an original maturity of three months or less to be cash equivalents except for those instruments earmarked to fund construction expenditures or repay long-term debt. The Company periodically maintains cash balances in major financial institutions in excess of the federally insured limit by the Federal Deposit Insurance Corporation (FDIC). The Company has not experienced any losses and believes it is not exposed to any significant credit risk on cash and cash equivalents. Accounts Receivable Accounts receivable are stated at outstanding balances, less a reserve for doubtful accounts. The reserve for doubtful accounts is established through provisions charged against income. Accounts deemed to be uncollectible are charged against the reserve and subsequent recoveries, if any, are credited to the reserve. The reserve for doubtful accounts is maintained at a level considered adequate to provide for losses that can be reasonably anticipated. Management's periodic evaluation of the adequacy of the reserve is based on past experience, agings of the receivables, adverse situations that may affect a customer's ability to pay, current economic conditions, and other relevant factors. This evaluation is inherently subjective. Unpaid balances remaining after the stated payment terms are considered past due. Materials and Supplies Inventories Materials and supplies inventories are stated at cost. Costs are determined using the average cost method. Note Receivable Note receivable is recorded at cost and represents amounts due from a municipality for construction of water mains in their municipality. Management, considering current information and events regarding the borrowers' ability to repay their obligations, considers a note to be impaired when it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the note agreement. When a note is considered to be impaired, the carrying value of the note is written down. The amount of the impairment is measured based on the present value of expected future cash flows discounted at the note's effective interest rate. Regulatory Assets and Liabilities The Company is subject to the provisions of generally accepted accounting principles regarding rate-regulated entities. The accounting standards provide for the recognition of regulatory assets and liabilities as allowed by regulators for costs or credits that are reflected in current customer rates or are considered probable of being included in future rates. The regulatory assets or liabilities are then relieved as the cost or credit is reflected in rates. Regulatory assets represent costs that are expected to be fully recovered from customers in future rates while regulatory liabilities represent amounts that are expected to be refunded to customers in future rates. These deferred costs have been excluded from the Company’s rate base and, therefore, no return is being earned on the unamortized balances. Regulatory assets and liabilities are comprised of the following: December 31 Remaining Recovery 2019 2018 Periods Assets Income taxes $ 24,405 $ 21,432 Various Postretirement benefits 365 3,071 5 – 10 years Unrealized swap losses 2,227 1,799 1 – 10 years Utility plant retirement costs 5,012 4,841 5 years Customer-owned lead service line replacements 944 304 Various Income taxes on customers' advances for construction and contributions in aid of construction 998 577 Various Service life study expenses 13 18 3 years Rate case filing expenses 225 311 2 years $ 34,189 $ 32,353 Liabilities Excess accumulated deferred income taxes on accelerated depreciation $ 14,008 $ 14,184 Various Income taxes 7,494 6,979 Various IRS TPR catch-up deduction 3,671 3,887 14 years Revenue reduction for tax rate change 226 1,764 1 year $ 25,399 $ 26,814 The regulatory asset for income taxes includes (a) deferred state income taxes related primarily to differences between book and tax depreciation expense, (b) deferred income taxes related to the differences that arise between specific asset improvement costs capitalized for book purposes and deducted as a repair expense for tax purposes, and (c) deferred income taxes associated with the gross-up of revenues related to the differences. These assets are recognized for ratemaking purposes on a cash or flow-through basis and will be recovered in rates as they reverse. Postretirement benefits include the difference between contributions and deferred pension expense and the underfunded status of the pension plans. The underfunded status represents the difference between the projected benefit obligation and the fair market value of the assets. This asset is expected to be recovered in future years as additional contributions are made or markets continue to generate positive returns. The recovery period is dependent on contributions made to the plans, plan asset performance and the discount rate used to value the obligations. The period is estimated at between 5 and 10 years. The Company uses regulatory accounting treatment to defer the mark-to-market unrealized gains and losses on its interest rate swap to reflect that the gain or loss is included in the ratemaking formula when the transaction actually settles. The value of the swap as of the balance sheet date is recorded as part of other deferred credits. Realized gains or losses on the swap will be recorded as interest expense in the statement of income over its remaining term of 10 years. Utility plant retirement costs represents costs already incurred for the removal of assets, which are expected to be recovered over a five-year period in rates, through depreciation expense. The Company was granted approval by the PPUC to modify its tariff to replace lead customer-owned service lines that are discovered when the Company replaces its lead service lines over the remaining three years, and to include the cost of the annual replacement of up to 400 lead customer-owned service lines whenever they are discovered, regardless of the material used for the company-owned service line over nine years. The tariff modification allows the Company to replace customer-owned service lines at its own initial cost and record the costs as a regulatory asset to be recovered in future base rates to customers. The recovery period was established in the most recent rate order at four years beginning March 1, 2019. The recovery period for the customer-owned lead service line replacements completed subsequent to the most recent rate order will begin after the next rate order. Service life study expenses are deferred and amortized over their remaining life of three years. Rate case filing expenses are deferred and amortized over their remaining life of two years. Pursuant to the Tax Cuts and Jobs Act of 2017, or 2017 Tax Act, customers’ advances for construction and contributions in aid of construction are considered taxable income. The Company’s tariff allows the Company to record these income taxes for inclusion in rate base. This asset is recognized for ratemaking purposes on a cash or flow-through basis and will be recovered in rates as it reverses. Under normalization rules applicable to public utility property included in the 2017 Tax Act, the excess accumulated deferred income taxes on accelerated depreciation from lowering of the enacted federal statutory corporate tax rate is recorded as a regulatory liability. The benefit will be given back to customers in rates over the remaining regulatory life of the property. The regulatory liability for income taxes includes deferred taxes related to excess accumulated deferred income taxes on accelerated depreciation, other postretirement benefits, customers’ advances for construction and contributions in aid of construction, and bad debts, as well as deferred investment tax credits. These liabilities will be given back to customers in rates, as tax deductions occur over the next 1 to 50 years. The regulatory liability for the Internal Revenue Service, or IRS, tangible property regulations, or TPR, catch-up deduction represents the tax benefits realized on the Company’s 2014 income tax return for qualifying capital expenditures made prior to 2014. The recovery period was established in the most recent rate order at 15 years beginning March 1, 2019. Pursuant to a rate order approved by the PPUC, the Company has agreed to return the 2018 income tax savings pursuant to the 2017 Tax Act, the associated tax gross-up, and the excess accumulated deferred income taxes on accelerated depreciation to customers as a reconcilable negative surcharge on bills. The Company began giving back the liability over one year beginning March 1, 2019. Other Assets Other assets consist mainly of the cash value of life insurance policies held as an investment by the Company for reimbursement of costs and benefits associated with its supplemental retirement and deferred compensation programs. Deferred Debt Expense Deferred debt expense is amortized on a straight-line basis over the term of the related debt and is presented on the balance sheet as a direct reduction from long-term debt. Customers' Advances for Construction Customer advances are cash payments from developers, municipalities, customers or builders for construction of utility plant, and are refundable upon completion of construction, as operating revenues are earned. If the Company loans funds for construction to the customer, the refund amount is credited to the note receivable rather than paid out in cash. After all refunds to which the customer is entitled are made, any remaining balance is transferred to contributions in aid of construction. Contributions in Aid of Construction Contributions in Aid of Construction is composed of (i) direct, non-refundable contributions from developers, customers or builders for construction of water infrastructure and (ii) customer advances that have become non-refundable. Contributions in aid of construction are deducted from the Company’s rate base, and therefore, no return is earned on property financed with contributions. The PPUC requires that contributions received remain on the Company’s balance sheets indefinitely as a long-term liability. Interest Rate Swap Agreement The Company is exposed to certain risks relating to its ongoing business operations. The primary risk managed by using derivative instruments is interest rate risk. The Company utilizes an interest rate swap agreement to convert its variable-rate debt to a fixed rate. Interest rate swaps are contracts in which a series of interest rate cash flows are exchanged over a prescribed period. The notional amount on which the interest payments are based is not exchanged. The Company has designated the interest rate swap agreement as a cash flow hedge, classified as a financial derivative used for non-trading activities. The accounting standards regarding accounting for derivatives and hedging activities require companies to recognize all derivative instruments as either assets or liabilities at fair value on the balance sheets. In accordance with the standards, the interest rate swap is recorded on the balance sheets in other deferred credits at fair value. The Company uses regulatory accounting treatment rather than hedge accounting to defer the unrealized gains and losses on its interest rate swap. These unrealized gains and losses are recorded as a regulatory asset. Based on current ratemaking treatment, the Company expects the gains and losses to be recognized in rates and in interest expense as the swap settlements occur. Swap settlements are recorded in the income statement with the hedged item as interest expense. Swap settlements resulted in the reclassification from regulatory assets to interest expense of $221 in 2019 and $236 in 2018. The overall swap result was a (gain) loss of $649 in 2019 and $(137) in 2018. During the twelve months ending December 31, 2020, the Company expects to reclassify $268 (before tax) from regulatory assets to interest expense. The interest rate swap will expire on October 1, 2029. Stock-Based Compensation The Company records compensation expense in the financial statements for stock-based awards based on the grant date fair value of those awards. Stock-based compensation expense is recognized over the requisite service periods of the awards on a straight-line basis, which is generally commensurate with the vesting term. Forfeitures are recognized as they occur. Income Taxes Certain income and expense items are accounted for in different time periods for financial reporting than for income tax reporting purposes. Deferred income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. To the extent such income taxes increase or decrease future rates, an offsetting regulatory asset or liability has been recorded. Investment tax credits have been deferred and are being amortized to income over the average estimated service lives of the related assets. As of December 31, 2019 and 2018, deferred investment tax credits amounted to $539 and $578, respectively. The Company filed for a change in accounting method under the IRS TPR effective in 2014. Under the change in accounting method, the Company is permitted to deduct the costs of certain asset improvements that were previously being capitalized and depreciated for tax purposes as an expense on its income tax return. The Company was permitted to make this deduction for prior years (the “catch-up deduction”) and each year going forward, beginning with 2014 (the “ongoing deduction”). After receiving approval from the PPUC in its most recent rate order, the Company began to recognize the catch-up deduction, recorded as a regulatory liability, over 15 years beginning March 1, 2019. The ongoing deduction results in a reduction in the effective income tax rate, a net reduction in income tax expense, and a reduction in the amount of income taxes currently payable. The catch-up deduction resulted in a decrease in current income taxes payable and an increase to regulatory liabilities. Both the ongoing and catch-up deductions resulted in increases to deferred tax liabilities and regulatory assets representing the appropriate book and tax basis difference on capital additions. The 2017 Tax Act, among other things, reduces the federal statutory corporate tax rate for tax years beginning in 2018 from 34% to 21%, eliminates certain deductions, and eliminates bonus depreciation on qualified water and wastewater property. This resulted in the remeasurement of the federal portion of the Company’s deferred taxes as of December 31, 2017 to the 21% rate. The effect was recognized in income for the year ended December 31, 2017 for all deferred tax assets and liabilities except accelerated depreciation. Under normalization rules applicable to public utility property included in the 2017 Tax Act, the excess accumulated deferred income taxes on accelerated depreciation is recorded as a regulatory liability. The regulatory liability is a temporary difference so a deferred tax asset is recorded including the gross-up of revenue necessary to return, in rates, the effect of the temporary difference. Allowance for Funds Used During Construction Allowance for funds used during construction (AFUDC) represents the estimated cost of funds used for construction purposes during the period of construction. These costs are reflected as non-cash income during the construction period and as an addition to the cost of plant constructed. AFUDC includes the net cost of borrowed funds and a rate of return on other funds. The PPUC approved rate of 10.04% was applied for 2019 and 2018. AFUDC is recovered through water and wastewater rates as utility plant is depreciated. Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Impact of Recent Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842)

Acquisitions

Acquisitions	12 Months Ended
Acquisitions	Dec. 31, 2019
Acquisitions [Abstract]
Acquisitions	2. Acquisitions On August 29, 2019, the Company completed the acquisition of the wastewater collection assets of the Jacobus Borough Sewer Authority in York County, Pennsylvania. The Company began operating the existing collection facilities on August 30, 2019. The acquisition resulted in the addition of approximately 700 wastewater customers with purchase price and acquisition cost of approximately $2,112, which is less than the depreciated original cost of the assets. The Company recorded a negative acquisition adjustment of approximately $271 and will seek approval from the PPUC to amortize the acquisition adjustment over the remaining life of the acquired assets. This acquisition is immaterial to Company results.

Accounts Receivable and Contrac

Accounts Receivable and Contract Assets	12 Months Ended
Accounts Receivable and Contract Assets	Dec. 31, 2019
Accounts Receivable and Contract Assets [Abstract]
Accounts Receivable and Contract Assets	3. Accounts Receivable and Contract Assets Accounts receivable and contract assets are summarized in the following table: As of As of Dec. 31, 2019 Dec. 31, 2018 Change Accounts receivable – customers $ 4,574 $ 4,731 $ (157 ) Other receivables 152 385 (233 ) 4,726 5,116 (390 ) Less: allowance for doubtful accounts (305 ) (305 ) – Accounts receivable, net $ 4,421 $ 4,811 $ (390 ) Unbilled revenue $ 2,276 $ 2,427 $ (151 ) Differences in timing of revenue recognition, billings, and cash collections result in receivables and contract assets. Generally, billing occurs subsequent to revenue recognition, resulting in a contract asset reported as unbilled revenue on the balance sheet. The Company does not receive advances or deposits from customers before revenue is recognized so no contract liabilities are reported. Accounts receivable are recorded when the right to consideration becomes unconditional and are presented separately on the balance sheet. The changes in accounts receivable – customers and in unbilled revenue were primarily due to normal timing difference between performance and the customer’s payments.

Note Receivable and Customers'

Note Receivable and Customers' Advances for Construction	12 Months Ended
Note Receivable and Customers' Advances for Construction	Dec. 31, 2019
Note Receivable and Customers' Advances for Construction [Abstract]
Note Receivable and Customers' Advances for Construction	4. Note Receivable and Customers' Advances for Construction The Company entered into an agreement with a municipality to extend water service into a previously formed water district. The Company loaned funds to the municipality to cover the costs related to the project. The municipality concurrently advanced these funds back to the Company in the form of customers' advances for construction. The municipality is required by enacted ordinance to charge application fees and water revenue surcharges (fees) to customers connected to the system, which are remitted to the Company. The note principal and the related customer advance are reduced periodically as operating revenues are earned by the Company from customers connected to the system and refunds of the advance are made. There is no due date for the notes or expiration date for the advance. The Company recorded interest income of $121 in 2019 and $105 in 2018. The interest rate on the note outstanding is 7.5%. Included in the accompanying balance sheets at December 31, 2019 and 2018 were the following amounts related to this project. 2019 2018 Note receivable, including interest $ 255 $ 255 Customers' advances for construction 303 305 The Company has other customers' advances for construction totaling $7,541 and $6,544 at December 31, 2019 and 2018, respectively.

Common Stock and Earnings Per S

Common Stock and Earnings Per Share	12 Months Ended
Common Stock and Earnings Per Share	Dec. 31, 2019
Common Stock and Earnings Per Share [Abstract]
Common Stock and Earnings Per Share	5. Common Stock and Earnings Per Share Net income of $14,402 and $13,376 for the years ended December 31, 2019 and 2018 respectively, is used to calculate both basic and diluted earnings per share. Basic net income per share is based on the weighted average number of common shares outstanding. Diluted net income per share is based on the weighted average number of common shares outstanding plus potentially dilutive shares. The dilutive effect of employee stock-based compensation is included in the computation of diluted net income per share. The dilutive effect of stock-based compensation is calculated using the treasury stock method and expected proceeds upon exercise or issuance of the stock-based compensation. The following table summarizes the shares used in computing basic and diluted net income per share: 2019 2018 Weighted average common shares, basic 12,964,080 12,903,568 Effect of dilutive securities: Employee stock-based compensation 2,212 268 Weighted average common shares, diluted 12,966,292 12,903,836 Under the employee stock purchase plan, all full-time employees who have been employed at least ninety consecutive days may purchase shares of the Company's common stock limited to 10% of gross compensation. The purchase price is 95% of the fair market value (as defined). Shares issued during 2019 and 2018 were 3,914 and 5,187, respectively. As of December 31, 2019, 61,725 authorized shares remain unissued under the plan. The Company has a Dividend Reinvestment and Direct Stock Purchase and Sale Plan (“the Plan”), which is available to both current shareholders and the general public. On November 8, 2019, the Company filed a Registration Statement on Form S-3 with the Securities and Exchange Commission (SEC) to authorize an additional 157,000 shares and rollover the unissued 344,379 shares authorized under the 2016 Form S-3, for issuance under the new Prospectus for the Plan. Under the optional dividend reinvestment portion of the Plan, holders of the Company's common stock may purchase additional shares instead of receiving cash dividends. The purchase price is 95% of the fair market value (as defined). Under the direct stock purchase portion of the Plan, purchases are made monthly at 100% of the stock’s fair market value, as defined in the new Prospectus. The Registration Statement was declared effective by the SEC on November 18, 2019. Shares issued during 2019 and 2018 were 60,485 and 61,864, respectively. As of December 31, 2019, 475,889 authorized shares remain unissued under the Plan. On March 11, 2013, the Board of Directors, or the Board, authorized a share repurchase program granting the Company authority to repurchase up to 1,200,000 shares of the Company’s common stock from time to time. The stock repurchase program has no specific end date and the Company may repurchase shares in the open market or through privately negotiated transactions. The Company may suspend or discontinue the repurchase program at any time. During both 2019 and 2018, the Company did not repurchase or retire any shares. As of December 31, 2019, 618,004 shares remain available for repurchase.

Long-Term Debt and Short-Term B

Long-Term Debt and Short-Term Borrowings	12 Months Ended
Long-Term Debt and Short-Term Borrowings	Dec. 31, 2019
Long-Term Debt and Short-Term Borrowings [Abstract]
Long-Term Debt and Short-Term Borrowings	6. Long-Term Debt and Short-Term Borrowings Long-term debt as of December 31, 2019 and 2018 is summarized in the following table: 2019 2018 10.17% Senior Notes, Series A, due 2019 $ – $ 6,000 9.60% Senior Notes, Series B, due 2019 – 5,000 1.00% Pennvest Note, due 2019 – 30 10.05% Senior Notes, Series C, due 2020 6,500 6,500 8.43% Senior Notes, Series D, due 2022 7,500 7,500 Variable Rate Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds, Series 2008A, due 2029 12,000 12,000 4.75% York County Industrial Development Authority Revenue Bonds, Series 2006, due 2036 – 10,500 3.00% Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds, Series A of 2019, due 2036 10,500 – 4.50% Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds, Series 2014, due 2038 – 14,870 3.10% Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds, Series B of 2019, due 2038 14,870 – 5.00% Monthly Senior Notes, Series 2010A, due 2040 – 15,000 3.23% Senior Notes, due 2040 15,000 – 4.00% - 4.50% York County Industrial Development Authority Exempt Facilities Revenue Bonds, Series 2015, due 2029 - 2045 10,000 10,000 4.54% Senior Notes, due 2049 20,000 – Committed Lines of Credit, due 2021 7,672 8,508 Total long-term debt 104,042 95,908 Less discount on issuance of long-term debt (192 ) (204 ) Less unamortized debt issuance costs (2,815 ) (2,346 ) Less current maturities (6,500 ) (30 ) Long-term portion $ 94,535 $ 93,328 Payments due by year as of December 31, 2019: 2020 2021 2022 2023 2024 $ 6,500 $ 19,672 $ 7,500 $ – $ – Payments due in 2021 include payback of the committed line of credit. The committed line of credit is reviewed annually, and upon favorable outcome, would likely be extended for another year. Payments due in 2021 also include potential payments of $12,000 on the variable rate bonds (due 2029) which would only be payable if all bonds were tendered and could not be remarketed, or in the event the Company was unable to, or chose not to, renew the letter of credit backing the bonds. There is currently no such indication of this happening. Fixed Rate Long-Term Debt The Pennsylvania Economic Development Financing Authority, or PEDFA, Series 2014 Bonds contained both optional and special redemption provisions. Under the optional provisions, the Company could redeem all or a portion of the bonds on or after May 1, 2019. The Company redeemed these bonds on October 8, 2019. Under the special provisions, representatives of deceased beneficial owners of the bonds had the right to request redemption prior to the stated maturity of all or part of their interest in the bonds beginning on or after May 1, 2014. The Company was not obligated to redeem any individual interest exceeding $25, or aggregate interest exceeding $300, in any annual period. In 2019 and 2018, no bonds were retired under these provisions. On January 31, 2019, the Company entered into a note purchase agreement with certain institutional investors relating to the private placement of $20,000 aggregate principal amount of the Company’s senior notes. The senior notes bear interest at 4.54% per annum payable semiannually and mature on January 31, 2049. The senior notes are unsecured and unsubordinated obligations of the Company. The Company received net proceeds, after deducting issuance costs, of approximately $19,820. The net proceeds were used to refinance the $11,000 aggregate principal amount of the Company’s 10.17% Series A Senior Notes due February 1, 2019 and the 9.60% Series B Senior Notes due February 1, 2019, and to refinance line of credit borrowings incurred by the Company as interim financing for various capital projects of the Company. On October 1, 2019, the Company entered into a note purchase agreement with certain institutional investors relating to the private placement of $15,000 aggregate principal amount of the Company’s senior notes. The senior notes bear interest at 3.23% per annum payable semiannually and mature on October 1, 2040. The senior notes are unsecured and unsubordinated obligations of the Company. The Company received net proceeds, after deducting issuance costs, of approximately $14,888. The net proceeds were used to refinance the $15,000 aggregate principal amount of the Company’s 5.00% Monthly Senior Notes Series 2010A due October 1, 2040. On October 8, 2019, the Pennsylvania Economic Development Financing Authority, or PEDFA, issued and sold $10,500 aggregate principal amount of PEDFA Exempt Facilities Revenue Refunding Bonds, Series A of 2019, or the Series A Bonds, and $14,870 aggregate principal amount of PEDFA Exempt Facilities Revenue Refunding Bonds, Series B of 2019, or the Series B Bonds, for the Company's benefit pursuant to the terms of a trust indenture, dated as of September 1, 2019, between the PEDFA and Manufacturers and Traders Trust Company, as trustee. The PEDFA then loaned the proceeds of the issuance and sale of the Series A and the Series B Bonds to the Company pursuant to a loan agreement dated as of September 1, 2019, between the Company and the PEDFA. The Series A Bonds, and therefore the loan, bears interest at 3.00% per annum payable semiannually and the maturity date of the loan is October 1, 2036 subject to optional and mandatory redemption provisions. The Series B Bonds, and therefore the loan, bears interest at 3.10% per annum payable semiannually and the maturity date of the loan is November 1, 2038 subject to optional and mandatory redemption provisions. Amounts outstanding under the loan agreement are direct, unsecured and unsubordinated obligations of the Company. The Company received net proceeds, after deducting issuance costs, of approximately $25,049. The net proceeds were used to refinance the $10,500 aggregate principal amount of the Company’s 4.75% York County Industrial Development Authority Revenue Bonds Series 2006 due October 1, 2036 and the $14,870 aggregate principal amount of the Company’s 4.50% PEDFA Exempt Facilities Revenue Refunding Bonds Series 2014 due November 1, 2038. Variable Rate Long-Term Debt On May 7, 2008, the PEDFA issued $12,000 aggregate principal amount of PEDFA Exempt Facilities Revenue Refunding Bonds, Series A of 2008 (the "Series A Bonds") for the Company's benefit pursuant to the terms of a trust indenture, dated as of May 1, 2008, between the PEDFA and Manufacturers and Traders Trust Company, as trustee. The PEDFA then loaned the proceeds of the offering of the Series A Bonds to the Company pursuant to a loan agreement, dated as of May 1, 2008, between the Company and the PEDFA. The loan agreement provides for a $12,000 loan with a maturity date of October 1, 2029. Amounts outstanding under the loan agreement are the Company’s direct general obligations. The proceeds of the loan were used to redeem the PEDFA Exempt Facilities Revenue Bonds, Series B of 2004 (the “2004 Series B Bonds”). The 2004 Series B Bonds were redeemed because the bonds were tendered and could not be remarketed due to the downgrade of the bond insurer’s credit rating. Borrowings under the loan agreement bear interest at a variable rate as determined by PNC Capital Markets, as remarketing agent, on a periodic basis elected by the Company, which has currently elected that the interest rate be determined on a weekly basis. The remarketing agent determines the interest rate based on the current market conditions in order to determine the lowest interest rate which would cause the Series A Bonds to have a market value equal to the principal amount thereof plus accrued interest thereon. The variable interest rate under the loan agreement averaged 1.50% in 2019 and 1.46% in 2018. As of December 31, 2019 and 2018, the interest rate was 1.78% and 1.75%, respectively. The holders of the $12,000 Series A Bonds may tender their bonds at any time. When the bonds are tendered, they are subject to an annual remarketing agreement, pursuant to which a remarketing agent attempts to remarket the tendered bonds according to the terms of the indenture. In order to keep variable interest rates down and to enhance the marketability of the Series A Bonds, the Company entered into a Reimbursement, Credit and Security Agreement with PNC Bank, National Association (“the Bank”) dated as of May 1, 2008. This agreement provides for a direct pay letter of credit issued by the Bank to the trustee for the Series A Bonds. The Bank is responsible for providing the trustee with funds for the timely payment of the principal and interest on the Series A Bonds and for the purchase price of the Series A Bonds that have been tendered or deemed tendered for purchase and have not been remarketed. The Company’s responsibility is to reimburse the Bank the same day as regular interest payments are made, and within fourteen months for the purchase price of tendered bonds that have not been remarketed. The reimbursement period for the principal is immediate at maturity, upon default by the Company, or if the Bank does not renew the Letter of Credit. The current expiration date of the Letter of Credit is June 30, 2021. It is reviewed annually for a potential extension of the expiration date. The Company may elect to have the Series A Bonds redeemed, in whole or in part, on any date that interest is payable for a redemption price equal to the principal amount thereof plus accrued interest to the date of redemption. The Series A Bonds are also subject to mandatory redemption for the same redemption price in the event that the IRS determines that the interest payable on the Series A Bonds is includable in gross income of the holders of the bonds for federal tax purposes. Interest Rate Swap Agreement In connection with the issuance of the PEDFA 2004 Series B Bonds, the Company entered into an interest rate swap agreement with a counterparty, in the notional principal amount of $12,000. The Company elected to retain the swap agreement for the 2008 Series A Bonds. Interest rate swap agreements derive their value from underlying interest rates. These transactions involve both credit and market risk. The notional amounts are amounts on which calculations, payments, and the value of the derivative are based. Notional amounts do not represent direct credit exposure. Direct credit exposure is limited to the net difference between the calculated amounts to be received and paid, if any. Such difference, which represents the fair value of the swap, is reflected on the Company’s balance sheets. See Note 7 for additional information regarding the fair value of the swap. The interest rate swap will terminate on the maturity date of the 2008 Series A Bonds (which is the same date as the maturity date of the loan under the loan agreement), unless sooner terminated pursuant to its terms. In the event the interest rate swap terminates prior to the maturity date of the 2008 Series A Bonds, either the Company or the swap counterparty may be required to make a termination payment to the other based on market conditions at such time. The Company is exposed to credit-related losses in the event of nonperformance by the counterparty. The Company controls the credit risk of its financial contracts through credit approvals, limits and monitoring procedures, and does not expect the counterparty to default on its obligations. Notwithstanding the terms of the swap agreement, the Company is ultimately obligated for all amounts due and payable under the loan agreement. The interest rate swap agreement contains provisions that require the Company to maintain a credit rating of at least BBB- with Standard & Poor’s. On April 5, 2019, Standard & Poor’s affirmed the Company’s credit rating at A-, with a stable outlook and adequate liquidity. If the Company’s rating were to fall below this rating, it would be in violation of these provisions, and the counterparty to the derivative could request immediate payment if the derivative was in a liability position. The Company’s interest rate swap was in a liability position as of December 31, 2019. If a violation was triggered on December 31, 2019, the Company would have been required to pay the counterparty approximately $2,307. The Company's interest rate swap agreement provides that it pays the counterparty a fixed interest rate of 3.16% on the notional amount of $12,000. In exchange, the counterparty pays the Company a floating interest rate (based on 59% of the U.S. Dollar one-month LIBOR rate) on the notional amount. The floating interest rate paid to the Company is intended, over the term of the swap, to approximate the variable interest rate on the loan agreement and the interest rate paid to bondholders, thereby managing its exposure to fluctuations in prevailing interest rates. The Company's net payment rate on the swap averaged 1.84% in 2019 and 1.97% in 2018. As of December 31, 2019, there was a spread of 75 basis points between the variable rate paid to bondholders and the variable rate received from the swap counterparty, which equated to an overall effective rate of 3.91% (including variable interest and swap payments). As of December 31, 2018, there was a spread of 31 basis points which equated to an overall effective rate of 3.47% (including variable interest and swap payments). Line of Credit Borrowings As of December 31, 2019, the Company maintained unsecured lines of credit aggregating $41,500 with four banks. The first line of credit, in the amount of $13,000, is a committed line of credit with a revolving 2-year maturity (currently May 2021) and carries an interest rate of LIBOR plus 1.20%. The Company had $3,672 and $6,508 outstanding under this line of credit as of December 31, 2019 and 2018, respectively. The second line of credit, in the amount of $11,000, is a committed line of credit, which matures in May 2021 and carries an interest rate of LIBOR plus 1.25%. The third line of credit, in the amount of $7,500, is a committed line of credit, which matures in June 2021 and carries an interest rate of LIBOR plus 1.15%. The Company had $4,000 and $2,000 outstanding under this line of credit as of December 31, 2019 and 2018, respectively. The fourth line of credit, in the amount of $10,000, is a committed line of credit, which matures in September 2020 and carries an interest rate of LIBOR plus 1.20%. The Company had $0 and $1,000 outstanding under this line of credit as of December 31, 2019 and 2018, respectively. Average borrowings outstanding under the lines of credit were $5,070 in 2019 and $7,206 in 2018. The average cost of borrowings under the lines of credit was 3.47% during 2019 and 3.20% during 2018. The weighted average interest rate on the line of credit borrowings was 2.92% as of December 31, 2019 and 3.60% as of December 31, 2018. Debt Covenants and Restrictions The terms of the debt agreements carry certain covenants and limit in some cases the Company's ability to borrow additional funds, to prepay its borrowings and include certain restrictions with respect to declaration and payment of cash dividends and the Company's acquisition of its stock. Under the terms of the most restrictive agreements, the Company cannot borrow in excess of 60% of its utility plant, and cumulative payments for dividends and acquisition of stock since December 31, 1982 may not exceed $1,500 plus net income since that date. As of December 31, 2019, none of the earnings retained in the business are restricted under these provisions. The Company's debt is unsecured. The Company's Pennvest Loan, which matured in 2019, was secured by $800 of receivables. The Company's lines of credit require it to maintain a minimum equity to total capitalization ratio (defined as the sum of equity plus funded debt) and a minimum interest coverage ratio (defined as net income plus interest expense plus income tax expense divided by interest expense). As of December 31, 2019, the Company was in compliance with these covenants.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
Fair Value of Financial Instruments	Dec. 31, 2019
Fair Value of Financial Instruments [Abstract]
Fair Value of Financial Instruments	7. Fair Value of Financial Instruments The accounting standards regarding fair value measurements establish a fair value hierarchy which indicates the extent to which inputs used in measuring fair value are observable in the market. Level 1 inputs include quoted prices for identical instruments and are the most observable. Level 2 inputs include quoted prices for similar assets and observable inputs such as interest rates, commodity rates and yield curves. Level 3 inputs are not observable in the market and include management’s own judgments about the assumptions market participants would use in pricing the asset or liability. The Company has recorded its interest rate swap liability at fair value in accordance with the standards. The liability is recorded under the caption “Other deferred credits” on the balance sheets. The table below illustrates the fair value of the interest rate swap as of the end of the reporting period. Description December 31, 2019 Fair Value Measurements at Reporting Date Using Significant Other Observable Inputs (Level 2) Interest Rate Swap $ 2,248 $ 2,248 Fair values are measured as the present value of all expected future cash flows based on the LIBOR-based swap yield curve as of the date of the valuation. These inputs to this calculation are deemed to be Level 2 inputs. The balance sheet carrying value reflects the Company's credit quality as of December 31, 2019. The rate used in discounting all prospective cash flows anticipated to be made under this swap reflects a representation of the yield to maturity for 30-year debt on utilities rated A- as of December 31, 2019. The use of the Company's credit quality resulted in a reduction in the swap liability of $59 as of December 31, 2019. The fair value of the swap reflecting the Company's credit quality as of December 31, 2018 is shown in the table below. Description December 31, 2018 Fair Value Measurements at Reporting Date Using Significant Other Observable Inputs (Level 2) Interest Rate Swap $ 1,815 $ 1,815 The carrying amount of current assets and liabilities that are considered financial instruments approximates fair value as of the dates presented. The Company's total long-term debt, with a carrying value of $104,042 at December 31, 2019, and $95,908 at December 31, 2018, had an estimated fair value of approximately $115,000 and $105,000, respectively. The estimated fair value of debt was calculated using a discounted cash flow technique that incorporates a market interest yield curve with adjustments for duration and risk profile. These inputs to this calculation are deemed to be Level 2 inputs. The Company recognized its credit rating in determining the yield curve, and did not factor in third party credit enhancements including bond insurance on the 2006 York County Industrial Development Authority issue, which was terminated upon its refinance in 2019, and the letter of credit on the 2008 PEDFA Series A issue. Customers' advances for construction and note receivable have carrying values at December 31, 2019 of $7,844 and $255, respectively. At December 31, 2018, customers' advances for construction and note receivable had carrying values of $6,849 and $255, respectively. The relative fair values of these amounts cannot be accurately estimated since the timing of future payment streams is dependent upon several factors, including new customer connections, customer consumption levels and future rate increases.

Commitments

Commitments	12 Months Ended
Commitments	Dec. 31, 2019
Commitments [Abstract]
Commitments	8. Commitments Based on its capital budget, the Company anticipates construction and acquisition expenditures for 2020 and 2021 of approximately $29,500 and $27,000, respectively, exclusive of any acquisitions not yet approved. The Company plans to finance ongoing capital expenditures with internally-generated funds, borrowings against the Company’s lines of credit, proceeds from the issuance of common stock under its dividend reinvestment and direct stock purchase and sale plan and ESPP, potential common stock or debt issues and customer advances and contributions. The Company entered into a consent order agreement with the Pennsylvania Department of Environmental Protection in December 2016 after the Company determined it exceeded the action level for lead as established by the Lead and Copper Rule, or LCR, issued by the U.S. Environmental Protection Agency. The Company did not have an exceedance in any subsequent compliance test. Under the agreement, the Company committed to exceed the LCR replacement schedule by replacing all of the remaining known company-owned lead service lines within four years from the agreement. The cost for these service line replacements was approximately $2,713 and $2,341 through and is included in utility plant. As of , all known company-owned lead service lines have been replaced. Any additional company-owned lead service lines that are discovered will be replaced but are not expected to have a material impact on the financial position of the Company. The Company was granted approval by the PPUC, to modify its tariff to include the cost of the annual replacement of up to 400 lead customer-owned service lines over nine years from the agreement. The tariff modification allows the Company to replace customer-owned service lines at its own initial cost. The Company will record the costs as a regulatory asset to be recovered in future base rates to customers, over a four-year period. The cost for the customer-owned lead service line replacements was approximately $1,000 and $304 through and is included as a regulatory asset. Based on its experience, the Company estimates that lead customer-owned service lines replacements will cost $1,300. This estimate is subject to adjustment as more facts become available. As of December 31, 2019, approximately 31% of the Company's full time employees are under union contract. The current contract was ratified in December 2017 and expires on April 30, 2020. Management is currently preparing for negotiations with the union leadership. The Company expects to reach an operationally and fiscally responsible agreement with no interruption of service. The Company is involved in certain legal and administrative proceedings before various courts and governmental agencies concerning water service and other matters. The Company expects that the ultimate disposition of these proceedings will not have a material effect on the Company's financial position, results of operations and cash flows.

Revenue

Revenue	12 Months Ended
Revenue	Dec. 31, 2019
Revenue [Abstract]
Revenue	9. Revenue The following table shows the Company’s revenues disaggregated by service and customer type. 2019 2018 Water utility service: Residential $ 32,118 $ 30,348 Commercial and industrial 14,161 13,351 Fire protection 3,074 2,931 Wastewater utility service: Residential 1,291 933 Commercial and industrial 280 227 Billing and revenue collection services 70 64 Collection services 52 54 Other revenue 13 22 Total Revenue from Contracts with Customers 51,059 47,930 Rents from regulated property 519 507 Total Operating Revenue $ 51,578 $ 48,437 Utility Service The Company provides utility service as a distinct and single performance obligation to each of its water and wastewater customers. The transaction price is detailed in the tariff pursuant to an order by the PPUC and made publicly available. There is no variable consideration and no free service, special rates, or subnormal charges to any customer. Due to the fact that the contract includes a single performance obligation, no judgment is required to allocate the transaction price. The performance obligation is satisfied over time through the continuous provision of utility service through a stand-ready obligation to perform and the transfer of water or the collection of wastewater through a series of distinct transactions that are identical in nature and have the same pattern of transfer to the customer. The Company uses an output method to recognize the utility service revenue over time. The stand-ready obligation is recognized through the passage of time in the form of a fixed charge and the transfer of water or the collection of wastewater is recognized at a per unit rate based on the actual or estimated flow through the meter. Each customer is invoiced every month and the invoice is due within twenty days. The utility service has no returns or warranties associated with it. No revenue is recognized from performance obligations satisfied in prior periods and no performance obligations remain unsatisfied as of the end of the reporting period. A contract asset for unbilled revenue is recognized for the passage of time and the actual or estimated usage from the latest meter reading to the end of the accounting period. The methodology is standardized and consistently applied to reduce bias and the need for judgment. Billing and Revenue Collection Service The Company provides billing and revenue collection service as distinct performance obligations to three municipalities within the service territory of the Company. The municipalities provide wastewater service to their residents and the Company acts as the billing and revenue collection agent for the municipalities. The transaction price is a fixed amount per bill prepared as established in the contract. There is no variable consideration. Due to the fact that both the billing performance obligation and the revenue collection performance obligation are materially complete by the end of the reporting period, the Company does not allocate the transaction price between the two performance obligations. The performance obligations are satisfied at a point in time when the bills are sent as the municipalities receive all the benefits and bears all of the risk of non-collection at that time. Each municipality is invoiced when the bills are complete and the invoice is due within thirty days. The billing and revenue collection service has no returns or warranties associated with it. No revenue is recognized from performance obligations satisfied in prior periods and no performance obligations remain unsatisfied as of the end of the reporting period. Collection Service The Company provides collection service as a distinct and single performance obligation to several municipalities within the service territory of the Company. The municipalities provide wastewater service to their residents. If those residents are delinquent in paying for their wastewater service, the municipalities request that the Company post for and shut off the supply of water to the premises of those residents. When the resident is no longer delinquent, the Company will restore water service to the premises. The transaction price for each posting, each shut off, and each restoration is a fixed amount as established in the contract. There is no variable consideration. Due to the fact that the contract includes a single performance obligation, no judgment is required to allocate the transaction price. The performance obligation is satisfied at a point in time when the posting, shut off, or restoration is completed as the municipalities receive all the benefits in the form of payment or no longer providing wastewater service. Each municipality is invoiced periodically for the posting, shut offs, and restorations that have been completed since the last billing and the invoice is due within thirty days. The collection service has no returns or warranties associated with it. No revenue is recognized from performance obligations satisfied in prior periods and no performance obligations remain unsatisfied as of the end of the reporting period. A contract asset for unbilled revenue is recognized for postings, shut offs, and restorations that have been completed from the last billing to the end of the accounting period. Service Line Protection Plan The Company provides service line protection as a distinct and single performance obligation to current water customers that choose to participate. The transaction price is detailed in the plan’s terms and conditions and made publicly available. There is no variable consideration. Due to the fact that the contract includes a single performance obligation, no judgment is required to allocate the transaction price. The performance obligation is satisfied over time through the continuous provision of service line protection through a stand-ready obligation to perform. The Company uses an output method to recognize the service line protection revenue over time. The stand-ready obligation is recognized through the passage of time. A customer has a choice to prepay for an entire year or to pay in advance each month. The service line protection plan has no returns or extended warranties associated with it. No revenue is recognized from performance obligations satisfied in prior periods and no material performance obligations remain unsatisfied as of the end of the reporting period.

Rate Matters

Rate Matters	12 Months Ended
Rate Matters	Dec. 31, 2019
Rate Matters [Abstract]
Rate Matters	10. Rate Matters From time to time, the Company files applications for rate increases with the PPUC and is granted rate relief as a result of such requests. The most recent rate request was filed by the Company on May 30, 2018, and sought an annual increase in water rates of $6,399 and an annual increase in wastewater rates of $289. Effective March 1, 2019, the PPUC authorized an increase in water rates designed to produce approximately $3,361 in additional annual revenues and an increase in wastewater rates designed to produce approximately $289 in additional annual revenues. As part of a rate order approved by the PPUC, the Company has agreed to return $2,117 to customers as a reconcilable negative surcharge on their bills generated from March 2019 through February 2020 for the benefit of the lower tax rate effective January 1, 2018 resulting from the enactment of the Tax Cuts and Jobs Act of 2017, or 2017 Tax Act. During the years ended December 31, 2019 and 2018, the Company increased its regulatory liability by reducing revenue by $325 and $1,600, respectively, including the gross-up of revenue necessary to return, in rates, the effect of this temporary tax difference, and reclassified $27 and $164, respectively, from excess accumulated deferred income taxes on accelerated depreciation recorded at December 31, 2017. During the year ended December 31, 2019 the Company returned negative surcharges of $1,891. The PPUC permits water utilities to collect a distribution system improvement charge, or DSIC. The DSIC allows the Company to add a charge to customers' bills for qualified replacement costs of certain infrastructure without submitting a rate filing. This surcharge mechanism typically adjusts periodically based on additional qualified capital expenditures completed or anticipated in a future period. The DSIC is capped at 5% of base rates, and is reset to zero when new base rates that reflect the costs of those additions become effective or when a utility's earnings exceed a regulatory benchmark. The DSIC reset to zero when the new base rates took effect March 1, 2019.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
Employee Benefit Plans	Dec. 31, 2019
Employee Benefit Plans [Abstract]
Employee Benefit Plans	11. Employee Benefit Plans Pensions The Company maintains a general and administrative and a union-represented defined benefit pension plan covering all of its employees hired prior to May 1, 2010. Employees hired after May 1, 2010 are eligible for an enhanced 401(k) plan rather than a defined benefit plan. The benefits under the defined benefit plans are based upon years of service and compensation near retirement. The Company amended its defined benefit pension plans in 2014, generally limiting the years of eligible service under the plans to 30 years. The Company's funding policy is to contribute annually the amount permitted by the PPUC to be collected from customers in rates, but in no case less than the minimum Employee Retirement Income Security Act (ERISA) required contribution. The following table sets forth the plans' funded status as of December 31, 2019 and 2018. The measurement of assets and obligations of the plans is as of December 31, 2019 and 2018. Obligations and Funded Status 2019 2018 Change in Benefit Obligation Pension benefit obligation beginning of year $ 41,511 $ 44,636 Service cost 849 1,015 Interest cost 1,645 1,515 Actuarial (gain) loss 5,241 (4,140 ) Benefit payments (1,716 ) (1,515 ) Pension benefit obligation end of year 47,530 41,511 Change in Plan Assets Fair value of plan assets beginning of year 40,624 41,439 Actual return on plan assets 8,141 (1,600 ) Employer contributions 2,300 2,300 Benefits paid (1,716 ) (1,515 ) Fair value of plan assets end of year 49,349 40,624 Funded Status of Plans at End of Year $ 1,819 $ (887 ) The accounting standards require that the funded status of defined benefit pension plans be fully recognized on the balance sheets. They also call for the unrecognized actuarial gain or loss, the unrecognized prior service cost and the unrecognized transition costs to be adjustments to shareholders’ equity (accumulated other comprehensive income). Due to a rate order granted by the PPUC, the Company is permitted under the accounting standards to defer the charges otherwise recorded in accumulated other comprehensive income as a regulatory asset. Management believes these costs will be recovered in future rates charged to customers. The asset for the funded status of the Company's pension plans as of December 31, 2019 is recorded in "Other assets" on its balance sheets. The liability for the funded status of the Company’s pension plans as of December 31, 2018 is recorded in “Deferred employee benefits” on its balance sheets. In 2019, the plans recognized a significant actuarial loss. The Company adopted the new mortality table (Pri-2012) and the new mortality improvement scale (MP-2019) but recognized a 100 basis point decrease in the discount rate. In 2018, the plans recognized a significant actuarial gain. The Company adopted the new mortality improvement scale (MP-2018) and recognized a 60 basis point increase in the discount rate. The Company uses the corridor method to amortize actuarial gains and losses. Gains and losses over 10% of the greater of pension benefit obligation or the market value of assets are amortized over the average future service of plan participants expected to receive benefits. Changes in plan assets and benefit obligations recognized in regulatory assets are as follows: 2019 2018 Net gain (loss) arising during the period $ (167 ) $ 252 Recognized net actuarial loss (421 ) (406 ) Recognized prior service credit 13 13 Total changes in regulatory asset during the year $ (575 ) $ (141 ) Amounts recognized in regulatory assets that have not yet been recognized as components of net periodic benefit cost consist of the following at December 31: 2019 2018 Net loss $ 8,154 $ 8,742 Prior service credit (76 ) (89 ) Regulatory asset $ 8,078 $ 8,653 Components of net periodic benefit cost are as follows: 2019 2018 Service cost $ 849 $ 1,015 Interest cost 1,645 1,515 Expected return on plan assets (2,733 ) (2,793 ) Amortization of loss 421 406 Amortization of prior service credit (13 ) (13 ) Rate-regulated adjustment 2,131 2,170 Net periodic benefit cost $ 2,300 $ 2,300 Pension service cost is recorded in operating expenses. All other components of net periodic pension cost are recorded as other pension costs in other income (expenses). The rate-regulated adjustment set forth above is required in order to reflect pension expense for the Company in accordance with the method used in establishing water rates. The Company is permitted by rate order of the PPUC to expense pension costs to the extent of contributions and defer the remaining expense to regulatory assets to be collected in rates at a later date as additional contributions are made. During 2019, the deferral decreased by $2,131. The estimated costs for the defined benefit pension plans relating to the December 31, 2019 balance sheet that will be amortized from regulatory assets into net periodic benefit cost over the next fiscal year are as follows: Net loss $ 353 Net prior service credit (13 ) 340 The Company plans to contribute $2,300 to the plans in 2020. The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid in each of the next five years and the subsequent five years in the aggregate: 2020 2021 2022 2023 2024 2025 2029 $ 1,827 $ 1,891 $ 1,964 $ 2,138 $ 2,208 $ 11,830 The following tables show the projected benefit obligation, the accumulated benefit obligation and the fair value of plan assets as of December 31: 2019 2018 Projected benefit obligation $ 47,530 $ 41,511 Fair value of plan assets 49,349 40,624 2019 2018 Accumulated benefit obligation $ 44,587 $ 39,100 Fair value of plan assets 49,349 40,624 Weighted-average assumptions used to determine benefit obligations at December 31: 2019 2018 Discount rate 3.10% 4.10% Rate of compensation increase 2.50% – 3.00% 2.50% – 3.00% Weighted-average assumptions used to determine net periodic benefit cost for years ended December 31: 2019 2018 Discount rate 4.10% 3.50% Expected long-term return on plan assets 6.50% 6.75% Rate of compensation increase 2.50% – 3.00% 2.50% – 3.00% The selected long-term rate of return on plan assets was primarily based on the asset allocation of each of the plan's assets (approximately 50% to 70% equity securities and 30% to 50% fixed income securities). Analysis of the historic returns of these asset classes and projections of expected future returns were considered in setting the long-term rate of return. The investment objective of the Company's defined benefit pension plans is that of Growth and Income. The weighted-average target asset allocations are 50% to 70% equity securities, 30% to 50% fixed income securities, and 0% to 10% reserves (cash and cash equivalents). Within the equity category, the Company's target allocation is approximately 60-95% large cap, 0-25% mid cap, 0-10% small cap, 0-25% International Developed Nations, and 0-10% International Emerging Nations. Within the fixed income category, its target allocation is approximately 15-55% U.S. Treasuries, 0–22% Federal Agency securities, 0-40% corporate bonds, 15-55% mortgage-backed securities, 0-20% international, and 0-20% high yield bonds. The Company's investment performance objectives over a three to five-year period are to exceed the annual rate of inflation as measured by the Consumer Price Index by 3%, and to exceed the annualized total return of specified benchmarks applicable to the funds within the asset categories. Further guidelines within equity securities include: (1) holdings in any one company cannot exceed 5% of the portfolio; (2) a minimum of 20 individual stocks must be included in the domestic stock portfolio; (3) a minimum of 30 individual stocks must be included in the international stock portfolio; (4) equity holdings in any one industry cannot exceed 20-25% of the portfolio; and (5) only U.S.-denominated currency securities are permitted. Further guidelines for fixed income securities include: (1) fixed income holdings in a single issuer are limited to 5% of the portfolio; (2) acceptable investments include money market securities, U.S. Government and its agencies and sponsored entities' securities, mortgage-backed and asset-backed securities, corporate securities and mutual funds offering high yield bond portfolios; (3) purchases must be limited to investment grade or higher; (4) non-U.S. dollar denominated securities are not permissible; and (5) high risk derivatives are prohibited. The fair values of the Company's pension plan assets at December 31, 2019 and 2018 by asset category and fair value hierarchy level are as follows. The majority of the valuations are based on quoted prices on active markets (Level 1), with the remaining valuations based on broker/dealer quotes, active market makers, models, and yield curves (Level 2). Total Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Asset Category 2019 2018 2019 2018 2019 2018 Cash and Money Market Funds (a) $ 682 $ 1,498 $ 682 $ 1,498 $ – $ – Equity Securities: Common Equity Securities (b) 662 512 662 512 – – Equity Mutual Funds (c) 29,677 23,637 29,677 23,637 – – Fixed Income Securities: U.S. Treasury Obligations 615 591 – – 615 591 Corporate and Foreign Bonds (d) 6,078 5,315 – – 6,078 5,315 Fixed Income Mutual Funds (e) 11,635 9,071 11,635 9,071 – – Total Plan Assets $ 49,349 $ 40,624 $ 42,656 $ 34,718 $ 6,693 $ 5,906 (a) The portfolios are designed to keep up to one year of distributions in immediately available funds. (b) This category includes investments in U.S. common stocks and foreign stocks trading in the U.S. widely distributed among consumer discretionary, consumer staples, healthcare, information technology, financial services, telecommunications, industrials, real estate, materials, and energy. The individual stocks are primarily large cap stocks which track with the S&P 500. (c) This category currently includes a majority of investments in closed-end mutual funds as well as domestic equity mutual funds and international mutual funds which give the portfolio exposure to mid and large cap index funds as well as international diversified index funds. (d) This category currently includes only U.S. corporate bonds and notes widely distributed among consumer discretionary, consumer staples, healthcare, information technology, energy, transportation, and financial services. (e) This category includes fixed income investments in mutual funds which include government, corporate and mortgage securities of both the U.S. and other countries. The mortgage-backed securities and non-U.S. corporate and sovereign investments add further diversity to the fixed income portion of the portfolio. Defined Contribution Plan The Company has a savings plan pursuant to the provisions of section 401(k) of the Internal Revenue Code. For employees hired before May 1, 2010, this plan provides for elective employee contributions of up to 15% of compensation and Company matching contributions of 100% of the participant's contribution, up to a maximum annual Company contribution of $2.8 for each employee. Employees hired after May 1, 2010 are entitled to an enhanced feature of the plan. This feature provides for elective employee contributions of up to 15% of compensation and Company matching contributions of 100% of the participant's contribution, up to a maximum of 4% of the employee's compensation. In addition, the Company will make an annual contribution of $1.2 to each employee's account whether or not they defer their own compensation. Employees eligible for this enhanced 401(k) plan feature are not eligible for the defined benefit plans. As of December 31, 2019, 49 employees were participating in the enhanced feature of the plan. The Company's contributions to both portions of the plan amounted to $300 in 2019 and $287 in 2018. Deferred Compensation The Company has non-qualified deferred compensation and supplemental retirement agreements with certain members of management. The future commitments under these arrangements are offset by corporate-owned life insurance policies. At December 31, 2019 and 2018, the present value of the future obligations was approximately $4,416 and $3,955, respectively. The insurance policies included in other assets had a total cash value of approximately $3,667 and $3,402 at December 31, 2019 and 2018, respectively. The Company's net expenses under the plans amounted to $670 in 2019 and $32 in 2018. Other The Company has a retiree life insurance program which pays the beneficiary of a retiree $2 upon the retiree’s death. At December 31, 2019 and 2018, the present value of the future obligations was approximately $137 and $107, respectively. There is no trust or insurance covering this future liability, instead the Company will pay these benefits out of its general assets. The Company’s net (income) expenses under the plan amounted to $34 in 2019 and $(10) in 2018.

Stock Based Compensation

Stock Based Compensation	12 Months Ended
Stock Based Compensation	Dec. 31, 2019
Stock-Based Compensation [Abstract]
Stock-Based Compensation	12. Stock-Based Compensation On May 2, 2016, the Company's stockholders approved The York Water Company Long-Term Incentive Plan, or LTIP. The LTIP was adopted to provide the incentive of long-term stock-based awards to officers, directors and key employees. The LTIP provides for the granting of nonqualified stock options, incentive stock options, stock appreciation rights, performance restricted stock grants and units, restricted stock grants and units, and unrestricted stock grants. A maximum of 100,000 shares of common stock may be issued under the LTIP over the ten-year life of the plan. The maximum number of shares of common stock subject to awards that may be granted to any participant in any one calendar year is 2,000. Shares of common stock issued under the LTIP may be treasury shares or authorized but unissued shares. The LTIP is administered by the Compensation Committee of the Board, or the full Board, provided that the full Board administers the LTIP as it relates to awards to non-employee directors of the Company. The Company filed a registration statement with the SEC on May 11, 2016 covering the offering of stock under the LTIP. The LTIP was effective on July 1, 2016. On November 21, 2016, the Board awarded stock to non-employee directors effective November 28, 2016. This stock award vested immediately. On the same date, the Compensation Committee awarded restricted stock to officers and key employees effective November 28, 2016. This restricted stock award vested ratably over three years beginning November 28, 2016 and has been fully recognized as of December 31, 2019. On April 26, 2017, the Board awarded stock to non-employee directors effective May 1, 2017. This stock award vested immediately. On April 26, 2017, the Compensation Committee awarded restricted stock to officers and key employees effective May 1, 2017. This restricted stock award vests ratably over three years beginning May 1, 2017. On May 7, 2018, the Board awarded stock to non-employee directors effective May 7, 2018. This stock award vested immediately. On May 7, 2018, the Compensation Committee awarded restricted stock to officers and key employees effective May 7, 2018. This restricted stock award vests ratably over three years beginning May 7, 2018. On November 20, 2018, the Board accelerated the vesting period for restricted stock granted in 2016, 2017, and 2018 to one retiring officer from three years to that officer’s 2019 retirement date which has been fully recognized as of December 31, 2019. On May 6, 2019, the Board awarded stock to non-employee directors effective May 6, 2019. This stock award vested immediately. On May 6, 2019, the Compensation Committee awarded restricted stock to officers and key employees effective May 6, 2019. This restricted stock award vests ratably over three years beginning May 6, 2019. On August 19, 2019, the Board accelerated the vesting period for restricted stock granted in 2017, 2018, and 2019 to one retiring officer from three years to that officer’s 2020 retirement date. The restricted stock awards provide the grantee with the rights of a shareholder, including the right to receive dividends and to vote such shares, but not the right to sell or otherwise transfer the shares during the restriction period. As a result, the awards are included in common shares outstanding on the balance sheet. Restricted stock awards result in compensation expense valued at the fair market value of the stock on the date of the grant and are amortized ratably over the restriction period. The following table summarizes the stock grant amounts and activity for the years ended December 31, 2018 and 2019. Number of Shares Grant Date Weighted Average Fair Value Nonvested at beginning of the year 2018 1,127 $37.76 Granted 3,743 $32.70 Vested (1,790 ) $33.90 Forfeited – – Nonvested at end of the year 2018 3,080 $33.85 Granted 6,963 $33.61 Vested (2,701 ) $33.99 Forfeited – – Nonvested at end of the year 2019 7,342 $33.57 For the years ended December 31, 2019 and 2018, the statement of income includes $166 and $80 of stock based compensation and related recognized tax benefits of $48 and $23, respectively. The total fair value of the shares vested in the years ended December 31, 2019 and 2018 was $92 and $61, respectively. Total stock based compensation related to nonvested awards not yet recognized is $246 at December 31, 2019 which will be recognized over the remaining three year vesting period.

Taxes Other than Income Taxes

Taxes Other than Income Taxes	12 Months Ended
Taxes Other than Income Taxes	Dec. 31, 2019
Taxes Other than Income Taxes [Abstract]
Taxes Other than Income Taxes	13. Taxes Other than Income Taxes The following table provides the components of taxes other than income taxes: 2019 2018 Regulatory Assessment $ 285 $ 261 Property 348 345 Payroll, net of amounts capitalized 564 538 Other 3 1 Total taxes other than income taxes $ 1,200 $ 1,145

Income Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2019
Income Taxes [Abstract]
Income Taxes	14. Income Taxes The provisions for income taxes consist of: 2019 2018 Federal current $ 1,148 $ 1,715 State current 451 718 Federal deferred 475 216 State deferred 205 (119 ) Federal investment tax credit, net of current utilization (39 ) (39 ) Total income taxes $ 2,240 $ 2,491 A reconciliation of the statutory Federal tax provision to the total provision follows: 2019 2018 Statutory Federal tax provision $ 3,495 $ 3,332 State income taxes, net of Federal benefit 574 471 IRS TPR deduction (1,642 ) (1,307 ) Tax-exempt interest (25 ) (22 ) Amortization of investment tax credit (39 ) (39 ) Cash value of life insurance 6 (13 ) Amortization of excess accumulated deferred income taxes on accelerated depreciation (149 ) – Other, net 20 69 Total income taxes $ 2,240 $ 2,491 The Company filed for a change in accounting method under the IRS TPR effective in 2014. Under the change in accounting method, the Company is permitted to deduct the costs of certain asset improvements that were previously being capitalized and depreciated for tax purposes as an expense on its income tax return. The Company was permitted to make this deduction for prior years (the “catch-up deduction”) and for each year going forward (the “ongoing deduction”). As a result of the catch-up deduction, income tax benefits of $3,887 were deferred as a regulatory liability. After receiving approval from the PPUC in its most recent rate order, the Company began to recognize the catch-up deduction, recorded as a regulatory liability, over 15 years beginning March 1, 2019. As a result, the Company recognized $216 in income taxes during the year ended December 31, 2019. As a result of the ongoing deduction, the net income tax benefits of $1,426 and $1,307 for the years ended December 31, 2019 and 2018, respectively, reduced income tax expense and flowed-through to net income. The ongoing deduction results in a reduction in the effective income tax rate, a net reduction in income tax expense, and a reduction in the amount of income taxes currently payable. Both the ongoing and catch-up deductions result in increases to deferred tax liabilities and regulatory assets representing the appropriate book and tax basis difference on capital additions. The 2017 Tax Act, among other things, reduces the federal statutory corporate tax rate for tax years beginning in 2018 from 34% to 21%, eliminates certain deductions, and eliminates bonus depreciation on qualified water and wastewater property. This resulted in the remeasurement of the federal portion of the Company’s deferred taxes as of December 31, 2017 to the 21% rate. The effect was recognized in income for the year ended December 31, 2017 for all deferred tax assets and liabilities except accelerated depreciation. Under normalization rules applicable to public utility property included in the 2017 Tax Act, the excess accumulated deferred income taxes on accelerated depreciation is recorded as a regulatory liability. The regulatory liability is a temporary difference so a deferred tax asset is recorded including the gross-up of revenue necessary to return, in rates, the effect of the temporary difference. The Company is recognizing the excess accumulated deferred income taxes on accelerated depreciation, recorded as a regulatory liability, over the remaining useful life of the underlying assets. As a result, the Company recognized $149 in income taxes during the year ended December 31, 2019. The tax effects of temporary differences between book and tax balances that give rise to significant portions of the deferred tax assets and deferred tax liabilities as of December 31, 2019 and 2018 are summarized in the following table: 2019 2018 Deferred tax assets: Reserve for doubtful accounts $ 88 $ 88 Compensated absences 148 147 Deferred compensation 1,276 1,143 Excess accumulated deferred income taxes on accelerated depreciation 4,047 4,098 Deferred taxes associated with the gross-up of revenues necessary to return, in rates, the effect of temporary differences 2,104 2,077 Customers' advances for construction and contributions in aid of construction 998 577 Revenue reduction for tax rate change 7 333 Pensions – 256 Other costs deducted for book, not for tax 69 40 Total deferred tax assets 8,737 8,759 Deferred tax liabilities: Accelerated depreciation 28,891 28,479 Basis differences from IRS TPR 11,311 9,367 Investment tax credit 384 411 Deferred taxes associated with the gross-up of revenues necessary to recover, in rates, the effect of temporary differences 6,987 6,124 Pensions 525 – Tax effect of pension regulatory asset 106 887 Unamortized debt issuance costs 531 197 Other costs deducted for tax, not for book 428 256 Total deferred tax liabilities 49,163 45,721 Net deferred tax liability $ 40,426 $ 36,962 In accordance with accounting standards, the net deferred tax liability is classified as a noncurrent deferred income tax liability on the balance sheets. No valuation allowance was required for deferred tax assets as of December 31, 2019 and 2018. In assessing the value of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities, projected future taxable income, and tax planning strategies in making this assessment. Based upon expected future taxable income and the current regulatory environment, management believes it is more likely than not that the Company will realize the benefits of these deductible differences. The Company determined that there were no uncertain tax positions meeting the recognition and measurement test of the accounting standards recorded in the years that remain open for review by taxing authorities, which are 2016 through 2018 for both federal and state income tax returns. The Company has not yet filed tax returns for 2019. The Company believes that it has fully complied with any changes pursuant to the 2017 Tax Act and has not taken any new positions in its 2019 income tax provision. The Company's policy is to recognize interest and penalties related to income tax matters in other expenses. The Company paid interest and penalties of $0 and $1 for the years ended December 31, 2019 and 2018, respectively.

Schedule II Valuation and Quali

Schedule II Valuation and Qualifying Accounts	12 Months Ended
Schedule II Valuation and Qualifying Accounts	Dec. 31, 2019
Schedule II Valuation and Qualifying Accounts [Abstract]
Schedule II Valuation and Qualifying Accounts	FOR THE TWO YEARS ENDED DECEMBER 31, 2019 Additions Description Balance at Beginning of Year Charged to Cost and Expenses Recoveries Deductions Balance at End of Year FOR THE YEAR ENDED DECEMBER 31, 2019 Reserve for uncollectible accounts $ 305,000 $ 258,542 $ 51,900 $ 310,442 $ 305,000 FOR THE YEAR ENDED DECEMBER 31, 2018 Reserve for uncollectible accounts $ 305,000 $ 250,884 $ 57,633 $ 308,517 $ 305,000 The Deductions column above represents write-offs of accounts receivable during the applicable year.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
Significant Accounting Policies (Policies)	Dec. 31, 2019
Significant Accounting Policies [Abstract]
Utility Plant and Depreciation	Utility Plant and Depreciation The cost of additions includes contracted cost, direct labor and fringe benefits, materials, overhead and, for certain utility plant, allowance for funds used during construction. In accordance with regulatory accounting requirements, water and wastewater systems acquired are recorded at estimated original cost of utility plant when first devoted to utility service and the applicable depreciation is recorded to accumulated depreciation. The difference between the estimated original cost less applicable accumulated depreciation, and the purchase price and acquisition costs is recorded as an acquisition adjustment within utility plant as permitted by the PPUC. At December 31, 2019 and 2018, utility plant includes a net credit acquisition adjustment of $3,318 and $3,108, respectively. For those amounts approved by the PPUC, the net acquisition adjustment is being amortized over the remaining life of the respective assets. Certain amounts are still awaiting approval from the PPUC before amortization will commence. Amortization amounted to $61 and $58 for the years ended December 31, 2019 and 2018, respectively. Upon normal retirement of depreciable property, the estimated or actual cost of the asset is credited to the utility plant account, and such amounts, together with the cost of removal less salvage value, are charged to the reserve for depreciation. To the extent the Company recovers cost of removal or other retirement costs through rates after the retirement costs are incurred, a regulatory asset is reported. Gains or losses from abnormal retirements are reflected in income currently. The straight-line remaining life method is used to compute depreciation on utility plant cost, exclusive of land and land rights. Annual provisions for depreciation of transportation and mechanical equipment included in utility plant are computed on a straight-line basis over the estimated service lives. Such provisions are charged to clearing accounts and apportioned therefrom to operating expenses and other accounts in accordance with the Uniform System of Accounts as prescribed by the PPUC. The Company charges to maintenance expense the cost of repairs and replacements and renewals of minor items of property. Maintenance of transportation equipment is charged to clearing accounts and apportioned therefrom in a manner similar to depreciation. The cost of replacements, renewals and betterments of units of property is capitalized to the utility plant accounts. The following remaining lives are used for financial reporting purposes: December 31 Approximate range Utility Plant Asset Category 2019 2018 of remaining lives Mains and accessories $ 200,954 $ 190,679 11 – 86 years Services, meters and hydrants 77,501 74,178 17 – 51 years Operations structures, reservoirs and water tanks 63,530 61,868 10 – 58 years Pumping and treatment equipment 33,124 32,575 7 – 30 years Office, transportation and operating equipment 14,464 13,531 3 – 23 years Land and other non-depreciable assets 3,393 3,202 – Utility plant in service 392,966 376,033 Construction work in progress 8,417 4,751 – Total Utility Plant $ 401,383 $ 380,784 The effective rate of depreciation was 2.29% in 2019 and 2.21% in 2018, on average utility plant, net of customers' advances and contributions. Larger depreciation provisions resulting from allowable accelerated methods are deducted for tax purposes.
Cash and Cash Equivalents	Cash and Cash Equivalents For the purposes of the statements of cash flows, the Company considers all highly liquid debt instruments purchased with an original maturity of three months or less to be cash equivalents except for those instruments earmarked to fund construction expenditures or repay long-term debt. The Company periodically maintains cash balances in major financial institutions in excess of the federally insured limit by the Federal Deposit Insurance Corporation (FDIC). The Company has not experienced any losses and believes it is not exposed to any significant credit risk on cash and cash equivalents.
Accounts Receivable	Accounts Receivable Accounts receivable are stated at outstanding balances, less a reserve for doubtful accounts. The reserve for doubtful accounts is established through provisions charged against income. Accounts deemed to be uncollectible are charged against the reserve and subsequent recoveries, if any, are credited to the reserve. The reserve for doubtful accounts is maintained at a level considered adequate to provide for losses that can be reasonably anticipated. Management's periodic evaluation of the adequacy of the reserve is based on past experience, agings of the receivables, adverse situations that may affect a customer's ability to pay, current economic conditions, and other relevant factors. This evaluation is inherently subjective. Unpaid balances remaining after the stated payment terms are considered past due.
Materials and Supplies Inventories	Materials and Supplies Inventories Materials and supplies inventories are stated at cost. Costs are determined using the average cost method.
Note Receivable	Note Receivable Note receivable is recorded at cost and represents amounts due from a municipality for construction of water mains in their municipality. Management, considering current information and events regarding the borrowers' ability to repay their obligations, considers a note to be impaired when it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the note agreement. When a note is considered to be impaired, the carrying value of the note is written down. The amount of the impairment is measured based on the present value of expected future cash flows discounted at the note's effective interest rate.
Regulatory Assets and Liabilities	Regulatory Assets and Liabilities The Company is subject to the provisions of generally accepted accounting principles regarding rate-regulated entities. The accounting standards provide for the recognition of regulatory assets and liabilities as allowed by regulators for costs or credits that are reflected in current customer rates or are considered probable of being included in future rates. The regulatory assets or liabilities are then relieved as the cost or credit is reflected in rates. Regulatory assets represent costs that are expected to be fully recovered from customers in future rates while regulatory liabilities represent amounts that are expected to be refunded to customers in future rates. These deferred costs have been excluded from the Company’s rate base and, therefore, no return is being earned on the unamortized balances. Regulatory assets and liabilities are comprised of the following: December 31 Remaining Recovery 2019 2018 Periods Assets Income taxes $ 24,405 $ 21,432 Various Postretirement benefits 365 3,071 5 – 10 years Unrealized swap losses 2,227 1,799 1 – 10 years Utility plant retirement costs 5,012 4,841 5 years Customer-owned lead service line replacements 944 304 Various Income taxes on customers' advances for construction and contributions in aid of construction 998 577 Various Service life study expenses 13 18 3 years Rate case filing expenses 225 311 2 years $ 34,189 $ 32,353 Liabilities Excess accumulated deferred income taxes on accelerated depreciation $ 14,008 $ 14,184 Various Income taxes 7,494 6,979 Various IRS TPR catch-up deduction 3,671 3,887 14 years Revenue reduction for tax rate change 226 1,764 1 year $ 25,399 $ 26,814 The regulatory asset for income taxes includes (a) deferred state income taxes related primarily to differences between book and tax depreciation expense, (b) deferred income taxes related to the differences that arise between specific asset improvement costs capitalized for book purposes and deducted as a repair expense for tax purposes, and (c) deferred income taxes associated with the gross-up of revenues related to the differences. These assets are recognized for ratemaking purposes on a cash or flow-through basis and will be recovered in rates as they reverse. Postretirement benefits include the difference between contributions and deferred pension expense and the underfunded status of the pension plans. The underfunded status represents the difference between the projected benefit obligation and the fair market value of the assets. This asset is expected to be recovered in future years as additional contributions are made or markets continue to generate positive returns. The recovery period is dependent on contributions made to the plans, plan asset performance and the discount rate used to value the obligations. The period is estimated at between 5 and 10 years. The Company uses regulatory accounting treatment to defer the mark-to-market unrealized gains and losses on its interest rate swap to reflect that the gain or loss is included in the ratemaking formula when the transaction actually settles. The value of the swap as of the balance sheet date is recorded as part of other deferred credits. Realized gains or losses on the swap will be recorded as interest expense in the statement of income over its remaining term of 10 years. Utility plant retirement costs represents costs already incurred for the removal of assets, which are expected to be recovered over a five-year period in rates, through depreciation expense. The Company was granted approval by the PPUC to modify its tariff to replace lead customer-owned service lines that are discovered when the Company replaces its lead service lines over the remaining three years, and to include the cost of the annual replacement of up to 400 lead customer-owned service lines whenever they are discovered, regardless of the material used for the company-owned service line over nine years. The tariff modification allows the Company to replace customer-owned service lines at its own initial cost and record the costs as a regulatory asset to be recovered in future base rates to customers. The recovery period was established in the most recent rate order at four years beginning March 1, 2019. The recovery period for the customer-owned lead service line replacements completed subsequent to the most recent rate order will begin after the next rate order. Service life study expenses are deferred and amortized over their remaining life of three years. Rate case filing expenses are deferred and amortized over their remaining life of two years. Pursuant to the Tax Cuts and Jobs Act of 2017, or 2017 Tax Act, customers’ advances for construction and contributions in aid of construction are considered taxable income. The Company’s tariff allows the Company to record these income taxes for inclusion in rate base. This asset is recognized for ratemaking purposes on a cash or flow-through basis and will be recovered in rates as it reverses. Under normalization rules applicable to public utility property included in the 2017 Tax Act, the excess accumulated deferred income taxes on accelerated depreciation from lowering of the enacted federal statutory corporate tax rate is recorded as a regulatory liability. The benefit will be given back to customers in rates over the remaining regulatory life of the property. The regulatory liability for income taxes includes deferred taxes related to excess accumulated deferred income taxes on accelerated depreciation, other postretirement benefits, customers’ advances for construction and contributions in aid of construction, and bad debts, as well as deferred investment tax credits. These liabilities will be given back to customers in rates, as tax deductions occur over the next 1 to 50 years. The regulatory liability for the Internal Revenue Service, or IRS, tangible property regulations, or TPR, catch-up deduction represents the tax benefits realized on the Company’s 2014 income tax return for qualifying capital expenditures made prior to 2014. The recovery period was established in the most recent rate order at 15 years beginning March 1, 2019. Pursuant to a rate order approved by the PPUC, the Company has agreed to return the 2018 income tax savings pursuant to the 2017 Tax Act, the associated tax gross-up, and the excess accumulated deferred income taxes on accelerated depreciation to customers as a reconcilable negative surcharge on bills. The Company began giving back the liability over one year beginning March 1, 2019.
Other Assets	Other Assets Other assets consist mainly of the cash value of life insurance policies held as an investment by the Company for reimbursement of costs and benefits associated with its supplemental retirement and deferred compensation programs.
Deferred Debt Expense	Deferred Debt Expense Deferred debt expense is amortized on a straight-line basis over the term of the related debt and is presented on the balance sheet as a direct reduction from long-term debt.
Customers' Advances for Construction	Customers' Advances for Construction Customer advances are cash payments from developers, municipalities, customers or builders for construction of utility plant, and are refundable upon completion of construction, as operating revenues are earned. If the Company loans funds for construction to the customer, the refund amount is credited to the note receivable rather than paid out in cash. After all refunds to which the customer is entitled are made, any remaining balance is transferred to contributions in aid of construction.
Contributions in Aid of Construction	Contributions in Aid of Construction Contributions in Aid of Construction is composed of (i) direct, non-refundable contributions from developers, customers or builders for construction of water infrastructure and (ii) customer advances that have become non-refundable. Contributions in aid of construction are deducted from the Company’s rate base, and therefore, no return is earned on property financed with contributions. The PPUC requires that contributions received remain on the Company’s balance sheets indefinitely as a long-term liability.
Interest Rate Swap Agreement	Interest Rate Swap Agreement The Company is exposed to certain risks relating to its ongoing business operations. The primary risk managed by using derivative instruments is interest rate risk. The Company utilizes an interest rate swap agreement to convert its variable-rate debt to a fixed rate. Interest rate swaps are contracts in which a series of interest rate cash flows are exchanged over a prescribed period. The notional amount on which the interest payments are based is not exchanged. The Company has designated the interest rate swap agreement as a cash flow hedge, classified as a financial derivative used for non-trading activities. The accounting standards regarding accounting for derivatives and hedging activities require companies to recognize all derivative instruments as either assets or liabilities at fair value on the balance sheets. In accordance with the standards, the interest rate swap is recorded on the balance sheets in other deferred credits at fair value. The Company uses regulatory accounting treatment rather than hedge accounting to defer the unrealized gains and losses on its interest rate swap. These unrealized gains and losses are recorded as a regulatory asset. Based on current ratemaking treatment, the Company expects the gains and losses to be recognized in rates and in interest expense as the swap settlements occur. Swap settlements are recorded in the income statement with the hedged item as interest expense. Swap settlements resulted in the reclassification from regulatory assets to interest expense of $221 in 2019 and $236 in 2018. The overall swap result was a (gain) loss of $649 in 2019 and $(137) in 2018. During the twelve months ending December 31, 2020, the Company expects to reclassify $268 (before tax) from regulatory assets to interest expense. The interest rate swap will expire on October 1, 2029.
Stock-Based Compensation	Stock-Based Compensation The Company records compensation expense in the financial statements for stock-based awards based on the grant date fair value of those awards. Stock-based compensation expense is recognized over the requisite service periods of the awards on a straight-line basis, which is generally commensurate with the vesting term. Forfeitures are recognized as they occur.
Income Taxes	Income Taxes Certain income and expense items are accounted for in different time periods for financial reporting than for income tax reporting purposes. Deferred income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. To the extent such income taxes increase or decrease future rates, an offsetting regulatory asset or liability has been recorded. Investment tax credits have been deferred and are being amortized to income over the average estimated service lives of the related assets. As of December 31, 2019 and 2018, deferred investment tax credits amounted to $539 and $578, respectively. The Company filed for a change in accounting method under the IRS TPR effective in 2014. Under the change in accounting method, the Company is permitted to deduct the costs of certain asset improvements that were previously being capitalized and depreciated for tax purposes as an expense on its income tax return. The Company was permitted to make this deduction for prior years (the “catch-up deduction”) and each year going forward, beginning with 2014 (the “ongoing deduction”). After receiving approval from the PPUC in its most recent rate order, the Company began to recognize the catch-up deduction, recorded as a regulatory liability, over 15 years beginning March 1, 2019. The ongoing deduction results in a reduction in the effective income tax rate, a net reduction in income tax expense, and a reduction in the amount of income taxes currently payable. The catch-up deduction resulted in a decrease in current income taxes payable and an increase to regulatory liabilities. Both the ongoing and catch-up deductions resulted in increases to deferred tax liabilities and regulatory assets representing the appropriate book and tax basis difference on capital additions. The 2017 Tax Act, among other things, reduces the federal statutory corporate tax rate for tax years beginning in 2018 from 34% to 21%, eliminates certain deductions, and eliminates bonus depreciation on qualified water and wastewater property. This resulted in the remeasurement of the federal portion of the Company’s deferred taxes as of December 31, 2017 to the 21% rate. The effect was recognized in income for the year ended December 31, 2017 for all deferred tax assets and liabilities except accelerated depreciation. Under normalization rules applicable to public utility property included in the 2017 Tax Act, the excess accumulated deferred income taxes on accelerated depreciation is recorded as a regulatory liability. The regulatory liability is a temporary difference so a deferred tax asset is recorded including the gross-up of revenue necessary to return, in rates, the effect of the temporary difference.
Allowance for Funds Used During Construction	Allowance for Funds Used During Construction Allowance for funds used during construction (AFUDC) represents the estimated cost of funds used for construction purposes during the period of construction. These costs are reflected as non-cash income during the construction period and as an addition to the cost of plant constructed. AFUDC includes the net cost of borrowed funds and a rate of return on other funds. The PPUC approved rate of 10.04% was applied for 2019 and 2018. AFUDC is recovered through water and wastewater rates as utility plant is depreciated.
Use of Estimates in the Preparation of Financial Statements	Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Impact of Recent Accounting Pronouncements	Impact of Recent Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842)

Revenue (Policies)

Revenue (Policies)	12 Months Ended
Revenue (Policies)	Dec. 31, 2019
Revenue [Abstract]
Revenue	Utility Service The Company provides utility service as a distinct and single performance obligation to each of its water and wastewater customers. The transaction price is detailed in the tariff pursuant to an order by the PPUC and made publicly available. There is no variable consideration and no free service, special rates, or subnormal charges to any customer. Due to the fact that the contract includes a single performance obligation, no judgment is required to allocate the transaction price. The performance obligation is satisfied over time through the continuous provision of utility service through a stand-ready obligation to perform and the transfer of water or the collection of wastewater through a series of distinct transactions that are identical in nature and have the same pattern of transfer to the customer. The Company uses an output method to recognize the utility service revenue over time. The stand-ready obligation is recognized through the passage of time in the form of a fixed charge and the transfer of water or the collection of wastewater is recognized at a per unit rate based on the actual or estimated flow through the meter. Each customer is invoiced every month and the invoice is due within twenty days. The utility service has no returns or warranties associated with it. No revenue is recognized from performance obligations satisfied in prior periods and no performance obligations remain unsatisfied as of the end of the reporting period. A contract asset for unbilled revenue is recognized for the passage of time and the actual or estimated usage from the latest meter reading to the end of the accounting period. The methodology is standardized and consistently applied to reduce bias and the need for judgment. Billing and Revenue Collection Service The Company provides billing and revenue collection service as distinct performance obligations to three municipalities within the service territory of the Company. The municipalities provide wastewater service to their residents and the Company acts as the billing and revenue collection agent for the municipalities. The transaction price is a fixed amount per bill prepared as established in the contract. There is no variable consideration. Due to the fact that both the billing performance obligation and the revenue collection performance obligation are materially complete by the end of the reporting period, the Company does not allocate the transaction price between the two performance obligations. The performance obligations are satisfied at a point in time when the bills are sent as the municipalities receive all the benefits and bears all of the risk of non-collection at that time. Each municipality is invoiced when the bills are complete and the invoice is due within thirty days. The billing and revenue collection service has no returns or warranties associated with it. No revenue is recognized from performance obligations satisfied in prior periods and no performance obligations remain unsatisfied as of the end of the reporting period. Collection Service The Company provides collection service as a distinct and single performance obligation to several municipalities within the service territory of the Company. The municipalities provide wastewater service to their residents. If those residents are delinquent in paying for their wastewater service, the municipalities request that the Company post for and shut off the supply of water to the premises of those residents. When the resident is no longer delinquent, the Company will restore water service to the premises. The transaction price for each posting, each shut off, and each restoration is a fixed amount as established in the contract. There is no variable consideration. Due to the fact that the contract includes a single performance obligation, no judgment is required to allocate the transaction price. The performance obligation is satisfied at a point in time when the posting, shut off, or restoration is completed as the municipalities receive all the benefits in the form of payment or no longer providing wastewater service. Each municipality is invoiced periodically for the posting, shut offs, and restorations that have been completed since the last billing and the invoice is due within thirty days. The collection service has no returns or warranties associated with it. No revenue is recognized from performance obligations satisfied in prior periods and no performance obligations remain unsatisfied as of the end of the reporting period. A contract asset for unbilled revenue is recognized for postings, shut offs, and restorations that have been completed from the last billing to the end of the accounting period. Service Line Protection Plan The Company provides service line protection as a distinct and single performance obligation to current water customers that choose to participate. The transaction price is detailed in the plan’s terms and conditions and made publicly available. There is no variable consideration. Due to the fact that the contract includes a single performance obligation, no judgment is required to allocate the transaction price. The performance obligation is satisfied over time through the continuous provision of service line protection through a stand-ready obligation to perform. The Company uses an output method to recognize the service line protection revenue over time. The stand-ready obligation is recognized through the passage of time. A customer has a choice to prepay for an entire year or to pay in advance each month. The service line protection plan has no returns or extended warranties associated with it. No revenue is recognized from performance obligations satisfied in prior periods and no material performance obligations remain unsatisfied as of the end of the reporting period.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
Significant Accounting Policies (Tables)	Dec. 31, 2019
Significant Accounting Policies [Abstract]
Utility Plant	The following remaining lives are used for financial reporting purposes: December 31 Approximate range Utility Plant Asset Category 2019 2018 of remaining lives Mains and accessories $ 200,954 $ 190,679 11 – 86 years Services, meters and hydrants 77,501 74,178 17 – 51 years Operations structures, reservoirs and water tanks 63,530 61,868 10 – 58 years Pumping and treatment equipment 33,124 32,575 7 – 30 years Office, transportation and operating equipment 14,464 13,531 3 – 23 years Land and other non-depreciable assets 3,393 3,202 – Utility plant in service 392,966 376,033 Construction work in progress 8,417 4,751 – Total Utility Plant $ 401,383 $ 380,784
Regulatory Assets and Liabilities	Regulatory assets and liabilities are comprised of the following: December 31 Remaining Recovery 2019 2018 Periods Assets Income taxes $ 24,405 $ 21,432 Various Postretirement benefits 365 3,071 5 – 10 years Unrealized swap losses 2,227 1,799 1 – 10 years Utility plant retirement costs 5,012 4,841 5 years Customer-owned lead service line replacements 944 304 Various Income taxes on customers' advances for construction and contributions in aid of construction 998 577 Various Service life study expenses 13 18 3 years Rate case filing expenses 225 311 2 years $ 34,189 $ 32,353 Liabilities Excess accumulated deferred income taxes on accelerated depreciation $ 14,008 $ 14,184 Various Income taxes 7,494 6,979 Various IRS TPR catch-up deduction 3,671 3,887 14 years Revenue reduction for tax rate change 226 1,764 1 year $ 25,399 $ 26,814

Accounts Receivable and Contr_2

Accounts Receivable and Contract Assets (Tables)	12 Months Ended
Accounts Receivable and Contract Assets (Tables)	Dec. 31, 2019
Accounts Receivable and Contract Assets [Abstract]
Accounts Receivable and Contract Assets	Accounts receivable and contract assets are summarized in the following table: As of As of Dec. 31, 2019 Dec. 31, 2018 Change Accounts receivable – customers $ 4,574 $ 4,731 $ (157 ) Other receivables 152 385 (233 ) 4,726 5,116 (390 ) Less: allowance for doubtful accounts (305 ) (305 ) – Accounts receivable, net $ 4,421 $ 4,811 $ (390 ) Unbilled revenue $ 2,276 $ 2,427 $ (151 )

Note Receivable and Customers_2

Note Receivable and Customers' Advances for Construction (Tables)	12 Months Ended
	Dec. 31, 2019
Note Receivable and Customers' Advances for Construction [Abstract]
Amounts Related to Water District Projects	Included in the accompanying balance sheets at December 31, 2019 and 2018 were the following amounts related to this project. 2019 2018 Note receivable, including interest $ 255 $ 255 Customers' advances for construction 303 305

Common Stock and Earnings Per_2

Common Stock and Earnings Per Share (Tables)	12 Months Ended
Common Stock and Earnings Per Share (Tables)	Dec. 31, 2019
Common Stock and Earnings Per Share [Abstract]
Shares Used in Computing Basic and Diluted Earnings per Share	The following table summarizes the shares used in computing basic and diluted net income per share: 2019 2018 Weighted average common shares, basic 12,964,080 12,903,568 Effect of dilutive securities: Employee stock-based compensation 2,212 268 Weighted average common shares, diluted 12,966,292 12,903,836

Long-Term Debt and Short-Term_2

Long-Term Debt and Short-Term Borrowings (Tables)	12 Months Ended
Long-Term Debt and Short-Term Borrowings (Tables)	Dec. 31, 2019
Long-Term Debt and Short-Term Borrowings [Abstract]
Long-Term Debt	Long-term debt as of December 31, 2019 and 2018 is summarized in the following table: 2019 2018 10.17% Senior Notes, Series A, due 2019 $ – $ 6,000 9.60% Senior Notes, Series B, due 2019 – 5,000 1.00% Pennvest Note, due 2019 – 30 10.05% Senior Notes, Series C, due 2020 6,500 6,500 8.43% Senior Notes, Series D, due 2022 7,500 7,500 Variable Rate Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds, Series 2008A, due 2029 12,000 12,000 4.75% York County Industrial Development Authority Revenue Bonds, Series 2006, due 2036 – 10,500 3.00% Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds, Series A of 2019, due 2036 10,500 – 4.50% Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds, Series 2014, due 2038 – 14,870 3.10% Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds, Series B of 2019, due 2038 14,870 – 5.00% Monthly Senior Notes, Series 2010A, due 2040 – 15,000 3.23% Senior Notes, due 2040 15,000 – 4.00% - 4.50% York County Industrial Development Authority Exempt Facilities Revenue Bonds, Series 2015, due 2029 - 2045 10,000 10,000 4.54% Senior Notes, due 2049 20,000 – Committed Lines of Credit, due 2021 7,672 8,508 Total long-term debt 104,042 95,908 Less discount on issuance of long-term debt (192 ) (204 ) Less unamortized debt issuance costs (2,815 ) (2,346 ) Less current maturities (6,500 ) (30 ) Long-term portion $ 94,535 $ 93,328
Payments Due by Year	Payments due by year as of December 31, 2019: 2020 2021 2022 2023 2024 $ 6,500 $ 19,672 $ 7,500 $ – $ –

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
Fair Value of Financial Instruments (Tables)	Dec. 31, 2019
Fair Value of Financial Instruments [Abstract]
Fair Value of Interest Rate Swap	The Company has recorded its interest rate swap liability at fair value in accordance with the standards. The liability is recorded under the caption “Other deferred credits” on the balance sheets. The table below illustrates the fair value of the interest rate swap as of the end of the reporting period. Description December 31, 2019 Fair Value Measurements at Reporting Date Using Significant Other Observable Inputs (Level 2) Interest Rate Swap $ 2,248 $ 2,248 Fair values are measured as the present value of all expected future cash flows based on the LIBOR-based swap yield curve as of the date of the valuation. These inputs to this calculation are deemed to be Level 2 inputs. The balance sheet carrying value reflects the Company's credit quality as of December 31, 2019. The rate used in discounting all prospective cash flows anticipated to be made under this swap reflects a representation of the yield to maturity for 30-year debt on utilities rated A- as of December 31, 2019. The use of the Company's credit quality resulted in a reduction in the swap liability of $59 as of December 31, 2019. The fair value of the swap reflecting the Company's credit quality as of December 31, 2018 is shown in the table below. Description December 31, 2018 Fair Value Measurements at Reporting Date Using Significant Other Observable Inputs (Level 2) Interest Rate Swap $ 1,815 $ 1,815

Revenue (Tables)

Revenue (Tables)	12 Months Ended
Revenue (Tables)	Dec. 31, 2019
Revenue [Abstract]
Revenues Disaggregated by Service and Customer Type	The following table shows the Company’s revenues disaggregated by service and customer type. 2019 2018 Water utility service: Residential $ 32,118 $ 30,348 Commercial and industrial 14,161 13,351 Fire protection 3,074 2,931 Wastewater utility service: Residential 1,291 933 Commercial and industrial 280 227 Billing and revenue collection services 70 64 Collection services 52 54 Other revenue 13 22 Total Revenue from Contracts with Customers 51,059 47,930 Rents from regulated property 519 507 Total Operating Revenue $ 51,578 $ 48,437

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
Employee Benefit Plans (Tables)	Dec. 31, 2019
Employee Benefit Plans [Abstract]
Obligations and Funded Status	The following table sets forth the plans' funded status as of December 31, 2019 and 2018. The measurement of assets and obligations of the plans is as of December 31, 2019 and 2018. Obligations and Funded Status 2019 2018 Change in Benefit Obligation Pension benefit obligation beginning of year $ 41,511 $ 44,636 Service cost 849 1,015 Interest cost 1,645 1,515 Actuarial (gain) loss 5,241 (4,140 ) Benefit payments (1,716 ) (1,515 ) Pension benefit obligation end of year 47,530 41,511 Change in Plan Assets Fair value of plan assets beginning of year 40,624 41,439 Actual return on plan assets 8,141 (1,600 ) Employer contributions 2,300 2,300 Benefits paid (1,716 ) (1,515 ) Fair value of plan assets end of year 49,349 40,624 Funded Status of Plans at End of Year $ 1,819 $ (887 )
Changes in Plan Assets and Benefit Obligations Recognized in Regulatory Assets	Changes in plan assets and benefit obligations recognized in regulatory assets are as follows: 2019 2018 Net gain (loss) arising during the period $ (167 ) $ 252 Recognized net actuarial loss (421 ) (406 ) Recognized prior service credit 13 13 Total changes in regulatory asset during the year $ (575 ) $ (141 )
Amounts Recognized in Regulatory Assets That Have Not Yet Been Recognized as Components of Net Periodic Benefit Cost	Amounts recognized in regulatory assets that have not yet been recognized as components of net periodic benefit cost consist of the following at December 31: 2019 2018 Net loss $ 8,154 $ 8,742 Prior service credit (76 ) (89 ) Regulatory asset $ 8,078 $ 8,653
Components of Net Periodic Benefit Cost	Components of net periodic benefit cost are as follows: 2019 2018 Service cost $ 849 $ 1,015 Interest cost 1,645 1,515 Expected return on plan assets (2,733 ) (2,793 ) Amortization of loss 421 406 Amortization of prior service credit (13 ) (13 ) Rate-regulated adjustment 2,131 2,170 Net periodic benefit cost $ 2,300 $ 2,300
Regulatory Assets to be Reclassified into Net Periodic Benefit Cost Over Next Fiscal Year	The estimated costs for the defined benefit pension plans relating to the December 31, 2019 balance sheet that will be amortized from regulatory assets into net periodic benefit cost over the next fiscal year are as follows: Net loss $ 353 Net prior service credit (13 ) 340
Benefit Payments Expected to be Paid	The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid in each of the next five years and the subsequent five years in the aggregate: 2020 2021 2022 2023 2024 2025 2029 $ 1,827 $ 1,891 $ 1,964 $ 2,138 $ 2,208 $ 11,830
Projected Benefit Obligation and Fair Value of Plan Assets	The following tables show the projected benefit obligation, the accumulated benefit obligation and the fair value of plan assets as of December 31: 2019 2018 Projected benefit obligation $ 47,530 $ 41,511 Fair value of plan assets 49,349 40,624
Accumulated Benefit Obligation and Fair Value of Plan Assets	2019 2018 Accumulated benefit obligation $ 44,587 $ 39,100 Fair value of plan assets 49,349 40,624
Weighted-Average Assumptions Used	Weighted-average assumptions used to determine benefit obligations at December 31: 2019 2018 Discount rate 3.10% 4.10% Rate of compensation increase 2.50% – 3.00% 2.50% – 3.00% Weighted-average assumptions used to determine net periodic benefit cost for years ended December 31: 2019 2018 Discount rate 4.10% 3.50% Expected long-term return on plan assets 6.50% 6.75% Rate of compensation increase 2.50% – 3.00% 2.50% – 3.00%
Fair Values of Pension Plan Assets	The fair values of the Company's pension plan assets at December 31, 2019 and 2018 by asset category and fair value hierarchy level are as follows. The majority of the valuations are based on quoted prices on active markets (Level 1), with the remaining valuations based on broker/dealer quotes, active market makers, models, and yield curves (Level 2). Total Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Asset Category 2019 2018 2019 2018 2019 2018 Cash and Money Market Funds (a) $ 682 $ 1,498 $ 682 $ 1,498 $ – $ – Equity Securities: Common Equity Securities (b) 662 512 662 512 – – Equity Mutual Funds (c) 29,677 23,637 29,677 23,637 – – Fixed Income Securities: U.S. Treasury Obligations 615 591 – – 615 591 Corporate and Foreign Bonds (d) 6,078 5,315 – – 6,078 5,315 Fixed Income Mutual Funds (e) 11,635 9,071 11,635 9,071 – – Total Plan Assets $ 49,349 $ 40,624 $ 42,656 $ 34,718 $ 6,693 $ 5,906 (a) The portfolios are designed to keep up to one year of distributions in immediately available funds. (b) This category includes investments in U.S. common stocks and foreign stocks trading in the U.S. widely distributed among consumer discretionary, consumer staples, healthcare, information technology, financial services, telecommunications, industrials, real estate, materials, and energy. The individual stocks are primarily large cap stocks which track with the S&P 500. (c) This category currently includes a majority of investments in closed-end mutual funds as well as domestic equity mutual funds and international mutual funds which give the portfolio exposure to mid and large cap index funds as well as international diversified index funds. (d) This category currently includes only U.S. corporate bonds and notes widely distributed among consumer discretionary, consumer staples, healthcare, information technology, energy, transportation, and financial services. (e) This category includes fixed income investments in mutual funds which include government, corporate and mortgage securities of both the U.S. and other countries. The mortgage-backed securities and non-U.S. corporate and sovereign investments add further diversity to the fixed income portion of the portfolio.

Stock Based Compensation (Table

Stock Based Compensation (Tables)	12 Months Ended
Stock Based Compensation (Tables)	Dec. 31, 2019
Stock-Based Compensation [Abstract]
Restricted Stock	The following table summarizes the stock grant amounts and activity for the years ended December 31, 2018 and 2019. Number of Shares Grant Date Weighted Average Fair Value Nonvested at beginning of the year 2018 1,127 $37.76 Granted 3,743 $32.70 Vested (1,790 ) $33.90 Forfeited – – Nonvested at end of the year 2018 3,080 $33.85 Granted 6,963 $33.61 Vested (2,701 ) $33.99 Forfeited – – Nonvested at end of the year 2019 7,342 $33.57

Taxes Other than Income Taxes (

Taxes Other than Income Taxes (Tables)	12 Months Ended
Taxes Other than Income Taxes (Tables)	Dec. 31, 2019
Taxes Other than Income Taxes [Abstract]
Components of Taxes Other than Income Taxes	The following table provides the components of taxes other than income taxes: 2019 2018 Regulatory Assessment $ 285 $ 261 Property 348 345 Payroll, net of amounts capitalized 564 538 Other 3 1 Total taxes other than income taxes $ 1,200 $ 1,145

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2019
Income Taxes [Abstract]
Provisions for Income Taxes	The provisions for income taxes consist of: 2019 2018 Federal current $ 1,148 $ 1,715 State current 451 718 Federal deferred 475 216 State deferred 205 (119 ) Federal investment tax credit, net of current utilization (39 ) (39 ) Total income taxes $ 2,240 $ 2,491
Reconciliation of Statutory Federal Tax Provision to Total Provision	A reconciliation of the statutory Federal tax provision to the total provision follows: 2019 2018 Statutory Federal tax provision $ 3,495 $ 3,332 State income taxes, net of Federal benefit 574 471 IRS TPR deduction (1,642 ) (1,307 ) Tax-exempt interest (25 ) (22 ) Amortization of investment tax credit (39 ) (39 ) Cash value of life insurance 6 (13 ) Amortization of excess accumulated deferred income taxes on accelerated depreciation (149 ) – Other, net 20 69 Total income taxes $ 2,240 $ 2,491
Deferred Tax Assets and Liabilities	The tax effects of temporary differences between book and tax balances that give rise to significant portions of the deferred tax assets and deferred tax liabilities as of December 31, 2019 and 2018 are summarized in the following table: 2019 2018 Deferred tax assets: Reserve for doubtful accounts $ 88 $ 88 Compensated absences 148 147 Deferred compensation 1,276 1,143 Excess accumulated deferred income taxes on accelerated depreciation 4,047 4,098 Deferred taxes associated with the gross-up of revenues necessary to return, in rates, the effect of temporary differences 2,104 2,077 Customers' advances for construction and contributions in aid of construction 998 577 Revenue reduction for tax rate change 7 333 Pensions – 256 Other costs deducted for book, not for tax 69 40 Total deferred tax assets 8,737 8,759 Deferred tax liabilities: Accelerated depreciation 28,891 28,479 Basis differences from IRS TPR 11,311 9,367 Investment tax credit 384 411 Deferred taxes associated with the gross-up of revenues necessary to recover, in rates, the effect of temporary differences 6,987 6,124 Pensions 525 – Tax effect of pension regulatory asset 106 887 Unamortized debt issuance costs 531 197 Other costs deducted for tax, not for book 428 256 Total deferred tax liabilities 49,163 45,721 Net deferred tax liability $ 40,426 $ 36,962

Significant Accounting Polici_4

Significant Accounting Policies, Utility Plant and Depreciation (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)System	Dec. 31, 2018USD ($)
Significant Accounting Policies [Abstract]
Number of wastewater collection systems operated \| System	2
Number of wastewater collection and treatment systems operated \| System	2
Utility Plant and Depreciation [Abstract]
Utility plant acquisition adjustments	$ 3,318	$ 3,108
Amortization of utility plant acquisition adjustments	61	58
Utility plant	$ 401,383	$ 380,784
Effective rate of depreciation	2.29%	2.21%
Mains and Accessories [Member]
Utility Plant and Depreciation [Abstract]
Utility plant	$ 200,954	$ 190,679
Mains and Accessories [Member] \| Minimum [Member]
Utility Plant and Depreciation [Abstract]
Remaining life	11 years
Mains and Accessories [Member] \| Maximum [Member]
Utility Plant and Depreciation [Abstract]
Remaining life	86 years
Services, Meters and Hydrants [Member]
Utility Plant and Depreciation [Abstract]
Utility plant	$ 77,501	74,178
Services, Meters and Hydrants [Member] \| Minimum [Member]
Utility Plant and Depreciation [Abstract]
Remaining life	17 years
Services, Meters and Hydrants [Member] \| Maximum [Member]
Utility Plant and Depreciation [Abstract]
Remaining life	51 years
Operations Structures, Reservoirs and Water Tanks [Member]
Utility Plant and Depreciation [Abstract]
Utility plant	$ 63,530	61,868
Operations Structures, Reservoirs and Water Tanks [Member] \| Minimum [Member]
Utility Plant and Depreciation [Abstract]
Remaining life	10 years
Operations Structures, Reservoirs and Water Tanks [Member] \| Maximum [Member]
Utility Plant and Depreciation [Abstract]
Remaining life	58 years
Pumping and Treatment Equipment [Member]
Utility Plant and Depreciation [Abstract]
Utility plant	$ 33,124	32,575
Pumping and Treatment Equipment [Member] \| Minimum [Member]
Utility Plant and Depreciation [Abstract]
Remaining life	7 years
Pumping and Treatment Equipment [Member] \| Maximum [Member]
Utility Plant and Depreciation [Abstract]
Remaining life	30 years
Office, Transportation and Operating Equipment [Member]
Utility Plant and Depreciation [Abstract]
Utility plant	$ 14,464	13,531
Office, Transportation and Operating Equipment [Member] \| Minimum [Member]
Utility Plant and Depreciation [Abstract]
Remaining life	3 years
Office, Transportation and Operating Equipment [Member] \| Maximum [Member]
Utility Plant and Depreciation [Abstract]
Remaining life	23 years
Land and Other Non-Depreciable Assets [Member]
Utility Plant and Depreciation [Abstract]
Utility plant	$ 3,393	3,202
Utility Plant in Service [Member]
Utility Plant and Depreciation [Abstract]
Utility plant	392,966	376,033
Construction Work in Progress [Member]
Utility Plant and Depreciation [Abstract]
Utility plant	$ 8,417	$ 4,751

Significant Accounting Polici_5

Significant Accounting Policies, Regulatory Assets and Liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)ServiceLine	Dec. 31, 2018USD ($)
Assets [Abstract]
Regulatory assets	$ 34,189	$ 32,353
Liabilities [Abstract]
Regulatory liabilities	25,399	26,814
Excess Accumulated Deferred Income Taxes on Accelerated Depreciation [Member]
Liabilities [Abstract]
Regulatory liabilities	14,008	14,184
Income Taxes [Member]
Liabilities [Abstract]
Regulatory liabilities	$ 7,494	6,979
Income Taxes [Member] \| Minimum [Member]
Liabilities [Abstract]
Remaining recovery period	1 year
Income Taxes [Member] \| Maximum [Member]
Liabilities [Abstract]
Remaining recovery period	50 years
IRS TPR Catch-Up Deduction [Member]
Liabilities [Abstract]
Regulatory liabilities	$ 3,671	3,887
Remaining recovery period	14 years
Revenue Reduction For Tax Rate Change [Member]
Liabilities [Abstract]
Regulatory liabilities	$ 226	1,764
Remaining recovery period	1 year
Term for negative surcharge on bills to customers	1 year
Income Taxes [Member]
Assets [Abstract]
Regulatory assets	$ 24,405	21,432
Postretirement Benefits [Member]
Assets [Abstract]
Regulatory assets	$ 365	3,071
Postretirement Benefits [Member] \| Minimum [Member]
Assets [Abstract]
Remaining recovery period	5 years
Postretirement Benefits [Member] \| Maximum [Member]
Assets [Abstract]
Remaining recovery period	10 years
Unrealized Swap Losses [Member]
Assets [Abstract]
Regulatory assets	$ 2,227	1,799
Unrealized Swap Losses [Member] \| Minimum [Member]
Assets [Abstract]
Remaining recovery period	1 year
Unrealized Swap Losses [Member] \| Maximum [Member]
Assets [Abstract]
Remaining recovery period	10 years
Utility Plant Retirement Costs [Member]
Assets [Abstract]
Regulatory assets	$ 5,012	4,841
Remaining recovery period	5 years
Customer-Owned Lead Service Line Replacements [Member]
Assets [Abstract]
Regulatory assets	$ 944	304
Remaining recovery period	4 years
Term of tariff modification to replace customer-owned lead service lines connected to company-owned lead service lines	3 years
Number of lead customer-owned service lines to be replaced annually \| ServiceLine	400
Term of tariff modification to replace customer-owned lead service lines	9 years
Income Taxes on Customers' Advances for Construction and Contributions in Aid of Construction [Member]
Assets [Abstract]
Regulatory assets	$ 998	577
Service Life Study Expenses [Member]
Assets [Abstract]
Regulatory assets	$ 13	18
Remaining recovery period	3 years
Rate Case Filing Expenses [Member]
Assets [Abstract]
Regulatory assets	$ 225	$ 311
Remaining recovery period	2 years

Significant Accounting Polici_6

Significant Accounting Policies, Interest Rate Swap Agreement (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Interest Rate Swap Agreement [Abstract]
Interest rate swap settlements reclassified from regulatory assets to interest expense	$ 221	$ 236
Overall interest rate swap (gain) loss	649	$ (137)
Interest rate swap settlements to be reclassified during the next 12 months	$ 268
Interest rate swap expiration date	Oct. 1, 2029

Significant Accounting Polici_7

Significant Accounting Policies, Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Abstract]
Deferred investment tax credits	$ 539	$ 578
Federal corporate tax rate	21.00%	21.00%	34.00%
IRS TPR Catch-Up Deduction [Member]
Income Taxes [Abstract]
Approved amortization period	15 years

Significant Accounting Polici_8

Significant Accounting Policies, Allowance for Funds Used During Construction (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Allowance for Funds Used During Construction [Abstract]
PPUC approved rate for AFUDC	10.04%	10.04%

Acquisitions (Details)

Acquisitions (Details) $ in Thousands	Aug. 29, 2019USD ($)Customer	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Acquisitions [Abstract]
Purchase price		$ 2,112	$ 0
Acquisition adjustment		$ (3,318)	$ (3,108)
Wastewater Collection Assets of Jacobus Borough Sewer Authority [Member]
Acquisitions [Abstract]
Number of customers acquired \| Customer	700
Purchase price	$ 2,112
Acquisition adjustment	$ (271)

Accounts Receivable and Contr_3

Accounts Receivable and Contract Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable and Contract Assets [Abstract]
Accounts receivable - customers	$ 4,574	$ 4,731
Other receivables	152	385
Accounts receivable	4,726	5,116
Less: allowance for doubtful accounts	(305)	(305)
Accounts receivable, net	4,421	4,811
Unbilled revenue	2,276	$ 2,427
Change in accounts receivable - customers	(157)
Change in other receivables	(233)
Change in accounts receivable	(390)
Change in allowance for doubtful accounts	0
Change in accounts receivable, net	(390)
Change in unbilled revenue	$ (151)

Note Receivable and Customers_3

Note Receivable and Customers' Advances for Construction (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)Municipality	Dec. 31, 2018USD ($)
Note Receivable and Customers' Advances for Construction [Abstract]
Number of municipalities with agreements to extend water service \| Municipality	1
Interest income on note receivable	$ 121	$ 105
Interest rate on note outstanding	7.50%
Amounts Related to Water District Projects Included in Balance Sheet [Abstract]
Note receivable, including interest	$ 255	255
Customers' advances for construction	303	305
Other customers' advances for construction	$ 7,541	$ 6,544

Common Stock and Earnings Per_3

Common Stock and Earnings Per Share (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Nov. 08, 2019	Mar. 11, 2013
Common Stock and Earnings Per Share [Abstract]
Net income	$ 14,402	$ 13,376
Shares Used in Computing Basic and Diluted Earnings per Share [Abstract]
Weighted average common shares, basic (in shares)	12,964,080	12,903,568
Effect of dilutive securities [Abstract]
Employee stock-based compensation (in shares)	2,212	268
Weighted average common shares, diluted (in shares)	12,966,292	12,903,836
Stock Repurchase Program [Abstract]
Number of shares authorized to be repurchased under the stock repurchase program (in shares)				1,200,000
Number of shares repurchased and retired under the stock repurchase program (in shares)	0	0
Number of remaining shares authorized to be repurchased under the stock repurchase program (in shares)	618,004
Employee Stock Purchase Plan [Member]
Common Stock [Abstract]
Minimum period full-time employees must be employed to purchase shares	90 days
Maximum percentage of gross compensation allowed to purchase shares	10.00%
Purchase price as a percentage of fair market value of common stock	95.00%
Number of shares issued (in shares)	3,914	5,187
Number of authorized shares remaining to be issued (in shares)	61,725
Dividend Reinvestment and Direct Stock Purchase and Sale Plan [Member]
Common Stock [Abstract]
Number of shares authorized to be issued (in shares)			157,000
Number of shares authorized, unissued, and rolled over under plan (in shares)			344,379
Number of shares issued (in shares)	60,485	61,864
Number of authorized shares remaining to be issued (in shares)	475,889
Optional Dividend Reinvestment Portion of Plan [Member]
Common Stock [Abstract]
Purchase price as a percentage of fair market value of common stock	95.00%
Direct Stock Purchase Portion of Plan [Member]
Common Stock [Abstract]
Purchase price as a percentage of fair market value of common stock	100.00%

Long-Term Debt and Short-Term_3

Long-Term Debt and Short-Term Borrowings, Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Oct. 08, 2019	Oct. 01, 2019	Jan. 31, 2019	Dec. 31, 2018
Long-term Debt [Abstract]
Long-term debt	$ 104,042				$ 95,908
Less discount on issuance of long-term debt	(192)				(204)
Less unamortized debt issuance costs	(2,815)				(2,346)
Less current maturities	(6,500)				(30)
Long-term portion	94,535				93,328
10.17% Senior Notes, Series A, due 2019 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 0				6,000
Interest rate	10.17%			10.17%
9.60% Senior Notes, Series B, due 2019 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 0				5,000
Interest rate	9.60%			9.60%
1.00% Pennvest Note, due 2019 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 0				30
Interest rate	1.00%
10.05% Senior Notes, Series C, due 2020 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 6,500				6,500
Interest rate	10.05%
8.43% Senior Notes, Series D, due 2022 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 7,500				7,500
Interest rate	8.43%
Variable Rate Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds Series 2008A, due 2029 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 12,000				12,000
4.75% York County Industrial Development Authority Revenue Bonds, Series 2006, due 2036 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 0				10,500
Interest rate	4.75%	4.75%
3.00% PEDFA Exempt Facilities Revenue Refunding Bonds, Series A of 2019, due 2036 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 10,500				0
Interest rate	3.00%	3.00%
4.50% PEDFA Exempt Facilities Revenue Refunding Bonds, Series 2014, due 2038 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 0				14,870
Interest rate	4.50%	4.50%
3.10% PEDFA Exempt Facilities Revenue Refunding Bonds, Series B of 2019, due 2038 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 14,870				0
Interest rate	3.10%	3.10%
5.00% Monthly Senior Notes, Series 2010A, due 2040 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 0				15,000
Interest rate	5.00%		5.00%
3.23% Senior Notes, due 2040 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 15,000				0
Interest rate	3.23%		3.23%
4.00% - 4.50% York County Industrial Development Authority Exempt Facilities Revenue Bonds, Series 2015, due 2029 - 2045 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 10,000				10,000
4.00% - 4.50% York County Industrial Development Authority Exempt Facilities Revenue Bonds, Series 2015, due 2029 - 2045 [Member] \| Minimum [Member]
Long-term Debt [Abstract]
Interest rate	4.00%
4.00% - 4.50% York County Industrial Development Authority Exempt Facilities Revenue Bonds, Series 2015, due 2029 - 2045 [Member] \| Maximum [Member]
Long-term Debt [Abstract]
Interest rate	4.50%
4.54% Senior Notes, due 2049 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 20,000				0
Interest rate	4.54%			4.54%
Committed Line of Credit, due 2021 [Member]
Long-term Debt [Abstract]
Long-term debt	$ 7,672				$ 8,508

Long-Term Debt and Short-Term_4

Long-Term Debt and Short-Term Borrowings, Payments Due by Year (Details) $ in Thousands	Dec. 31, 2019USD ($)
Payments Due by Year [Abstract]
2020	$ 6,500
2021	19,672
2022	7,500
2023	0
2024	0
Variable Rate Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds Series 2008A, due 2029 [Member]
Payments Due by Year [Abstract]
2021	$ 12,000

Long-Term Debt and Short-Term_5

Long-Term Debt and Short-Term Borrowings, Fixed Rate Long-Term Debt (Details) - USD ($) $ in Thousands	Oct. 08, 2019	Oct. 01, 2019	Jan. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
4.50% PEDFA Exempt Facilities Revenue Refunding Bonds, Series 2014, due 2038 [Member]
Long-Term Debt [Abstract]
Maximum amount that can be redeemed per individual interest per year				$ 25
Maximum amount that can be redeemed in the aggregate per year				300
Bonds redeemed that meet special provisions				$ 0	$ 0
Face value	$ 14,870
Interest rate	4.50%			4.50%
Maturity date				Nov. 1, 2038
10.17% Senior Notes, Series A, due 2019 [Member]
Long-Term Debt [Abstract]
Interest rate			10.17%	10.17%
Maturity date				Feb. 1, 2019
9.60% Senior Notes, Series B, due 2019 [Member]
Long-Term Debt [Abstract]
Interest rate			9.60%	9.60%
Maturity date				Feb. 1, 2019
4.54% Senior Notes, due 2049 [Member]
Long-Term Debt [Abstract]
Face value			$ 20,000
Interest rate			4.54%	4.54%
Maturity date				Jan. 31, 2049
Proceeds from debt, net of issuance costs			$ 19,820
10.17% Series A Senior Notes and 9.60% Series B Senior Notes [Member]
Long-Term Debt [Abstract]
Face value			$ 11,000
3.23% Senior Notes, due 2040 [Member]
Long-Term Debt [Abstract]
Face value		$ 15,000
Interest rate		3.23%		3.23%
Maturity date				Oct. 1, 2040
Proceeds from debt, net of issuance costs		$ 14,888
5.00% Monthly Senior Notes, Series 2010A, due 2040 [Member]
Long-Term Debt [Abstract]
Face value		$ 15,000
Interest rate		5.00%		5.00%
Maturity date				Oct. 1, 2040
3.00% PEDFA Exempt Facilities Revenue Refunding Bonds, Series A of 2019, due 2036 [Member]
Long-Term Debt [Abstract]
Face value	$ 10,500
Interest rate	3.00%			3.00%
Maturity date				Oct. 1, 2036
3.10% PEDFA Exempt Facilities Revenue Refunding Bonds, Series B of 2019, due 2038 [Member]
Long-Term Debt [Abstract]
Face value	$ 14,870
Interest rate	3.10%			3.10%
Maturity date				Nov. 1, 2038
Series A and Series B Bonds [Member]
Long-Term Debt [Abstract]
Proceeds from debt, net of issuance costs	$ 25,049
4.75% York County Industrial Development Authority Revenue Bonds, Series 2006, due 2036 [Member]
Long-Term Debt [Abstract]
Face value	$ 10,500
Interest rate	4.75%			4.75%
Maturity date				Oct. 1, 2036

Long-Term Debt and Short-Term_6

Long-Term Debt and Short-Term Borrowings, Variable Rate Long-Term Debt (Details) - Variable Rate Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds Series 2008A, due 2029 [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Variable Rate Long-Term Debt [Abstract]
Face value	$ 12,000
Maturity date	Oct. 1, 2029
Annual average variable interest rate	1.50%	1.46%
Variable interest rate at year end	1.78%	1.75%
Period in which to reimburse bank for purchase price of tendered bonds that have not been remarketed	14 months
Letter of Credit [Member]
Variable Rate Long-Term Debt [Abstract]
Expiration date	Jun. 30, 2021

Long-Term Debt and Short-Term_7

Long-Term Debt and Short-Term Borrowings, Interest Rate Swap Agreement (Details) - Interest Rate Swap [Member] - Variable Rate Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds Series 2008A, due 2029 [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Interest Rate Swap Agreement [Abstract]
Notional amount of swap	$ 12,000
Potential payment to counterparty	$ 2,307
Fixed interest rate	3.16%
Net payment rate on swap	1.84%	1.97%
Interest rate spread	0.75%	0.31%
Overall effective rate, including variable interest and swap payments	3.91%	3.47%
LIBOR [Member]
Interest Rate Swap Agreement [Abstract]
Percentage of variable interest rate	59.00%
Term of variable rate	1 month

Long-Term Debt and Short-Term_8

Long-Term Debt and Short-Term Borrowings, Line of Credit Borrowings (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)Bank	Dec. 31, 2018USD ($)
Line of Credit Facility [Abstract]
Borrowing capacity	$ 41,500
Number of banks in which unsecured line of credit maintained \| Bank	4
Average borrowings outstanding	$ 5,070	$ 7,206
Weighted average cost of borrowings	3.47%	3.20%
Weighted average interest rate at year end	2.92%	3.60%
Unsecured Line of Credit, First Note [Member]
Line of Credit Facility [Abstract]
Borrowing capacity	$ 13,000
Maturity period	2 years
Maturity date	May 31, 2021
Outstanding borrowings under line of credit	$ 3,672	$ 6,508
Unsecured Line of Credit, First Note [Member] \| LIBOR [Member]
Line of Credit Facility [Abstract]
Basis adjustment	1.20%
Unsecured Line of Credit, Second Note [Member]
Line of Credit Facility [Abstract]
Borrowing capacity	$ 11,000
Maturity date	May 31, 2021
Unsecured Line of Credit, Second Note [Member] \| LIBOR [Member]
Line of Credit Facility [Abstract]
Basis adjustment	1.25%
Unsecured Line of Credit, Third Note [Member]
Line of Credit Facility [Abstract]
Borrowing capacity	$ 7,500
Maturity date	Jun. 30, 2021
Outstanding borrowings under line of credit	$ 4,000	2,000
Unsecured Line of Credit, Third Note [Member] \| LIBOR [Member]
Line of Credit Facility [Abstract]
Basis adjustment	1.15%
Unsecured Line of Credit, Fourth Note [Member]
Line of Credit Facility [Abstract]
Borrowing capacity	$ 10,000
Maturity date	Sep. 30, 2020
Outstanding borrowings under line of credit	$ 0	$ 1,000
Unsecured Line of Credit, Fourth Note [Member] \| LIBOR [Member]
Line of Credit Facility [Abstract]
Basis adjustment	1.20%

Long-Term Debt and Short-Term_9

Long-Term Debt and Short-Term Borrowings, Debt Covenants and Restrictions (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Debt Covenants and Restrictions [Abstract]
Maximum borrowing percentage of utility plant	60.00%
Base amount added to annual net income to determine restriction on dividends and stock acquisition	$ 1,500
1.00% Pennvest Note, due 2019 [Member]
Debt Covenants and Restrictions [Abstract]
Amount of receivables pledged as collateral	$ 800

Fair Value of Financial Instr_3

Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Interest Rate Swap [Abstract]
Term of debt on utilities rated A- used to discount prospective cash flows	30 years
Reduction in the fair value of swap liability	$ 59
Fair Value Measurements [Abstract]
Customers' advances for construction	7,844	$ 6,849
Note receivable	255	255
Fair Value on a Recurring Basis [Member]
Interest Rate Swap [Abstract]
Interest rate swap	2,248	1,815
Fair Value on a Recurring Basis [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Interest Rate Swap [Abstract]
Interest rate swap	2,248	1,815
Carrying Amount [Member]
Fair Value, Financial Liabilities [Abstract]
Total long-term debt	104,042	95,908
Estimated Fair Value [Member]
Fair Value, Financial Liabilities [Abstract]
Total long-term debt	$ 115,000	$ 105,000

Commitments (Details)

Commitments (Details) $ in Thousands	12 Months Ended
Commitments (Details) $ in Thousands	Dec. 31, 2019USD ($)ServiceLine	Dec. 31, 2018USD ($)
Commitments [Abstract]
Percentage of employees under union contract	31.00%
Company-Owned Lead Service Lines [Member]
Commitments [Abstract]
Term to replace all remaining company-owned lead service lines	4 years
Costs incurred to replace company-owned lead service lines	$ 2,713	$ 2,341
Customer-Owned Lead Service Lines [Member]
Commitments [Abstract]
Number of lead customer-owned service lines to be replaced annually \| ServiceLine	400
Term of tariff modification to replace customer-owned lead service lines	9 years
Recovery period of regulatory asset	4 years
Costs for Customer-Owned Lead Service Line Replacements, Cost Incurred to Date Under Four-Year Tariff	$ 1,000	$ 304
Costs to be incurred to replace customer-owned lead service lines	1,300
Construction and Acquisition Expenditures [Member]
Capital Commitments [Abstract]
Commitment for 2020	29,500
Commitment for 2021	$ 27,000

Revenue (Details)

Revenue (Details) $ in Thousands	12 Months Ended
Revenue (Details) $ in Thousands	Dec. 31, 2019USD ($)Municipality	Dec. 31, 2018USD ($)
Revenue [Abstract]
Revenue from contracts with customers	$ 51,059	$ 47,930
Rents from regulated property	519	507
Total operating revenue	$ 51,578	48,437
Utility Service [Member]
Revenue [Abstract]
Number of days for customer to make payment after being invoiced	20 days
Water Utility Service [Member] \| Residential [Member]
Revenue [Abstract]
Revenue from contracts with customers	$ 32,118	30,348
Water Utility Service [Member] \| Commercial and Industrial [Member]
Revenue [Abstract]
Revenue from contracts with customers	14,161	13,351
Water Utility Service [Member] \| Fire Protection [Member]
Revenue [Abstract]
Revenue from contracts with customers	3,074	2,931
Wastewater Utility Service [Member] \| Residential [Member]
Revenue [Abstract]
Revenue from contracts with customers	1,291	933
Wastewater Utility Service [Member] \| Commercial and Industrial [Member]
Revenue [Abstract]
Revenue from contracts with customers	280	227
Billing and Revenue Collection Services [Member]
Revenue [Abstract]
Revenue from contracts with customers	$ 70	64
Number of municipalities within the service territory provided service \| Municipality	3
Number of days for customer to make payment after being invoiced	30 days
Collection Services [Member]
Revenue [Abstract]
Revenue from contracts with customers	$ 52	54
Number of days for customer to make payment after being invoiced	30 days
Other Revenue [Member]
Revenue [Abstract]
Revenue from contracts with customers	$ 13	$ 22

Rate Matters (Details)

Rate Matters (Details) - PPUC [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Rate Matters [Abstract]
Amount agreed to be returned to customers for effects of 2017 Tax Act	$ 2,117
Revenue recorded as regulatory liability for effects of 2017 Tax Act	(325)	$ (1,600)
Reclassification from excess accumulated deferred income taxes on accelerated depreciation	(27)	(164)
Negative surcharges returned to customers for effects of 2017 Tax Act	1,891
Rate Request Filed on May 30, 2018 [Member] \| Water [Member]
Rate Matters [Abstract]
Requested increase in annual revenue	6,399
Authorized dollar increase in annual revenues from the PPUC	3,361
Rate Request Filed on May 30, 2018 [Member] \| Wastewater [Member]
Rate Matters [Abstract]
Requested increase in annual revenue	289
Authorized dollar increase in annual revenues from the PPUC	289
DSIC [Member]
Rate Matters [Abstract]
Distribution system improvement charge revenue	$ 249	$ 1,971
DSIC [Member] \| Maximum [Member]
Rate Matters [Abstract]
Distribution system improvement charge percentage over base rate	5.00%
DSIC [Member] \| Minimum [Member]
Rate Matters [Abstract]
Distribution system improvement charge percentage over base rate	0.00%

Employee Benefit Plans, Changes

Employee Benefit Plans, Changes in Benefit Obligation and Plan Assets (Details) - Defined Benefit Pension Plans Combined [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Employee Benefit Plans [Abstract]
Maximum period of eligible service	30 years
Change in Benefit Obligation [Abstract]
Pension benefit obligation, beginning of year	$ 41,511	$ 44,636
Service cost	849	1,015
Interest cost	1,645	1,515
Actuarial (gain) loss	5,241	(4,140)
Benefit payments	(1,716)	(1,515)
Pension benefit obligation, end of year	47,530	41,511
Change in Plan Assets [Abstract]
Fair value of plan assets, beginning of year	40,624	41,439
Actual return on plan assets	8,141	(1,600)
Employer contributions	2,300	2,300
Benefits paid	(1,716)	(1,515)
Fair value of plan assets, end of year	49,349	40,624
Funded Status of Plans at end of year	$ 1,819	$ (887)
Change in discount rate	(1.00%)	0.60%
Threshold for amortization of gains and losses	10.00%
Changes in Plan Assets and Benefit Obligations Recognized in Regulatory Assets [Abstract]
Net gain (loss) arising during the period	$ (167)	$ 252
Recognized net actuarial loss	(421)	(406)
Recognized prior service credit	13	13
Total changes in regulatory asset during the year	(575)	(141)
Amounts Recognized in Regulatory Assets that Have Not Yet Been Recognized as Components of Net Periodic Benefit Cost [Abstract]
Net loss	8,154	8,742
Prior service credit	(76)	(89)
Regulatory asset	$ 8,078	$ 8,653

Employee Benefit Plans, Compone

Employee Benefit Plans, Components of Net Periodic Benefit Cost (Details) - Defined Benefit Pension Plans Combined [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Components of Net Periodic Benefit Cost [Abstract]
Service cost	$ 849	$ 1,015
Interest cost	1,645	1,515
Expected return on plan assets	(2,733)	(2,793)
Amortization of loss	421	406
Amortization of prior service credit	(13)	(13)
Rate-regulated adjustment	2,131	2,170
Net periodic benefit cost	2,300	$ 2,300
Change in defined benefit plan regulatory asset from pension contribution greater (less) than net periodic benefit cost	(2,131)
Amortization of Regulatory Assets to be Reclassified into Net Periodic Benefit Cost [Abstract]
Net loss	353
Net prior service credit	(13)
Total amortization of regulatory assets to be reclassified into net periodic benefit cost during the next fiscal year	$ 340

Employee Benefit Plans, Benefit

Employee Benefit Plans, Benefit Payments Expected to be Paid (Details) $ in Thousands	Dec. 31, 2019USD ($)
Estimated Future Employer Contributions [Abstract]
Estimated employer contributions in 2020	$ 2,300
Defined Benefit Pension Plans Combined [Member]
Benefit Payments Expected to be Paid [Abstract]
2020	1,827
2021	1,891
2022	1,964
2023	2,138
2024	2,208
2025 - 2029	$ 11,830

Employee Benefit Plans, Project

Employee Benefit Plans, Projected Benefit Obligation, Accumulated Benefit Obligation and Fair Value of Plan Assets (Details) - Defined Benefit Pension Plans Combined [Member] - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Projected Benefit Obligation and Fair Value of Plan Assets [Abstract]
Projected benefit obligation	$ 47,530	$ 41,511	$ 44,636
Fair value of plan assets	49,349	40,624	41,439
Accumulated Benefit Obligation and Fair Value of Plan Assets [Abstract]
Accumulated benefit obligation	44,587	39,100
Fair value of plan assets	$ 49,349	$ 40,624	$ 41,439

Employee Benefit Plans, Weighte

Employee Benefit Plans, Weighted-Average Assumptions Used (Details) - Defined Benefit Pension Plans Combined [Member] - Stock	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Weighted-Average Assumptions Used to Determine Benefit Obligations [Abstract]
Discount rate	3.10%	4.10%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost [Abstract]
Discount rate	4.10%	3.50%
Expected long-term return on plan assets	6.50%	6.75%
Target Asset Allocations [Abstract]
Percentage by which the return on plan assets should exceed the annual rate of inflation	3.00%
Maximum equity securities holdings in any one company	5.00%
Minimum number of individual stocks that must be included in the domestic stock portfolio	20
Minimum number of individual stocks that must be included in the international stock portfolio	30
Maximum fixed income securities holdings in any single issuer	5.00%
Minimum [Member]
Weighted-Average Assumptions Used to Determine Benefit Obligations [Abstract]
Rate of compensation increase	2.50%	2.50%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost [Abstract]
Rate of compensation increase	2.50%	2.50%
Target Asset Allocations [Abstract]
Investment performance objectives benchmark period	3 years
Maximum equity securities holdings in any one industry	20.00%
Maximum [Member]
Weighted-Average Assumptions Used to Determine Benefit Obligations [Abstract]
Rate of compensation increase	3.00%	3.00%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost [Abstract]
Rate of compensation increase	3.00%	3.00%
Target Asset Allocations [Abstract]
Investment performance objectives benchmark period	5 years
Maximum equity securities holdings in any one industry	25.00%
Equity Securities [Member] \| Minimum [Member]
Target Asset Allocations [Abstract]
Asset allocation of plan assets	50.00%
Weighted-average target asset allocations	50.00%
Equity Securities [Member] \| Maximum [Member]
Target Asset Allocations [Abstract]
Asset allocation of plan assets	70.00%
Weighted-average target asset allocations	70.00%
Large Cap [Member] \| Minimum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	60.00%
Large Cap [Member] \| Maximum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	95.00%
Mid Cap [Member] \| Minimum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	0.00%
Mid Cap [Member] \| Maximum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	25.00%
Small Cap [Member] \| Minimum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	0.00%
Small Cap [Member] \| Maximum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	10.00%
International Developed Nations [Member] \| Minimum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	0.00%
International Developed Nations [Member] \| Maximum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	25.00%
International Emerging Nations [Member] \| Minimum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	0.00%
International Emerging Nations [Member] \| Maximum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	10.00%
Fixed Income Securities [Member] \| Minimum [Member]
Target Asset Allocations [Abstract]
Asset allocation of plan assets	30.00%
Weighted-average target asset allocations	30.00%
Fixed Income Securities [Member] \| Maximum [Member]
Target Asset Allocations [Abstract]
Asset allocation of plan assets	50.00%
Weighted-average target asset allocations	50.00%
U.S. Treasuries [Member] \| Minimum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	15.00%
U.S. Treasuries [Member] \| Maximum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	55.00%
Federal Agency Securities [Member] \| Minimum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	0.00%
Federal Agency Securities [Member] \| Maximum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	22.00%
Corporate Bonds [Member] \| Minimum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	0.00%
Corporate Bonds [Member] \| Maximum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	40.00%
Mortgage-Backed Securities [Member] \| Minimum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	15.00%
Mortgage-Backed Securities [Member] \| Maximum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	55.00%
International [Member] \| Minimum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	0.00%
International [Member] \| Maximum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	20.00%
High Yield Bonds [Member] \| Minimum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	0.00%
High Yield Bonds [Member] \| Maximum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	20.00%
Cash and Cash Equivalents [Member] \| Minimum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	0.00%
Cash and Cash Equivalents [Member] \| Maximum [Member]
Target Asset Allocations [Abstract]
Weighted-average target asset allocations	10.00%

Employee Benefit Plans, Fair Va

Employee Benefit Plans, Fair Values of Pension Plan Assets (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value of Pension Plan Assets [Abstract]
Period to keep distributions in immediately available funds		1 year
Defined Benefit Pension Plans Combined [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets		$ 49,349	$ 40,624	$ 41,439
Defined Benefit Pension Plans Combined [Member] \| Cash and Money Market Funds [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[1]	682	1,498
Defined Benefit Pension Plans Combined [Member] \| Common Equity Securities [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[2]	662	512
Defined Benefit Pension Plans Combined [Member] \| Equity Mutual Funds [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[3]	29,677	23,637
Defined Benefit Pension Plans Combined [Member] \| U.S. Treasury Obligations [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets		615	591
Defined Benefit Pension Plans Combined [Member] \| Corporate and Foreign Bonds [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[4]	6,078	5,315
Defined Benefit Pension Plans Combined [Member] \| Fixed Income Mutual Funds [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[5]	11,635	9,071
Defined Benefit Pension Plans Combined [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets		42,656	34,718
Defined Benefit Pension Plans Combined [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Cash and Money Market Funds [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[1]	682	1,498
Defined Benefit Pension Plans Combined [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Common Equity Securities [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[2]	662	512
Defined Benefit Pension Plans Combined [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Equity Mutual Funds [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[3]	29,677	23,637
Defined Benefit Pension Plans Combined [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| U.S. Treasury Obligations [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets		0	0
Defined Benefit Pension Plans Combined [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Corporate and Foreign Bonds [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[4]	0	0
Defined Benefit Pension Plans Combined [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Fixed Income Mutual Funds [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[5]	11,635	9,071
Defined Benefit Pension Plans Combined [Member] \| Fair Value Measurements at Reporting Date Using Significant Other Observable Inputs (Level 2) [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets		6,693	5,906
Defined Benefit Pension Plans Combined [Member] \| Fair Value Measurements at Reporting Date Using Significant Other Observable Inputs (Level 2) [Member] \| Cash and Money Market Funds [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[1]	0	0
Defined Benefit Pension Plans Combined [Member] \| Fair Value Measurements at Reporting Date Using Significant Other Observable Inputs (Level 2) [Member] \| Common Equity Securities [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[2]	0	0
Defined Benefit Pension Plans Combined [Member] \| Fair Value Measurements at Reporting Date Using Significant Other Observable Inputs (Level 2) [Member] \| Equity Mutual Funds [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[3]	0	0
Defined Benefit Pension Plans Combined [Member] \| Fair Value Measurements at Reporting Date Using Significant Other Observable Inputs (Level 2) [Member] \| U.S. Treasury Obligations [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets		615	591
Defined Benefit Pension Plans Combined [Member] \| Fair Value Measurements at Reporting Date Using Significant Other Observable Inputs (Level 2) [Member] \| Corporate and Foreign Bonds [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[4]	6,078	5,315
Defined Benefit Pension Plans Combined [Member] \| Fair Value Measurements at Reporting Date Using Significant Other Observable Inputs (Level 2) [Member] \| Fixed Income Mutual Funds [Member]
Fair Value of Pension Plan Assets [Abstract]
Fair value of plan assets	[5]	$ 0	$ 0

[1]	The portfolios are designed to keep up to one year of distributions in immediately available funds.
[2]	This category includes investments in U.S. common stocks and foreign stocks trading in the U.S. widely distributed among consumer discretionary, consumer staples, healthcare, information technology, financial services, telecommunications, industrials, real estate, materials, and energy. The individual stocks are primarily large cap stocks which track with the S&P 500.
[3]	This category currently includes a majority of investments in closed-end mutual funds as well as domestic equity mutual funds and international mutual funds which give the portfolio exposure to mid and large cap index funds as well as international diversified index funds.
[4]	This category currently includes only U.S. corporate bonds and notes widely distributed among consumer discretionary, consumer staples, healthcare, information technology, energy, transportation, and financial services.
[5]	This category includes fixed income investments in mutual funds which include government, corporate and mortgage securities of both the U.S. and other countries. The mortgage-backed securities and non-U.S. corporate and sovereign investments add further diversity to the fixed income portion of the portfolio.

Employee Benefit Plans, Defined

Employee Benefit Plans, Defined Contribution Plan, Deferred Compensation and Other (Details)	12 Months Ended
	Dec. 31, 2019USD ($)Employee	Dec. 31, 2018USD ($)
Defined Contribution Plan [Abstract]
Maximum elective employee contribution percentage	15.00%
Company matching contribution percentage	100.00%
Maximum annual Company contribution for each employee	$ 2,800
Maximum annual Company contribution as a percentage of employee's compensation	4.00%
Annual Company discretionary contribution	$ 1,200
Number of employees participating in enhanced feature of plan \| Employee	49
Contributions to defined contribution plan	$ 300,000	$ 287,000
Deferred Compensation [Abstract]
Present value of future obligations	4,416,000	3,955,000
Total cash value of insurance policies	3,667,000	3,402,000
Net expenses under deferred compensation plans	670,000	32,000
Other [Abstract]
Amount payable upon retiree's death	2,000
Present value of future obligations	137,000	107,000
(Income) expenses under retiree life insurance program	$ 34,000	$ (10,000)

Stock Based Compensation (Detai

Stock Based Compensation (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)Officer$ / sharesshares	Dec. 31, 2018USD ($)Officer$ / sharesshares	May 02, 2016shares
Stock-Based Compensation [Abstract]
Number of retiring officers receiving accelerated vesting period \| Officer	1	1
LTIP [Member]
Stock-Based Compensation [Abstract]
Maximum number of shares of common stock that can be issued under the plan (in shares)			100,000
Term of plan	10 years
Maximum number of shares of common stock subject to awards that may be granted to a participant per calendar year (in shares)	2,000
LTIP [Member] \| Restricted Stock [Member]
Number of Shares [Roll Forward]
Nonvested at beginning of the period (in shares)	3,080	1,127
Granted (in shares)	6,963	3,743
Vested (in shares)	(2,701)	(1,790)
Forfeited (in shares)	0	0
Nonvested at end of the period (in shares)	7,342	3,080
Grant Date Weighted Average Fair Value [Abstract]
Nonvested at beginning of the period (in dollars per share) \| $ / shares	$ 33.85	$ 37.76
Granted (in dollars per share) \| $ / shares	33.61	32.70
Vested (in dollars per share) \| $ / shares	33.99	33.90
Forfeited (in dollars per share) \| $ / shares	0	0
Nonvested at end of the period (in dollars per share) \| $ / shares	$ 33.57	$ 33.85
Stock-Based Compensation Expense [Abstract]
Stock-based compensation expense \| $	$ 166	$ 80
Recognized tax benefits related to stock-based compensation expense \| $	48	23
Fair value of vested shares \| $	92	$ 61
Stock-based compensation expense not yet recognized \| $	$ 246
Period of recognition	3 years
LTIP [Member] \| Restricted Stock [Member] \| Officers and Key Employees [Member]
Stock-Based Compensation [Abstract]
Vesting period	3 years

Taxes Other than Income Taxes_2

Taxes Other than Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Components of Taxes Other than Income Taxes [Abstract]
Regulatory Assessment	$ 285	$ 261
Property	348	345
Payroll, net of amounts capitalized	564	538
Other	3	1
Total taxes other than income taxes	$ 1,200	$ 1,145

Income Taxes (Details)

Income Taxes (Details) $ in Thousands	12 Months Ended
Income Taxes (Details) $ in Thousands	Dec. 31, 2019USD ($)Position	Dec. 31, 2018USD ($)	Dec. 31, 2017
Provisions for Income Taxes [Abstract]
Federal current	$ 1,148	$ 1,715
State current	451	718
Federal deferred	475	216
State deferred	205	(119)
Federal investment tax credit, net of current utilization	(39)	(39)
Total income taxes	2,240	2,491
Reconciliation of Statutory Federal Tax Provision to Total Provision [Abstract]
Statutory Federal tax provision	3,495	3,332
State income taxes, net of Federal benefit	574	471
IRS TPR deduction	(1,642)	(1,307)
Tax-exempt interest	(25)	(22)
Amortization of investment tax credit	(39)	(39)
Cash value of life insurance	6	(13)
Amortization of excess accumulated deferred income taxes on accelerated depreciation	(149)	0
Other, net	20	69
Total income taxes	2,240	2,491
Regulatory Liabilities [Abstract]
Regulatory liabilities	$ 25,399	$ 26,814
Federal corporate tax rate	21.00%	21.00%	34.00%
Deferred Tax Assets [Abstract]
Reserve for doubtful accounts	$ 88	$ 88
Compensated absences	148	147
Deferred compensation	1,276	1,143
Excess accumulated deferred income taxes on accelerated depreciation	4,047	4,098
Deferred taxes associated with the gross-up of revenues necessary to return, in rates, the effect of temporary differences	2,104	2,077
Customers' advances for construction and contributions in aid of construction	998	577
Revenue reduction for tax rate change	7	333
Pensions	0	256
Other costs deducted for book, not for tax	69	40
Total deferred tax assets	8,737	8,759
Deferred Tax Liabilities [Abstract]
Accelerated depreciation	28,891	28,479
Basis differences from IRS TPR	11,311	9,367
Investment tax credit	384	411
Deferred taxes associated with the gross-up of revenues necessary to recover, in rates, the effect of temporary differences	6,987	6,124
Pension	525	0
Tax effect of pension regulatory asset	106	887
Unamortized debt issuance costs	531	197
Other costs deducted for tax, not for book	428	256
Total deferred tax liabilities	49,163	45,721
Net deferred tax liability	40,426	36,962
Valuation allowance	0	0
Uncertain tax positions	$ 0
Open tax year	2016 2017 2018
Number of new tax positions taken \| Position	0
Interest or penalties	$ 0	1
IRS TPR Catch-Up Deduction [Member]
Regulatory Liabilities [Abstract]
Regulatory liabilities	$ 3,671	3,887
Approved amortization period	15 years
Amortization of catch-up deduction	$ (216)
IRS TPR Ongoing Deductions Member [Member]
Regulatory Liabilities [Abstract]
Ongoing TPR deduction	$ (1,426)	$ (1,307)

Schedule II Valuation and Qua_2

Schedule II Valuation and Qualifying Accounts (Details) - Reserve for Uncollectible Accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Movement in Reserve [Roll Forward]
Balance at beginning of year	$ 305,000	$ 305,000
Additions - charged to cost and expenses	258,542	250,884
Additions - recoveries	51,900	57,633
Deductions	310,442	308,517
Balance at end of year	$ 305,000	$ 305,000