Summit Midstream Partners (SMLP) 8-K10 Aug 20Other EventsFinancial data

Company Profile

Cover Page

Cover Page	Aug. 07, 2020
Document Information [Line Items]
Amendment Flag	false
Entity Central Index Key	0001549922
Document Type	8-K
Document Period End Date	Aug. 7, 2020
Entity Registrant Name	Summit Midstream Partners, LP
Entity Incorporation, State or Country Code	DE
Entity File Number	001-35666
Entity Tax Identification Number	45-5200503
Entity Address, Address Line One	910 Louisiana Street
Entity Address, Address Line Two	Suite 4200
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77002
City Area Code	832
Local Phone Number	413-4770
Written Communications	false
Soliciting Material	false
Pre-commencement Tender Offer	false
Pre-commencement Issuer Tender Offer	false
Title of 12(b) Security	Common Units
Trading Symbol	SMLP
Security Exchange Name	NYSE
Entity Emerging Growth Company	false

UNAUDITED CONDENSED CONSOLIDATE

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 73,324	$ 9,530	$ 16,173
Restricted cash	4,057	27,392	0
Accounts receivable	78,948	97,418	97,936
Other current assets	4,471	5,521	4,388
Total current assets	160,800	139,861	118,497
Property, plant and equipment, net	1,870,083	1,882,489	1,964,099
Intangible assets, net	224,076	232,278	273,416
Goodwill		0	16,211
Investment in equity method investees	363,578	309,728	649,250
Other noncurrent assets	7,760	9,742	11,746
Total assets	2,626,297	2,574,098	3,033,219
Current liabilities:
Trade accounts payable	22,307	24,415	38,415
Accrued expenses	11,201	11,339	26,763
Deferred revenue	14,318	13,493	11,467
Ad valorem taxes payable	3,696	8,477	10,550
Accrued interest	15,405	12,346	12,339
Accrued environmental remediation	2,016	1,725	2,487
Other current liabilities	8,686	12,206	13,236
Current portion of long-term debt	7,800	5,546	14,500
Total current liabilities	85,429	89,547	129,757
Long-term debt	1,641,065	1,622,279	1,464,280
Noncurrent deferred revenue	43,045	38,709	39,504
Noncurrent accrued environmental remediation	2,618	2,926	3,149
Other noncurrent liabilities	8,044	7,951	4,962
Total liabilities	1,780,201	1,761,412	1,641,652
Commitments and contingencies
Partners' Capital
Series A Preferred Units	300,741	293,616	293,616
Common limited partner capital	300,801	305,550	543,479
Noncontrolling interest	182,213	186,070	554,472
Total partners' capital	783,755	785,236	1,391,567
Total liabilities, mezzanine capital and partners' capital	2,626,297	2,574,098	3,033,219
Mezzanine Capital
Mezzanine Capital
Subsidiary Series A Preferred Units	$ 62,341	$ 27,450	$ 0

UNAUDITED CONDENSED CONSOLIDA_2

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Subsidiary Series A preferred unitholders, issued	300,000	300,000	300,000
Subsidiary Series A preferred unitholders, outstanding	300,000	300,000	300,000
Mezzanine Capital
Subsidiary Series A preferred unitholders, issued	66,002	30,058
Subsidiary Series A preferred unitholders, outstanding	66,002	30,058

UNAUDITED CONDENSED CONSOLIDA_3

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Total revenues	$ 104,903	$ 131,408	$ 443,528	$ 506,653	$ 488,741
Costs and expenses:
Cost of natural gas and NGLs	$ 8,225	$ 31,759	$ 63,438	$ 107,661	$ 57,237
Type of Cost, Good or Service [Extensible List]	us-gaap:OilAndGasPurchasedMember	us-gaap:OilAndGasPurchasedMember	us-gaap:OilAndGasPurchasedMember	us-gaap:OilAndGasPurchasedMember	us-gaap:OilAndGasPurchasedMember
Operation and maintenance	$ 21,811	$ 24,222	$ 98,719	$ 100,978	$ 93,882
General and administrative	16,561	18,385	55,947	54,991	56,351
Depreciation and amortization	29,666	27,764	110,354	107,263	115,737
Transaction costs	11	2,337	3,017	0	50
Loss (gain) on asset sales, net	115	(961)	(1,536)	0	527
Long-lived asset impairment	3,821	44,951	60,507	7,186	188,702
Goodwill impairment			16,211	0	0
Total costs and expenses	80,210	148,457	406,657	378,079	512,486
Other (expense) income	(427)	209	451	(169)	298
Interest expense	(23,828)	(22,742)	(91,966)	(82,830)	(88,701)
Early extinguishment of debt			0	0	(22,039)
Income (loss) before income taxes and income (loss) from equity method investees	438	(39,582)	(54,644)	45,575	(134,187)
Income tax benefit (expense)	13	(257)	(1,231)	(367)	(504)
Income (loss) from equity method investees	3,311	(441)	(337,851)	(10,888)	(2,223)
Net income (loss)	3,762	(40,280)	(393,726)	34,320	(136,914)
Net (loss) income attributable to noncontrolling interest	(1,881)	(25,570)	(209,275)	2,774	46,497
Net income (loss) attributable to limited partners	5,643	(14,710)	(184,451)	31,546	(183,411)
Series A Preferred Units
Costs and expenses:
Net income (loss) attributable to limited partners	7,125	7,125	28,500	28,500	3,563
Series A Preferred Units \| Subsidiary
Costs and expenses:
Net income (loss) attributable to limited partners	945	0	58	0	0
Common units
Costs and expenses:
Net income (loss) attributable to limited partners	$ (2,427)	$ (21,835)	$ (213,009)	$ 3,046	$ (186,974)
Loss per limited partner unit:
Basic (in dollars per share)	$ (0.05)	$ (0.48)	$ (4.70)	$ 0.07	$ (4.13)
Diluted (in dollars per share)	$ (0.05)	$ (0.48)	$ (4.70)	$ 0.07	$ (4.13)
Weighted-average limited partner units outstanding:
Basic (shares)	45,319,000	45,319	45,319,000	45,319,000	45,319,000
Diluted (shares)	45,319,000	45,319	45,319,000	45,630,000	45,319,000
Gathering Services and Related Fees
Revenues:
Total revenues	$ 83,792	$ 86,964	$ 326,747	$ 344,616	$ 394,427
Natural Gas, NGLs and Condensate Sales
Revenues:
Total revenues	13,780	37,928	86,994	134,834	68,459
Other Revenues
Revenues:
Total revenues	$ 7,331	$ 6,516	$ 29,787	$ 27,203	$ 25,855

UNAUDITED CONDENSED CONSOLIDA_4

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF PARTNERS' CAPITAL - USD ($) $ in Thousands	Total	At Market Program	Noncontrolling Interest - Series A Preferred Units	Noncontrolling Interest - Series A Preferred UnitsAt Market Program	Noncontrolling Interest - Common Noncontrolling Interests	[1]	Noncontrolling Interest - Common Noncontrolling InterestsAt Market Program	[1]	Partners' Capital	Partners' CapitalAt Market Program	Previously adjusted	Previously adjustedNoncontrolling Interest - Series A Preferred Units	Previously adjustedNoncontrolling Interest - Common Noncontrolling Interests	[1]	Previously adjustedPartners' Capital	January 1, 2018 impact of Topic 606 day 1 adoption	January 1, 2018 impact of Topic 606 day 1 adoptionNoncontrolling Interest - Series A Preferred Units	January 1, 2018 impact of Topic 606 day 1 adoptionNoncontrolling Interest - Common Noncontrolling Interests	[1]	January 1, 2018 impact of Topic 606 day 1 adoptionPartners' Capital
Beginning balance at Dec. 31, 2016	$ 1,635,420		$ 0		$ 629,488				$ 1,005,932
Net income (loss)	(136,914)		3,563		46,497				(186,974)
Unit-based compensation	7,878		0		7,878				0
Effect of common unit issuances under SMLP LTIP	0		0		1,209				(1,209)
Tax withholdings and associated payments on vested SMLP LTIP awards	(2,236)		0		(2,236)				0
Net cash distributions to SMLP unitholders	(109,973)		(2,375)		(107,598)				0
Net cash distributions to Energy Capital Partners	(301,672)		0		0				(301,672)
Issuance of Series A Preferred Units, net of offering costs	293,238	$ 17,078	293,238	$ 0	0		$ 14,551		0	$ 2,527
Secondary offering of SMLP common units	94,640		0		60,981				33,659
Other	(199)		0		(199)				0
Ending balance at Dec. 31, 2017	1,501,474		294,426		653,240				553,808		$ 1,497,260	$ 294,426	$ 650,571		$ 552,263	$ 4,214	$ 0	$ 2,669		$ 1,545
Net income (loss)	34,320		28,500		2,774				3,046
Unit-based compensation	8,088		0		8,088				0
Effect of common unit issuances under SMLP LTIP	0		0		1,575				(1,575)
Tax withholdings and associated payments on vested SMLP LTIP awards	(1,974)		0		(1,974)				0
Net cash distributions to SMLP unitholders	(137,601)		(28,500)		(109,101)				0
Net cash distributions to Energy Capital Partners	(11,800)		0		0				(11,800)
Other	(940)		(810)		(130)				0
Ending balance at Dec. 31, 2018	1,391,567		293,616		554,472				543,479
Net income (loss)	(40,280)		7,125		(25,570)				(21,835)
Unit-based compensation	2,526		0		2,526				0
Effect of common unit issuances under SMLP LTIP	0		0		2,387				(2,387)
Tax withholdings and associated payments on vested SMLP LTIP awards	(2,524)		0		(2,524)				0
Net cash distributions to SMLP unitholders	(27,374)		0		(27,374)				0
Conversion of noncontrolling interest related to cancelation of subsidiary incentive distribution rights	0		0		(48,203)				48,203
Ending balance at Mar. 31, 2019	1,323,915		300,741		455,714				567,460
Beginning balance at Dec. 31, 2018	1,391,567		293,616		554,472				543,479
Net income (loss)	(393,784)		28,500		(209,275)				(213,009)
Unit-based compensation	8,171		0		8,171				0
Effect of common unit issuances under SMLP LTIP	0		0		2,664				(2,664)
Tax withholdings and associated payments on vested SMLP LTIP awards	(2,614)		0		(2,614)				0
Net cash distributions to SMLP unitholders	(97,374)		(28,500)		(68,874)				0
Net cash distributions to Energy Capital Partners	(120,730)		0		0				(120,730)
Conversion of noncontrolling interest related to cancelation of subsidiary incentive distribution rights	0		0		(48,203)				48,203
Conversion of noncontrolling interest related to partial cancellation of subsidiary of DPPO	0		0		(50,271)				50,271
Ending balance at Dec. 31, 2019	785,236		293,616		186,070				305,550
Net income (loss)	2,817		7,125		(1,881)				(2,427)
Unit-based compensation	2,723		0		2,723				0
Effect of common unit issuances under SMLP LTIP	0		0		2,322				(2,322)
Tax withholdings and associated payments on vested SMLP LTIP awards	(984)		0		(984)				0
Net cash distributions to SMLP unitholders	(6,037)		0		(6,037)				0
Ending balance at Mar. 31, 2020	$ 783,755		$ 300,741		$ 182,213				$ 300,801

[1]	Prior to the GP Buy-In Transaction, common noncontrolling interests reported by Summit Investments included equity interests in SMLP that were not owned by Summit Investments.

UNAUDITED CONDENSED CONSOLIDA_5

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income (loss)	$ 3,762	$ (40,280)	$ (393,726)	$ 34,320	$ (136,914)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	29,900	28,153	111,574	106,930	115,134
Noncash lease expense	473	765	3,086	0	0
Amortization of debt issuance costs	1,582	1,549	6,313	6,142	5,445
Unit-based and noncash compensation	2,723	2,526	8,171	8,328	7,951
(Income) loss from equity method investees	(3,311)	441	337,851	10,888	2,223
Distributions from equity method investees	7,494	8,583	37,300	35,271	40,220
Loss (gain) on asset sales, net	115	(961)	(1,536)	0	527
Long-lived asset impairment	3,821	44,951	60,507	7,186	188,702
Goodwill impairment			16,211	0	0
Early extinguishment of debt			0	0	22,039
Write-off of debt issuance costs			0	0	302
Changes in operating assets and liabilities:
Accounts receivable	18,470	4,675	(5,466)	(25,635)	25,063
Trade accounts payable	3,973	274	(96)	85	(3,256)
Accrued expenses	(138)	(1,274)	(10,572)	13,903	1,227
Deferred revenue, net	5,161	2,323	1,683	5,355	(40,758)
Ad valorem taxes payable	(4,781)	(6,184)	(1,525)	2,211	(2,248)
Accrued interest	3,059	3,153	7	(140)	(7,736)
Accrued environmental remediation, net	(17)	(548)	(1,152)	292	(4,109)
Other, net	(2,085)	(2,953)	(6,889)	1,094	(764)
Net cash provided by operating activities	70,201	45,193	161,741	206,230	213,048
Cash flows from investing activities:
Capital expenditures	(18,583)	(60,848)	(182,291)	(200,586)	(124,215)
Proceeds from asset sale	0	89,461	102,111	496	2,300
Contributions to equity method investees			0	(4,924)	(25,513)
Distributions from equity method investment			7,313	0	0
Investment in equity method investee	(58,033)	0	(18,316)	0	0
Other, net	217	(120)	313	(284)	(458)
Net cash (used in) provided by investing activities	(76,399)	28,493	(90,870)	(205,298)	(147,886)
Cash flows from financing activities:
Net cash Distributions to noncontrolling interest SMLP unitholders	(6,037)	(27,374)	(68,874)	(109,101)	(107,598)
Distributions to mandatorily redeemable Class C unitholders			0	0	(99,323)
Distributions to Energy Capital Partners			(120,730)	(11,800)	(301,672)
Borrowings under Revolving Credit Facility	55,000	69,000	369,000	289,000	247,500
Borrowings under SMP Holdings Term Loan B			0	0	300,000
Repayments under SMP Holdings term loan	(750)	(12,250)	(65,250)	(49,250)	(24,000)
Repayments under Revolving Credit Facility	(34,000)	(101,000)	(158,000)	(84,000)	(634,500)
Debt issuance costs	(101)	(179)	(673)	(518)	(25,061)
Payment of redemption and call premiums on senior notes			0	0	(17,932)
Proceeds from ATM Program common unit issuances, net of costs			0	0	17,078
Proceeds from secondary offering common units, net of costs			0	0	94,640
Proceeds from issuance of Series A preferred units, net of costs	33,946	0	27,392	0	293,238
Issuance of senior notes			0	0	500,000
Tender and redemption of senior notes			0	0	(300,000)
Other, net	(1,401)	(2,968)	(4,487)	(4,186)	(3,124)
Net cash provided by (used in) financing activities	46,657	(74,771)	(50,122)	1,645	(63,129)
Net change in cash, cash equivalents and restricted cash	40,459	(1,085)	20,749	2,577	2,033
Cash, cash equivalents and restricted cash, beginning of period	36,922	16,173	16,173	13,596	11,563
Cash, cash equivalents and restricted cash, end of period	77,381	15,088	36,922	16,173	13,596
Supplemental cash flow disclosures:
Cash interest paid	19,660	19,932	92,536	85,233	88,193
Less capitalized interest	491	1,915	6,974	8,497	2,579
Interest paid (net of capitalized interest)	19,169	18,017	85,562	76,736	85,614
Cash paid for taxes	0	0	150	175	0
Noncash investing and financing activities
Capital expenditures in trade accounts payable (period-end accruals)	13,765	23,389	19,846	33,750	11,792
Contribution of Property			23,643	0	0
Capital expenditures relating to contributions in aid of construction for Topic 606 day 1 adoption			0	33,123	0
Right-of-use assets relating to ASC Topic 842			5,448	0	0
ASC Topic 842
Noncash investing and financing activities
Right-of-use assets relating to ASC Topic 842	$ 0	$ 5,448
Series A Preferred Units
Cash flows from financing activities:
Distributions to unitholders			$ (28,500)	$ (28,500)	$ (2,375)

UNAUDITED CONDENSED CONSOLIDA_6

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Statement Of Cash Flows [Abstract]
Net of cash	$ 1,475	$ 1,475
Cash and cash equivalents	73,324	9,530
Restricted cash	4,057	27,392
Total cash, cash equivalents and restricted cash	$ 77,381	$ 36,922

ORGANIZATION, BUSINESS OPERATIO

ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION	1. ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION Organization. As described further in Note 17, the Partnership closed on its Purchase Agreement (the “Purchase Agreement”) with affiliates of Energy Capital Partners II, LLC, a Delaware limited liability company (“ECP”) on May 28, 2020 to acquire all the outstanding limited liability company interests of Summit Midstream Partners, LLC a Delaware limited liability company (“Summit Investments”). We refer to the transactions contemplated by the Purchase Agreement as the (“GP Buy-In Buy-In Under GAAP, the GP Buy-In Buy-In Buy-In Business Operations. fee-based • Summit Utica, a natural gas gathering system operating in the Appalachian Basin, which includes the Utica and Point Pleasant shale formations in southeastern Ohio; • Ohio Gathering, a natural gas gathering system and a condensate stabilization facility operating in the Appalachian Basin, which includes the Utica and Point Pleasant shale formations in southeastern Ohio; • Polar and Divide, a crude oil and produced water gathering system and transmission pipeline operating in the Williston Basin, which includes the Bakken and Three Forks shale formations in northwestern North Dakota; • Bison Midstream, an associated natural gas gathering system operating in the Williston Basin, which includes the Bakken and Three Forks shale formations in northwestern North Dakota; • Niobrara G&P, an associated natural gas gathering and processing system operating in the DJ Basin, which includes the Niobrara and Codell shale formations in northeastern Colorado and southeastern Wyoming; • Summit Permian, an associated natural gas gathering and processing system operating in the northern Delaware Basin, which includes the Wolfcamp and Bone Spring formations, in southeastern New Mexico; • Double E, a 1.35 Bcf/d natural gas transmission pipeline that is under development and will provide transportation service from multiple receipt points in the Delaware Basin to various delivery points in and around the Waha Hub in Texas; • Grand River, a natural gas gathering and processing system operating in the Piceance Basin, which includes the Mesaverde formation and the Mancos and Niobrara shale formations in western Colorado;	1. ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION Organization. As described further in Note 19, the Partnership closed on its Purchase Agreement (the “Purchase Agreement”) with affiliates of Energy Capital Partners II, LLC, a Delaware limited liability company (“ECP”) on May 28, 2020 to acquire all the outstanding limited liability company interests of Summit Midstream Partners, LLC a Delaware limited liability company (“Summit Investments”). We refer to the transactions contemplated by the Purchase Agreement as the (“GP Buy-In Buy-In Under GAAP, the GP Buy-In Buy-In Buy-In Business Operations. fee-based • Summit Utica, a natural gas gathering system operating in the Appalachian Basin, which includes the Utica and Point Pleasant shale formations in southeastern Ohio; • Ohio Gathering, a natural gas gathering system and a condensate stabilization facility operating in the Appalachian Basin, which includes the Utica and Point Pleasant shale formations in southeastern Ohio; • Polar and Divide, a crude oil and produced water gathering system and transmission pipeline operating in the Williston Basin, which includes the Bakken and Three Forks shale formations in northwestern North Dakota; • Bison Midstream, an associated natural gas gathering system operating in the Williston Basin, which includes the Bakken and Three Forks shale formations in northwestern North Dakota; • Niobrara G&P, an associated natural gas gathering and processing system operating in the DJ Basin, which includes the Niobrara and Codell shale formations in northeastern Colorado and southeastern Wyoming; • Summit Permian, an associated natural gas gathering and processing system operating in the northern Delaware Basin, which includes the Wolfcamp and Bone Spring formations, in southeastern New Mexico; • Double E, a 1.35 Bcf/d natural gas transmission pipeline that is under development and will provide transportation service from multiple receipt points in the Delaware Basin to various delivery points in and around the Waha Hub in Texas; • Grand River, a natural gas gathering and processing system operating in the Piceance Basin, which includes the Mesaverde formation and the Mancos and Niobrara shale formations in western Colorado; • DFW Midstream, a natural gas gathering system operating in the Fort Worth Basin, which includes the Barnett Shale formation in north-central Texas; and • Mountaineer Midstream, a natural gas gathering system operating in the Appalachian Basin, which includes the Marcellus Shale formation in northern West Virginia. Until March 22, 2019, we owned Tioga Midstream, a crude oil, produced water and associated natural gas gathering system operating in the Williston Basin. Refer to Note 17 for details on the sale of Tioga Midstream. In June 2019, in conjunction with the Double E Project, Summit Permian Transmission entered into a definitive joint venture agreement (the “Agreement”) with an affiliate of Double E’s foundation shipper (the “JV Partner”) to fund the capital expenditures associated with the Double E Project. Refer to Note 8 for additional details. Other than our investments in Double E and Ohio Gathering, all of our business activities are conducted through wholly owned operating subsidiaries. Presentation and Consolidation. The consolidated financial statements include the assets, liabilities and results of operations of SMLP and its subsidiaries. All intercompany transactions among the consolidated entities have been eliminated in consolidation. Comprehensive income or loss is the same as net income or loss for all periods presented. • DFW Midstream, a natural gas gathering system operating in the Fort Worth Basin, which includes the Barnett Shale formation in north-central Texas; and • Mountaineer Midstream, a natural gas gathering system operating in the Appalachian Basin, which includes the Marcellus Shale formation in northern West Virginia. Other than our investments in Double E and Ohio Gathering, all of our business activities are conducted through wholly owned operating subsidiaries. Presentation and Consolidation. These unaudited condensed consolidated financial statements have been prepared pursuant to the rules and the regulations of the SEC. Certain information and note disclosures normally included in the annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules and regulations. We believe that the disclosures made are adequate to make the information not misleading. In the opinion of management, the unaudited condensed consolidated financial statements contain all adjustments which are necessary to fairly present the unaudited condensed consolidated balance sheet as of March 31, 2020, the unaudited condensed consolidated statements of operations and statements of partners’ capital for the three months ended March 31, 2020 and 2019 and the unaudited condensed consolidated statements of cash flows for the three months ended March 31, 2020 and 2019. The balance sheet at December 31, 2019 included herein was derived from our audited financial statements, but does not include all disclosures required by GAAP. These unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto that are included in our annual report on Form 10-K 8-K. Risks and Uncertainties. COVID-19 COVID-19 COVID-19 COVID-19 The full extent to which our operations may be impacted by the COVID-19

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	Mar. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Except for the changes below, there have been no changes to our significant accounting policies since December 31, 2019. Recent Accounting Pronouncements. Recently Adopted Accounting Pronouncements • ASU No. 2018-13 2018-13”). 2018-13 2018-13 2018-13 2018-13 • ASU No. 2016-13 2016-13”). 2016-13 off-balance 2016-13 Accounting Pronouncements Pending Adoption • ASU No. 2020-04 2020-04”). 2020-04 2020-04 2020-04	2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Cash, Cash Equivalents and Restricted Cash. Accounts Receivable. Property, Plant and Equipment. We record depreciation on a straight-line basis over an asset’s estimated useful life. We base our estimates for useful life on various factors including age (in the case of acquired assets), manufacturing specifications, technological advances and historical data concerning useful lives of similar assets. Estimates of useful lives follow. Useful lives (In years) Gathering and processing systems and related equipment 12-30 Other 4-15 Construction in progress is depreciated consistent with its applicable asset class once it is placed in service. Land and line fill are not depreciated. We base an asset’s carrying value on estimates, assumptions and judgments for useful life and salvage value. Upon sale, retirement or other disposal, we remove the carrying value of an asset and its accumulated depreciation from our balance sheet and recognize the related gain or loss, if any. Accrued capital expenditures are reflected in trade accounts payable. Asset Retirement Obligations. Amortizing Intangibles. We amortize all other gas gathering contracts, or contract intangibles, over the period of economic benefit based upon expected revenues over the life of the contract. The useful life of these contracts ranges from 3 years to 25 years. We recognize the amortization expense associated with these contracts in Depreciation and amortization expense. We have rights-of-way rights-of-way. rights-of-way rights-of-way rights-of-way Goodwill. Equity Method Investments. one-month We recognize an other-than-temporary impairment for losses in the value of equity method investees when evidence indicates that the carrying amount is no longer supportable. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the equity method investee to sustain an earnings capacity that would justify the carrying amount of the investment. A current fair value of an investment that is less than its carrying amount may indicate a loss in value of the investment. We evaluate our equity method investments whenever a triggering event exists that would indicate a need to assess the investment for potential impairment. Other Noncurrent Assets. Debt Issuance Costs. Impairment of Long-Lived Assets. Derivative Contracts. Accounting standards related to derivative instruments and hedging activities allow for normal purchase or sale elections and hedge accounting designations, which generally eliminate or defer the requirement for mark-to-market Restructuring Costs. Fair Value of Financial Instruments. • Level 1. Inputs represent quoted prices in active markets for identical assets or liabilities; • Level 2. Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly (for example, quoted market prices for similar assets or liabilities in active markets or quoted market prices for identical assets or liabilities in markets not considered to be active, inputs other than quoted prices that are observable for the asset or liability, or market-corroborated inputs); and • Level 3. Inputs that are not observable from objective sources, such as management’s internally developed assumptions used in pricing an asset or liability (for example, an internally developed present value of future cash flows model that underlies management’s fair value measurement). Commitments and Contingencies. Revenue Recognition. fee-based We recognize revenue earned from fee-based percent-of-proceeds We provide gathering and/or processing services principally under contracts that contain one or more of the following arrangements: • Fee-based fee-based • Percent-of-proceeds percent-of-proceeds Certain of our gathering and/or processing agreements provide for monthly or annual MVCs. Under these MVCs, our customers agree to ship and/or process a minimum volume of production on our gathering systems or to pay a minimum monetary amount over certain periods during the term of the MVC. A customer must make a shortfall payment to us at the end of the contracted measurement period if its actual throughput volumes are less than its contractual MVC for that period. Certain customers are entitled to utilize shortfall payments to offset gathering fees in one or more subsequent contracted measurement periods to the extent that such customer’s throughput volumes in a subsequent contracted measurement period exceed its MVC for that contracted measurement period. We recognize customer obligations under their MVCs as revenue and contract assets when (i) we consider it remote that the customer will utilize shortfall payments to offset gathering or processing fees in excess of its MVCs in subsequent periods; (ii) the customer incurs a shortfall in a contract with no banking mechanism or claw back provision; (iii) the customer’s banking mechanism has expired; or (iv) it is remote that the customer will use its unexercised right. In making this determination, we consider both quantitative and qualitative facts and circumstances, including, but not limited to, contract terms, capacity of the associated pipeline or receipt point and/or expectations regarding future investment, drilling and production. Unit-Based Compensation. Income Taxes. In general, legal entities that are chartered, organized or conducting business in the state of Texas are subject to a franchise tax (the “Texas Margin Tax”). The Texas Margin Tax has the characteristics of an income tax because it is determined by applying a tax rate to a tax base that considers both revenues and expenses. Our financial statements reflect provisions for these tax obligations. Earnings or Loss Per Unit. two-class Environmental Matters. Recent Accounting Pronouncements. Recently Adopted Accounting Pronouncements • ASU No. 2016-02 right-of-use Accounting Pronouncements Pending Adoption • ASU No. 2018-13 2018-13”). 2018-13 2018-13 2018-13 2018-13 • ASU No. 2016-13 2016-13”). 2016-13 off-balance 2016-13

REVENUE

REVENUE	3 Months Ended	12 Months Ended
REVENUE	Mar. 31, 2020	Dec. 31, 2019
Revenue From Contract With Customer [Abstract]
REVENUE	3. REVENUE The majority of our revenue is derived from long-term, fee-based fee-based percent-of-proceeds The transaction price in our contracts is primarily based on the volume of natural gas, crude oil or produced water transferred by our gathering systems to the customer’s agreed upon delivery point multiplied by the contractual rate. For contracts that include MVCs, variable consideration up to the MVC will be included in the transaction price. For contracts that do not include MVCs, we do not estimate variable consideration because the performance obligations are completed and settled on a daily basis. For contracts containing noncash consideration such as fuel received in-kind, We have contracts with MVCs that are variable and constrained. Contracts with greater than monthly MVCs are reviewed on a quarterly basis and adjustments to those estimates are made during each respective reporting period, if necessary. The transaction price is allocated if the contract contains more than one performance obligation such as contracts that include MVCs. The transaction price allocated is based on the MVC for the applicable measurement period. Performance obligations. Performance obligations for gathering services are generally satisfied over time. We utilize either an output method (i.e., measure of progress) for guaranteed, stand-ready service contracts or an asset/system delivery time estimate for non-guaranteed, as-available Performance obligations for the sale of natural gas, NGLs and condensate are satisfied at a point in time. There are no significant judgments for these transactions because the customer obtains control based on an agreed upon delivery point. Certain of our gathering and/or processing agreements provide for monthly or annual MVCs. Under these MVCs, our customers agree to ship and/or process a minimum volume of production on our gathering systems or to pay a minimum monetary amount over certain periods during the term of the MVC. A customer must make a shortfall payment to us at the end of the contracted measurement period if its actual throughput volumes are less than its contractual MVC for that period. Certain customers are entitled to utilize shortfall payments to offset gathering fees in one or more subsequent contracted measurement periods to the extent that such customer’s throughput volumes in a subsequent contracted measurement period exceed its MVC for that contracted measurement period. We recognize customer obligations under their MVCs as revenue and contract assets when (i) we consider it remote that the customer will utilize shortfall payments to offset gathering or processing fees in excess of its MVCs in subsequent periods; (ii) the customer incurs a shortfall in a contract with no banking mechanism or claw back provision; (iii) the customer’s banking mechanism has expired; or (iv) it is remote that the customer will use its unexercised right. Our services are typically billed on a monthly basis and we do not offer extended payment terms. We do not have contracts with financing components. The following table presents estimated revenue expected to be recognized during the remainder of 2020 and over the remaining contract period related to performance obligations that are unsatisfied and are comprised of estimated MVC shortfall payments. We applied the practical expedient in paragraph 606-10-50-14 2020 2021 2022 2023 2024 Thereafter (In thousands) Gathering services and related fees $ 86,916 $ 102,127 $ 84,736 $ 66,693 $ 50,608 $ 58,672 Revenue by Category. Reportable Segments Three months ended March 31, 2020 Utica Williston DJ Permian Piceance Barnett Marcellus Total All other Total (In thousands) Major products / services lines Gathering services and related fees $ 6,962 $ 23,797 $ 6,855 $ 2,311 $ 27,189 $ 10,443 $ 6,235 $ 83,792 $ — $ 83,792 Natural gas, NGLs and condensate sales — 4,324 70 4,512 1,003 3,871 — 13,780 — 13,780 Other revenues — 3,142 1,034 187 1,065 1,260 — 6,688 643 7,331 Total $ 6,962 $ 31,263 $ 7,959 $ 7,010 $ 29,257 $ 15,574 $ 6,235 $ 104,260 $ 643 $ 104,903 Reportable Segments Three months ended March 31, 2019 Utica Williston DJ Permian Piceance Barnett Marcellus Total All other Total (In thousands) Major products / services lines Gathering services and related fees $ 7,495 $ 25,706 $ 3,724 $ 366 $ 31,840 $ 13,025 $ 6,197 $ 88,353 $ (1,389 ) $ 86,964 Natural gas, NGLs and condensate sales — 5,585 85 4,221 2,302 604 — 12,797 25,131 37,928 Other revenues — 2,908 1,007 32 1,138 1,656 — 6,741 (225 ) 6,516 Total $ 7,495 $ 34,199 $ 4,816 $ 4,619 $ 35,280 $ 15,285 $ 6,197 $ 107,891 $ 23,517 $ 131,408 Contract balances. March 31, 2020 December 31, 2019 (In thousands) Contract assets, beginning of period $ 3,902 $ 8,755 Additions 13,877 18,077 Transfers out (425 ) (22,930 ) Contract assets, end of period $ 17,354 $ 3,902 As of March 31, 2020, receivables with customers totaled $58.0 million and contract assets totaled $17.4 million which were included in the Accounts receivable caption on the unaudited condensed consolidated balance sheet. As of December 31, 2019, receivables with customers totaled $90.4 million and contract assets totaled $3.9 million which were included in the Accounts receivable caption on the unaudited condensed consolidated balance sheet. Contract liabilities (deferred revenue) relate to the advance consideration received from customers primarily for contributions in aid of construction. We recognize contract liabilities under these arrangements in revenue over the contract period. For the three months ended March 31, 2020 and 2019, we recognized $2.4 million and $2.7 million of gathering services and related fees which were included in the contract liability balance as of the beginning of the period. See Note 8 for additional details.	3. REVENUE The majority of our revenue is derived from long-term, fee-based fee-based percent-of-proceeds The transaction price in our contracts is primarily based on the volume of natural gas, crude oil or produced water transferred by our gathering systems to the customer’s agreed upon delivery point multiplied by the contractual rate. For contracts that include MVCs, variable consideration up to the MVC will be included in the transaction price. For contracts that do not include MVCs, we do not estimate variable consideration because the performance obligations are completed and settled on a daily basis. For contracts containing noncash consideration such as fuel received in-kind, We have contracts with MVCs that are variable and constrained. Contracts with greater than monthly MVCs are reviewed on a quarterly basis and adjustments to those estimates are made during each respective reporting period, if necessary. The transaction price is allocated if the contract contains more than one performance obligation such as contracts that include MVCs. The transaction price allocated is based on the MVC for the applicable measurement period. Performance obligations services such as contracts containing MVCs. These performance obligations would also be satisfied when the related natural gas, crude oil and produced water are received and transferred to an agreed upon delivery point. In these instances, we allocate the contract’s transaction price to each performance obligation using our best estimate of the standalone selling price of each service in the contract. Performance obligations for gathering services are generally satisfied over time. We utilize either an output method (i.e., measure of progress) for guaranteed, stand-ready service contracts or an asset/system delivery time estimate for non-guaranteed, as-available Performance obligations for the sale of natural gas, NGLs and condensate are satisfied at a point in time. There are no significant judgments for these transactions because the customer obtains control based on an agreed upon delivery point. Certain of our gathering and/or processing agreements provide for monthly or annual MVCs. Under these MVCs, our customers agree to ship and/or process a minimum volume of production on our gathering systems or to pay a minimum monetary amount over certain periods during the term of the MVC. A customer must make a shortfall payment to us at the end of the contracted measurement period if its actual throughput volumes are less than its contractual MVC for that period. Certain customers are entitled to utilize shortfall payments to offset gathering fees in one or more subsequent contracted measurement periods to the extent that such customer’s throughput volumes in a subsequent contracted measurement period exceed its MVC for that contracted measurement period. We recognize customer obligations under their MVCs as revenue and contract assets when (i) we consider it remote that the customer will utilize shortfall payments to offset gathering or processing fees in excess of its MVCs in subsequent periods; (ii) the customer incurs a shortfall in a contract with no banking mechanism or claw back provision; (iii) the customer’s banking mechanism has expired; or (iv) it is remote that the customer will use its unexercised right. Our services are typically billed on a monthly basis and we do not offer extended payment terms. We do not have contracts with financing components. The following table presents estimated revenue expected to be recognized over the remaining contract period related to performance obligations that are unsatisfied and are comprised of estimated MVC shortfall payments. We applied the practical expedient in paragraph 606-10-50-14 2020 2021 2022 2023 2024 Thereafter (In thousands) Gathering services and related fees $ 122,055 $ 102,127 $ 84,736 $ 66,693 $ 50,608 $ 59,602 Revenue by Category Reportable Segments Year ended December 31, 2019 Utica Williston DJ Basin Permian Piceance Barnett Marcellus Total All other Total (In thousands) Major products / services lines Gathering services and related fees $ 31,926 $ 77,626 $ 21,940 $ 3,610 $ 121,357 $ 47,862 $ 24,471 $ 328,792 $ (2,045 ) $ 326,747 Natural gas, NGLs and condensate sales — 16,461 389 16,383 7,954 17,147 — 58,334 28,660 86,994 Other revenues 2,065 11,564 3,721 310 4,327 6,793 — 28,780 1,007 29,787 Total $ 33,991 $ 105,651 $ 26,050 $ 20,303 $ 133,638 $ 71,802 $ 24,471 $ 415,906 $ 27,622 $ 443,528 Reportable Segments Year ended December 31, 2018 Utica Williston DJ Basin Permian Piceance Barnett Marcellus Total All other Total (In thousands) Major products / services lines Gathering services and related fees $ 35,233 $ 79,606 $ 11,251 $ 115 $ 135,810 $ 59,030 $ 29,573 $ 350,618 $ (6,002 ) $ 344,616 Natural gas, NGLs and condensate sales — 31,840 371 843 14,800 2,523 — 50,377 84,457 134,834 Other revenues — 12,204 3,672 — 4,909 6,712 — 27,497 (294 ) 27,203 Total $ 35,233 $ 123,650 $ 15,294 $ 958 $ 155,519 $ 68,265 $ 29,573 $ 428,492 $ 78,161 $ 506,653 Contract balances December 31, 2019 December 31, 2018 (In thousands) Contract assets, beginning of period $ 8,755 $ — Additions 18,077 26,403 Transfers out (22,930 ) (17,648 ) Contract assets, end of period $ 3,902 $ 8,755 As of December 31, 2019, receivables with customers totaled $90.4 million and contract assets totaled $3.9 million which were included in the Accounts receivable caption on the consolidated balance sheet. As of December 31, 2018, receivables with customers totaled $82.9 million and contract assets totaled $8.8 million which were included in the Accounts receivable caption on the consolidated balance sheet. Contract liabilities (deferred revenue) relate to the advance consideration received from customers primarily for contributions in aid of construction. We recognize contract liabilities under these arrangements in revenue over the contract period. For the years ended December 31, 2019 and 2018, we recognized $10.1 million and $10.8 million, respectively, of gathering services and related fees which was included in the contract liability balance as of the beginning of the period. See Note 9 for additional details.

SEGMENT INFORMATION

SEGMENT INFORMATION	3 Months Ended	12 Months Ended
SEGMENT INFORMATION	Mar. 31, 2020	Dec. 31, 2019
Segment Reporting [Abstract]
SEGMENT INFORMATION	4. SEGMENT INFORMATION As of March 31, 2020, our reportable segments are: • the Utica Shale, which is served by Summit Utica; • Ohio Gathering, which includes our ownership interest in OGC and OCC; • the Williston Basin, which is served by Polar and Divide and Bison Midstream; • the DJ Basin, which is served by Niobrara G&P; • the Permian Basin, which is served by Summit Permian; • the Piceance Basin, which is served by Grand River; • the Barnett Shale, which is served by DFW Midstream; and • the Marcellus Shale, which is served by Mountaineer Midstream. Until March 22, 2019, we owned Tioga Midstream, a crude oil, produced water and associated natural gas gathering system operating in the Williston Basin. Until December 1, 2019, we owned certain assets in the Red Rock Gathering system operating in the Piceance Basin. Refer to Note 16 to the unaudited condensed consolidated financial statements for details on the sale of Tioga Midstream and on the sale of certain assets in the Red Rock Gathering system. Each of our reportable segments provides midstream services in a specific geographic area. Our reportable segments reflect the way in which we internally report the financial information used to make decisions and allocate resources in connection with our operations. The Ohio Gathering reportable segment includes our investment in Ohio Gathering. Income or loss from equity method investees, as reflected on the unaudited condensed consolidated statements of operations, relates to Ohio Gathering and is recognized and disclosed on a one-month For the three months ended March 31, 2020, other than the investment activity described in Note 7, Double E did not have any results of operations given that the Double E Project is currently under development. The Double E Project is expected to be operational in the third quarter of 2021. Corporate and Other represents those results that are: (i) not specifically attributable to a reportable segment; (ii) not individually reportable (such as Double E); or (iii) that have not been allocated to our reportable segments for the purpose of evaluating their performance, including certain general and administrative expense items, certain natural gas and crude oil marketing services, construction management fees related to the Double E Project and transaction costs. Assets by reportable segment follow. March 31, 2020 December 31, 2019 (In thousands) Assets (1): Utica Shale $ 205,341 $ 206,368 Ohio Gathering 271,268 275,000 Williston Basin 452,684 452,152 DJ Basin 200,473 205,308 Permian Basin 184,043 185,708 Piceance Basin 622,403 631,140 Barnett Shale 345,248 350,638 Marcellus Shale 184,279 184,631 Total reportable segment assets 2,465,739 2,490,945 Corporate and Other 160,558 83,153 Total assets $ 2,626,297 $ 2,574,098 (1) At March 31, 2020, Corporate and Other included $92.3 million relating to our investment in Double E (included in the Investment in equity method investees caption of the unaudited condensed consolidated balance sheet). At December 31, 2019, Corporate and Other included $34.7 million relating to our investment in Double E. Revenues by reportable segment follow. Three months ended March 31, 2020 2019 (In thousands) Revenues (1): Utica Shale $ 6,962 $ 7,495 Williston Basin 31,263 34,199 DJ Basin 7,959 4,816 Permian Basin 7,010 4,619 Piceance Basin 29,257 35,280 Barnett Shale 15,574 15,285 Marcellus Shale 6,235 6,197 Total reportable segments revenue 104,260 107,891 Corporate and Other 643 26,838 Eliminations — (3,321 ) Total revenues $ 104,903 $ 131,408 (1) Excludes revenues earned by Ohio Gathering due to equity method accounting. Counterparties accounting for more than 10% of total revenues were as follows: Three months ended March 31, 2020 2019 Percentage of total revenues (1): Counterparty A - Piceance Basin 11 % * (1) Excludes revenues earned by Ohio Gathering due to equity method accounting. * Less than 10% Depreciation and amortization, including the amortization expense associated with our favorable gas gathering contracts as reported in Other revenues, by reportable segment follows. Three months ended March 31, 2020 2019 (In thousands) Depreciation and amortization (1): Utica Shale $ 1,927 $ 1,908 Williston Basin 6,495 5,436 DJ Basin 1,527 799 Permian Basin 1,345 1,072 Piceance Basin 11,298 11,791 Barnett Shale (2) 4,032 4,330 Marcellus Shale 2,300 2,283 Total reportable segment depreciation and amortization 28,924 27,619 Corporate and Other 976 534 Total depreciation and amortization $ 29,900 $ 28,153 (1) Excludes depreciation and amortization recognized by Ohio Gathering due to equity method accounting. (2) Includes the amortization expense associated with our favorable gas gathering contracts as reported in Other revenues. Cash paid for capital expenditures by reportable segment follow. Three months ended March 31, 2020 2019 (In thousands) Cash paid for capital expenditures (1): Utica Shale $ 909 $ 101 Williston Basin 4,943 8,023 DJ Basin 6,298 28,356 Permian Basin 3,281 7,057 Piceance Basin 346 1,226 Barnett Shale (2) 657 (118 ) Marcellus Shale 422 102 Total reportable segment capital expenditures 16,856 44,747 Corporate and Other 1,727 16,101 Total cash paid for capital expenditures $ 18,583 $ 60,848 (1) Excludes cash paid for capital expenditures by Ohio Gathering due to equity method accounting. (2) For the three months ended March 31, 2019, the amount includes sales tax reimbursements of $1.1 million. During the three months ended March 31, 2019, Corporate and Other included cash paid of $0.3 million for corporate purposes; the remainder represents capital expenditures relating to the Double E Project. We assess the performance of our reportable segments based on segment adjusted EBITDA. We define segment adjusted EBITDA as total revenues less total costs and expenses; plus (i) other income excluding interest income, (ii) our proportional adjusted EBITDA for equity method investees, (iii) depreciation and amortization, (iv) adjustments related to MVC shortfall payments, (v) adjustments related to capital reimbursement activity, (vi) unit-based and noncash compensation, (vii) impairments, (viii) other noncash expenses or losses, less other noncash income or gains and (ix) restructuring expenses. We define proportional adjusted EBITDA for our equity method investees as the product of (i) total revenues less total expenses, excluding impairments and other noncash income or expense items, and amortization for deferred contract costs; and (ii) our ownership interest in Ohio Gathering during the respective period. For the purpose of evaluating segment performance, we exclude the effect of Corporate and Other revenues and expenses, such as certain general and administrative expenses (including compensation-related expenses and professional services fees), certain natural gas and crude oil marketing services, transaction costs, interest expense and income tax expense or benefit from segment adjusted EBITDA. Segment adjusted EBITDA by reportable segment follows. Three months ended March 31, 2020 2019 (In thousands) Reportable segment adjusted EBITDA Utica Shale $ 5,928 $ 6,193 Ohio Gathering 7,939 9,210 Williston Basin 16,192 18,734 DJ Basin 5,911 2,673 Permian Basin 1,581 (550 ) Piceance Basin 23,557 25,999 Barnett Shale 8,760 11,374 Marcellus Shale 5,320 5,142 Total of reportable segments’ measures of profit $ 75,188 $ 78,775 A reconciliation of income or loss before income taxes and income or loss from equity method investees to total of reportable segments’ measures of profit or loss follows. Three months ended March 31, 2020 2019 (In thousands) Reconciliation of income (loss) before income taxes and income (loss) from equity method investees to total of reportable segments’ measures of profit: Income (loss) before income taxes and income (loss) from equity method investees $ 438 $ (39,582 ) Add: Corporate and Other expense 12,077 16,650 Interest expense 23,828 22,742 Depreciation and amortization 29,900 28,153 Proportional adjusted EBITDA for equity method investees 7,939 9,210 Adjustments related to MVC shortfall payments (5,442 ) (4,199 ) Adjustments related to capital reimbursement activity (211 ) (715 ) Unit-based and noncash compensation 2,723 2,526 Loss (gain) on asset sales, net 115 (961 ) Long-lived asset impairment 3,821 44,951 Total of reportable segments’ measures of profit $ 75,188 $ 78,775 Adjustments related to MVC shortfall payments recognize the earnings from MVC shortfall payments ratably over the term of the associated MVC (see Note 3). Contributions in aid of construction are recognized over the remaining term of the respective contract. We include adjustments related to capital reimbursement activity in our calculation of segment adjusted EBITDA to account for revenue recognized from contributions in aid of construction. Adjustments related to MVC shortfall payments by reportable segment follow. Three months ended March 31, 2020 Williston Basin Piceance Basin Barnett Shale Total (In thousands) Adjustments related to expected MVC shortfall payments: $ (5,665 ) $ 223 $ — $ (5,442 ) Three months ended March 31, 2019 Williston Basin Piceance Basin Barnett Shale Total (In thousands) Adjustments related to expected MVC shortfall payments: $ (5,549 ) $ (103 ) $ 1,453 $ (4,199 )	4. SEGMENT INFORMATION As of December 31, 2019, our reportable segments are: • the Utica Shale, which is served by Summit Utica; • Ohio Gathering, which includes our ownership interest in OGC and OCC; • the Williston Basin, which is served by Polar and Divide and Bison Midstream; • the DJ Basin, which is served by Niobrara G&P; • the Permian Basin, which is served by Summit Permian; • the Piceance Basin, which is served by Grand River; • the Barnett Shale, which is served by DFW Midstream; and • the Marcellus Shale, which is served by Mountaineer Midstream. Until March 22, 2019, we owned Tioga Midstream, a crude oil, produced water and associated natural gas gathering system operating in the Williston Basin. Until December 1, 2019, we owned certain assets in the Red Rock Gathering system operating in the Piceance Basin. Refer to Note 17 to the consolidated financial statements for details on the sale of Tioga Midstream and on the sale of certain assets in the Red Rock Gathering system. Each of our reportable segments provides midstream services in a specific geographic area. Our reportable segments reflect the way in which we internally report the financial information used to make decisions and allocate resources in connection with our operations. The Ohio Gathering reportable segment includes our investment in Ohio Gathering. Income or loss from equity method investees, as reflected on the statements of operations, relates to Ohio Gathering and is recognized and disclosed on a one-month For the year ended December 31, 2019, other than the investment activity described in Note 8, Double E did not have any results of operations given that the Double E Project is currently under development. The Double E Project is expected to be operational in the third quarter of 2021. Corporate and Other represents those results that are: (i) not specifically attributable to a reportable segment; (ii) not individually reportable (such as Double E); or (iii) that have not been allocated to our reportable segments for the purpose of evaluating their performance, including certain general and administrative expense items, certain natural gas and crude oil marketing services and transaction costs. Assets by reportable segment follow. December 31, 2019 2018 2017 (In thousands) Assets (1): Utica Shale $ 206,368 $ 207,357 $ 212,311 Ohio Gathering 275,000 649,250 690,485 Williston Basin 452,152 526,819 512,860 DJ Basin 205,308 166,580 79,438 Permian Basin 185,708 145,702 57,590 Piceance Basin 631,140 699,638 719,284 Barnett Shale 350,638 376,564 383,306 Marcellus Shale 184,631 208,790 217,362 Total reportable segment assets 2,490,945 2,980,700 2,872,636 Corporate and Other 83,153 56,838 35,332 Eliminations — (4,319 ) (249 ) Total assets $ 2,574,098 $ 3,033,219 $ 2,907,719 (1) At December 31, 2019, Corporate and Other included $34.7 million relating to our investment in Double E (included in the Investment in equity method investees caption of the consolidated balance sheet). At December 31, 2018, Corporate and Other included $9.6 million of capital expenditures relating to the Double E Project. Revenues by reportable segment follow. Year ended December 31, 2019 2018 2017 (In thousands) Revenues (1): Utica Shale $ 33,991 $ 35,233 $ 38,907 Williston Basin 105,651 123,650 161,503 DJ Basin 26,050 15,294 11,860 Permian Basin 20,303 958 — Piceance Basin 133,638 155,519 154,893 Barnett Shale 71,802 68,265 71,667 Marcellus Shale 24,471 29,573 30,394 Total reportable segments revenue 415,906 428,492 469,224 Corporate and Other 30,552 88,286 26,446 Eliminations (2,930 ) (10,125 ) (6,929 ) Total revenues $ 443,528 $ 506,653 $ 488,741 (1) Excludes revenues earned by Ohio Gathering due to equity method accounting. Counterparties accounting for more than 10% of total revenues were as follows: Year ended December 31, 2019 2018 2017 Percentage of total revenues (1): Counterparty A - Piceance Basin 11 % * * Counterparty B - Williston Basin 10 % * 13 % Counterparty C - Piceance Shale * 10 % * (1) Excludes revenues earned by Ohio Gathering due to equity method accounting. * Less than 10% Depreciation and amortization, including the amortization expense associated with our favorable and unfavorable (for 2018) gas gathering contracts as reported in other revenues, by reportable segment follows. Year ended December 31, 2019 2018 2017 (In thousands) Depreciation and amortization (1): Utica Shale $ 7,659 $ 7,672 $ 7,009 Williston Basin 19,829 22,642 33,772 DJ Basin 3,732 3,133 2,636 Permian Basin 4,868 243 — Piceance Basin 47,018 46,919 46,289 Barnett Shale (2) 16,575 15,325 15,001 Marcellus Shale 9,141 9,090 9,047 Total reportable segment depreciation and amortization 108,822 105,024 113,754 Corporate and Other 2,752 1,906 1,364 Total depreciation and amortization $ 111,574 $ 106,930 $ 115,118 (1) Excludes depreciation and amortization recognized by Ohio Gathering due to equity method accounting. (2) Includes the amortization expense associated with our favorable and unfavorable (for 2018) gas gathering contracts as reported in Other revenues. Cash paid for capital expenditures by reportable segment follow. Year ended December 31, 2019 2018 2017 (In thousands) Cash paid for capital expenditures (1): Utica Shale $ 3,902 $ 5,719 $ 22,921 Williston Basin 30,861 25,202 17,309 DJ Basin 80,487 64,920 7,150 Permian Basin 44,955 83,823 56,020 Piceance Basin 1,946 7,887 16,564 Barnett Shale (2) 184 1,370 569 Marcellus Shale 693 1,030 641 Total reportable segment capital expenditures 163,028 189,951 121,174 Corporate and Other 19,263 10,635 3,041 Total cash paid for capital expenditures $ 182,291 $ 200,586 $ 124,215 (1) Excludes cash paid for capital expenditures by Ohio Gathering due to equity method accounting. (2) For the year ended December 31, 2019, the amount includes sales tax reimbursements of $1.1 million. For the years ended December 31, 2019 and 2018, Corporate and Other includes cash paid of $1.6 million and $3.3 million, respectively, for corporate purposes; the remainder represents capital expenditures relating to the Double E Project. We assess the performance of our reportable segments based on segment adjusted EBITDA. We define segment adjusted EBITDA as total revenues less total costs and expenses; plus (i) other income excluding interest income, (ii) our proportional adjusted EBITDA for equity method investees, (iii) depreciation and amortization, (iv) adjustments related to MVC shortfall payments, (v) adjustments related to capital reimbursement activity, (vi) unit-based and noncash compensation, (vii) impairments (viii) other noncash expenses or losses, less other noncash income or gains and (ix) restructuring expenses. We define proportional adjusted EBITDA for our equity method investees as the product of (i) total revenues less total expenses, excluding impairments and other noncash income or expense items, and amortization for deferred contract costs; and (ii) our ownership interest in Ohio Gathering during the respective period. For the purpose of evaluating segment performance, we exclude the effect of Corporate and Other revenues and expenses, such as certain general and administrative expenses (including compensation-related expenses and professional services fees), certain natural gas and crude oil marketing services, transaction costs, interest expense and income tax expense or benefit from segment adjusted EBITDA. Segment adjusted EBITDA by reportable segment follows. Year ended December 31, 2019 2018 2017 (In thousands) Reportable segment adjusted EBITDA Utica Shale $ 29,292 $ 30,285 $ 34,011 Ohio Gathering 39,126 39,969 41,246 Williston Basin 69,437 76,701 66,413 DJ Basin 18,668 7,558 6,624 Permian Basin (879 ) (1,200 ) — Piceance Basin 98,765 111,042 111,113 Barnett Shale 43,043 43,268 46,232 Marcellus Shale 20,051 24,267 23,888 Total of reportable segments’ measures of profit $ 317,503 $ 331,890 $ 329,527 A reconciliation of income or loss before income taxes and income or loss from equity method investees to total of reportable segments’ measures of profit or loss follows. Year ended December 31, 2019 2018 2017 (In thousands) Reconciliation of (loss) income before income taxes and loss from equity method investees to total of reportable segments’ measures of profit: (Loss) income before income taxes and loss from equity method investees $ (54,644 ) $ 45,575 $ (134,187 ) Add: Corporate and Other expense 44,808 45,131 40,803 Interest expense 91,966 82,830 88,701 Early extinguishment of debt — — 22,039 Depreciation and amortization 111,574 106,930 115,118 Proportional adjusted EBITDA for equity method investees 39,126 39,969 41,246 Adjustments related to MVC shortfall payments 3,476 (3,632 ) (41,373 ) Adjustments related to capital reimbursement activity (2,156 ) (427 ) — Unit-based and noncash compensation 8,171 8,328 7,951 (Gain) loss on asset sales, net (1,536 ) — 527 Long-lived asset impairment 60,507 7,186 188,702 Goodwill impairment 16,211 — — Total of reportable segments’ measures of profit $ 317,503 $ 331,890 $ 329,527 For the years ended December 31, 2019 and 2018, adjustments related to MVC shortfall payments recognize the earnings from MVC shortfall payments ratably over the term of the associated MVC (see Note 3). Contributions in aid of construction are recognized over the remaining term of the respective contract. We include adjustments related to capital reimbursement activity in our calculation of segment adjusted EBITDA to account for revenue recognized from contributions in aid of construction. For the year ended December 31, 2017, we included adjustments related to MVC shortfall payments in our calculation of segment adjusted EBITDA to account for (i) the net increases or decreases in deferred revenue for MVC shortfall payments and (ii) our inclusion of expected annual MVC shortfall payments. With respect to the impact of a net change in deferred revenue for MVC shortfall payments, we treated increases in deferred revenue balances as a favorable adjustment to segment adjusted EBITDA, while decreases in deferred revenue balances were treated as an unfavorable adjustment to segment adjusted EBITDA. We also included a proportional amount of any historical and expected MVC shortfall payments in each quarter prior to the quarter in which we actually recognize the shortfall payment. Adjustments related to MVC shortfall payments by reportable segment follow. Year ended December 31, 2019 Williston Basin Piceance Basin Barnett Shale Total (In thousands) Adjustments related to expected MVC shortfall payments: $ — $ (103 ) $ 3,579 $ 3,476 Year ended December 31, 2018 Williston Basin Piceance Basin Barnett Shale Total (In thousands) Adjustments related to expected MVC shortfall payments: $ — $ 10 $ (3,642 ) $ (3,632 ) Year Ended December 31, 2017 Williston Basin Piceance Basin Barnett Shale Total (In thousands) Adjustments related to MVC shortfall payments: Net change in deferred revenue for MVC shortfall payments $ (37,693 ) $ (3,065 ) $ — $ (40,758 ) Expected MVC shortfall adjustments — (3 ) (612 ) (615 ) Total adjustments related to MVC shortfall payments $ (37,693 ) $ (3,068 ) $ (612 ) $ (41,373 )

PROPERTY, PLANT, AND EQUIPMENT,

PROPERTY, PLANT, AND EQUIPMENT, NET	3 Months Ended	12 Months Ended
PROPERTY, PLANT, AND EQUIPMENT, NET	Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT, AND EQUIPMENT, NET	5. PROPERTY, PLANT AND EQUIPMENT, NET Details on property, plant and equipment follow. March 31, 2020 December 31, 2019 (In thousands) Gathering and processing systems and related equipment $ 2,193,225 $ 2,182,950 Construction in progress 73,040 78,716 Land and line fill 10,440 10,137 Other 59,014 54,595 Total 2,335,719 2,326,398 Less accumulated depreciation 465,636 443,909 Property, plant and equipment, net $ 1,870,083 $ 1,882,489 In March 2020, in connection with the cancellation of a compressor station project in the DJ Basin due to delays in customer drilling plans, we recorded an impairment charge of $3.6 million for the related soft project costs. In March 2019, certain events occurred which indicated that certain long-lived assets in the DJ Basin and Barnett Shale reporting segments could be impaired. Consequently, in the first quarter of 2019, we performed a recoverability assessment of certain assets within these reporting segments. Also in March 2019, in the DJ Basin we determined that certain processing plant assets related to our existing 20 MMcf/d plant would no longer be utilized due to our expansion plans for the Niobrara G&P system. Based on the results of the recoverability assessment and the conclusion that the carrying value was not fully recoverable, we recorded an impairment charge of $34.7 million related to these assets in the first quarter of 2019. In March 2019, in the Barnett Shale we determined that certain compressor station assets would be shut down and decommissioned. As a result, we recorded an impairment charge of $9.7 million related to these assets in the first quarter of 2019. See Note 6 for additional details. Depreciation expense and capitalized interest follow. Three months ended March 31, 2020 2019 (In thousands) Depreciation expense $ 21,698 $ 19,820 Capitalized interest 491 1,915	5. PROPERTY, PLANT AND EQUIPMENT, NET Details on property, plant and equipment follow. December 31, 2019 December 31, 2018 (In thousands) Gathering and processing systems and related equipment $ 2,182,950 $ 2,155,325 Construction in progress 78,716 137,920 Land and line fill 10,137 11,748 Other 54,595 47,319 Total 2,326,398 2,352,312 Less accumulated depreciation 443,909 388,213 Property, plant and equipment, net $ 1,882,489 $ 1,964,099 During 2019, 2018 and 2017, we identified certain events, facts and circumstances which indicated that certain of our property, plant and equipment could be impaired. As such, we reviewed the assets that had been identified as potentially impaired and estimated the fair value of the identified property, plant and equipment using a market-based approach. In December 2019, we sold certain Red Rock Gathering system assets for a cash purchase price of $12.0 million. Prior to closing, we recorded an impairment charge of $14.2 million based on the expected consideration and the carrying value for the Red Rock Gathering system assets. See Note 17 for additional details. In December 2019, in connection with the cancellation of a project, we determined certain processing plant assets in the Permian Basin would no longer be utilized. As a result, we recorded an impairment charge of $0.7 million related to these assets in the fourth quarter of 2019. See Note 6 for additional details. In March 2019, certain events occurred which indicated that certain long-lived assets in the DJ Basin and Barnett Shale reporting segments could be impaired. Consequently, in the first quarter of 2019, we performed a recoverability assessment of certain assets within these reporting segments. In the DJ Basin, we determined that certain processing plant assets related to our existing 20 MMcf/d plant would no longer be utilized due to our expansion plans for the Niobrara G&P system. Based on the results of the recoverability assessment and the conclusion that the carrying value was not fully recoverable, we recorded an impairment charge of $34.7 million related to these assets in the first quarter of 2019. In the Barnett Shale, we determined, in the first quarter of 2019, that certain compressor station assets would be shut down and decommissioned. As a result, we recorded an impairment charge of $9.7 million related to these assets in the first quarter of 2019. See Note 6 for additional details. In December 2018, in connection with certain strategic initiatives, we performed a recoverability assessment of certain assets within the Williston Basin reporting segment. Based on the results, we concluded that the carrying value of certain long-lived assets related to the Tioga Midstream system within the Williston Basin were not fully recoverable. We recorded an impairment charge of $3.9 million related to these assets after comparing the fair value of the long-lived assets to their carrying values. In addition, we reviewed the other assets that had been identified as potentially impaired and recognized the long-lived asset impairments in the table below. In December 2017, in connection with certain strategic initiatives, we performed a financial review of certain assets within the Williston Basin reporting segment. This resulted in a triggering event that required us to perform a recoverability test. Based on the results of the test, we concluded that the carrying value of certain long-lived assets related to the Bison Midstream system within the Williston Basin were not fully recoverable. We recorded an impairment charge of $101.9 million related to these assets after comparing the fair value of the long-lived assets to their carrying values. See Note 6 for additional details. During 2019, 2018 and 2017, we recognized the following long-lived asset impairments, by segment. Year ended December 31, 2019 2018 2017 (In thousands) Long-lived asset impairment: Williston Basin $ 10 $ 3,972 $ 101,961 Piceance Basin 14,162 1,004 697 DJ Basin 34,913 9 — Barnett Shale 9,629 — — Utica Shale — 1,440 878 Permian Basin 726 761 — Our impairment determinations, in the context of these reviews, involved significant assumptions and judgments. Differing assumptions regarding any of these inputs could have a significant effect on the various valuations. As such, the fair value measurements utilized within these estimates are classified as non-recurring Depreciation expense and capitalized interest follow. Year ended December 31, 2019 2018 2017 (In thousands) Depreciation expense $ 78,489 $ 74,674 $ 75,382 Capitalized interest 6,974 8,497 2,579

AMORTIZING INTANGIBLE ASSETS

AMORTIZING INTANGIBLE ASSETS	3 Months Ended	12 Months Ended
AMORTIZING INTANGIBLE ASSETS	Mar. 31, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
AMORTIZING INTANGIBLE ASSETS	6. AMORTIZING INTANGIBLE ASSETS Details regarding our intangible assets, all of which are subject to amortization, follow: March 31, 2020 Gross carrying Accumulated Net (In thousands) Favorable gas gathering contracts $ 24,195 $ (15,359 ) $ 8,836 Contract intangibles 278,448 (175,973 ) 102,475 Rights-of-way 157,175 (44,410 ) 112,765 Total intangible assets $ 459,818 $ (235,742 ) $ 224,076 December 31, 2019 Gross carrying Accumulated Net (In thousands) Favorable gas gathering contracts $ 24,195 $ (15,125 ) $ 9,070 Contract intangibles 278,448 (169,549 ) 108,899 Rights-of-way 157,175 (42,866 ) 114,309 Total intangible assets $ 459,818 $ (227,540 ) $ 232,278 In March 2019, certain events occurred which indicated that certain long-lived assets relating to the Barnett Shale reporting segment could be impaired (see Note 5). In connection with this evaluation, we evaluated the related intangible assets associated therewith for impairment consisting of rights-of-way rights-of-way We recognized amortization expense in Other revenues as follows: Three months ended March 31, 2020 2019 (In thousands) Amortization expense – favorable gas gathering contracts $ (234 ) $ (389 ) We recognized amortization expense in costs and expenses as follows: Three months ended March 31, 2020 2019 (In thousands) Amortization expense – contract intangibles $ 6,424 $ 6,397 Amortization expense – rights-of-way 1,544 1,547 The estimated aggregate annual amortization expected to be recognized for the remainder of 2020 and each of the four succeeding fiscal years follows. Intangible assets (In thousands) 2020 $ 23,926 2021 28,209 2022 25,142 2023 25,088 2024 14,917	6. AMORTIZING INTANGIBLE ASSETS Details regarding our intangible assets, all of which are subject to amortization, follow. December 31, 2019 Gross carrying Accumulated Net (In thousands) Favorable gas gathering contracts $ 24,195 $ (15,125 ) $ 9,070 Contract intangibles 278,448 (169,549 ) 108,899 Rights-of-way 157,175 (42,866 ) 114,309 Total intangible assets $ 459,818 $ (227,540 ) $ 232,278 December 31, 2018 Gross carrying Accumulated Net (In thousands) Favorable gas gathering contracts $ 24,195 $ (13,905 ) $ 10,290 Contract intangibles 278,448 (143,962 ) 134,486 Rights-of-way 166,209 (37,569 ) 128,640 Total intangible assets $ 468,852 $ (195,436 ) $ 273,416 In December 2019, in connection with the cancellation of a project, we determined certain rights-of-way Also in early 2019, certain events occurred which indicated that certain long-lived assets relating to the Barnett Shale reporting segment could be impaired (see Note 5). In connection with this evaluation, we evaluated the related intangible assets associated therewith for impairment consisting of rights-of-way rights-of-way In December 2017, in connection with certain strategic initiatives, we evaluated certain long-lived assets relating to the Bison Midstream system within the Williston Basin reporting segment (see Note 5). In connection with this evaluation, we evaluated the related intangible assets associated therewith for impairment consisting of contract intangible assets and rights-of-way We recognized amortization expense in Other revenues as follows: Year ended December 31, 2019 2018 2017 (In thousands) Amortization expense – favorable gas gathering contracts $ (1,220 ) $ (1,555 ) $ (1,555 ) We recognized amortization expense in costs and expenses as follows: Year ended December 31, 2019 2018 2017 (In thousands) Amortization expense – contract intangibles $ 25,587 $ 26,141 $ 34,202 Amortization expense – rights-of-way 6,278 6,448 6,153 The estimated aggregate annual amortization expected to be recognized for as of December 31, 2019 for each of the five succeeding fiscal years follows. Intangible assets (In thousands) 2020 $ 31,901 2021 28,209 2022 25,142 2023 25,088 2024 14,917

GOODWILL

GOODWILL	12 Months Ended
GOODWILL	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL	7. GOODWILL Goodwill for the year ended December 31, 2018 of $16.2 million was related to the acquisition of the Mountaineer Midstream system in 2013. Accumulated goodwill impairments by reportable segment for those reporting units that have previously recognized goodwill follow. Year ended December 31, 2019 2018 2017 (In thousands) Accumulated goodwill impairment: Piceance Basin $ 45,478 $ 45,478 $ 45,478 Williston Basin 257,572 257,572 257,572 Marcellus Shale 16,211 — — Total accumulated goodwill impairment $ 319,261 $ 303,050 $ 303,050 We evaluate goodwill whenever events or circumstances indicate that it is more likely than not that the fair value of a reporting unit is less than its carrying value, including goodwill. If the reporting unit’s fair value exceeds its carrying value, including goodwill, we conclude that the goodwill of the reporting unit has not been impaired and no further work is performed. If we determine that the reporting unit’s carrying value, including goodwill, exceeds its fair value, we recognize the excess of the carrying value over the fair value as a goodwill impairment loss. We performed our annual goodwill impairment testing for the Mountaineer Midstream reporting unit as of September 30, 2019 using a combination of the income and market approaches. We determined that the fair value of the Mountaineer Midstream reporting unit did not exceed its carrying value, including goodwill. As a result, we recognized a goodwill impairment charge of $16.2 million for the year ended December 31, 2019. We had no impairments of goodwill for the years ended December 31, 2018 and 2017. Fair Value Measurement. non-recurring

EQUITY METHOD INVESTMENTS

EQUITY METHOD INVESTMENTS	3 Months Ended	12 Months Ended
EQUITY METHOD INVESTMENTS	Mar. 31, 2020	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
EQUITY METHOD INVESTMENTS	7. EQUITY METHOD INVESTMENTS Double E In June 2019, we formed Double E in connection with the Double E Project. Effective June 26, 2019, Summit Permian Transmission, a wholly owned and consolidated subsidiary of the Partnership, and an affiliate of Double E’s foundation shipper (the “JV Partner”) executed an agreement whereby Double E will provide natural gas transportation services from multiple receipt points in the Delaware Basin to various delivery points in and around the Waha Hub in Texas (the “Double E Agreement”). Concurrent with the Double E Agreement, we issued a parental guaranty to fund any capital calls not satisfied by Summit Permian Transmission during the construction of the Double E Project, for an amount not to exceed $350.0 million. The Partnership has guaranteed, among other things, payment of our pro rata share of the required capital calls during construction of the Double E Project and, as of March 31, 2020, we estimate that our pro rata share of our remaining capital contributions is approximately $251 million. In connection with the Double E Agreement and the related Double E Project, the Partnership contributed total assets of approximately $23.6 million in exchange for a 70% ownership interest in Double E and our JV Partner contributed $7.3 million of cash in exchange for a 30% ownership interest in Double E. Concurrent with these contributions, and in accordance with the Double E Agreement, Double E distributed $7.3 million to the Partnership. Subsequent to the formation of Double E, we made additional cash investments of $18.3 million through December 31, 2019. During the three months ended March 31, 2020, we made cash investments of $58.0 million in the Double E Project. Upon completion of the Double E Project, we expect to own at least a 50% interest in the Double E Project. We are leading the development, permitting and construction of the Double E Project and expect to operate the pipeline upon commissioning. At our current 70% interest, we estimate that our total share of the capital expenditures required to develop the Double E Project will total approximately $350.0 million. Double E is deemed to be a variable interest entity as defined in GAAP. As of the date of the Double E Agreement, Summit Permian Transmission was not deemed to be the primary beneficiary due to the JV Partner’s voting rights on significant matters. We account for our ownership interest in Double E as an equity method investment because we have significant influence over Double E. Our portion of Double E’s net assets, which was $92.3 million at March 31, 2020, is reported under the caption Investment in equity method investees on the unaudited condensed consolidated balance sheet. For the three months ended March 31, 2020, other than the investment activity noted above, Double E did not have any results of operations given that the Double E Project is currently under development. Ohio Gathering Ohio Gathering owns and operates midstream infrastructure consisting of a liquids-rich natural gas gathering system, a dry natural gas gathering system and a condensate stabilization facility in the Utica Shale in southeastern Ohio. Ohio Gathering provides gathering services pursuant to primarily long-term, fee-based As of March 31, 2020 and December 31, 2019, our ownership interest in Ohio Gathering was 38.5%. A reconciliation of our 38.5% ownership interest in Ohio Gathering to our investment per Ohio Gathering’s books and records follows (in thousands). Investment in Ohio Gathering, March 31, 2020 $ 271,268 March cash distributions 1,875 Basis difference 223,151 Investment in Ohio Gathering February 29, 2020 $ 496,294 As noted in our 2019 Annual Report, in December 2019 an impairment loss of long-lived assets was recognized by OCC which brought our investment in OCC to zero. As a result, we have not recorded our portion of OCC’s net loss for the three months ended March 31, 2020 in the Income (loss) from equity method investees caption of our unaudited condensed consolidated statements of operations. Summarized statements of operations information for OGC and Three months ended February 29, 2020 Three months ended February 28, 2019 OGC OCC OGC OCC (In thousands) Total revenues $ 30,068 $ 2,727 $ 33,466 $ 2,266 Total operating expenses 25,750 30,855 25,487 2,973 Net income (loss) 4,311 (28,128 ) 7,972 (707 )	8. EQUITY METHOD INVESTMENTS Double E In June 2019, we formed Double E in connection with the Double E Project. Effective June 26, 2019, Summit Permian Transmission, a wholly owned and consolidated subsidiary of the Partnership, and our JV Partner executed the Agreement whereby Double E will provide natural gas transportation services from multiple receipt points in the Delaware Basin to various delivery points in and around the Waha Hub in Texas. Concurrent with the Agreement, we issued a parental guaranty to fund any capital calls not satisfied by Summit Permian Transmission during the construction of Double E, for an amount not to exceed $350.0 million. At December 31, 2019, our outstanding parental guaranty for Double E was $308.9 million. In connection with the Agreement and the related Double E Project, the Partnership contributed total assets of approximately $23.6 million in exchange for a 70% ownership interest in Double E and our JV Partner contributed $7.3 million of cash in exchange for a 30% ownership interest in Double E. Concurrent with these contributions, and in accordance with the Agreement, Double E distributed $7.3 million to the Partnership. Subsequent to the formation of Double E, we also made additional cash investments of $18.3 million through December 2019. Double E is deemed to be a variable interest entity as defined in GAAP. As of the date of the Agreement, Summit Permian Transmission was not deemed to be the primary beneficiary due to the JV Partner’s voting rights on significant matters. We account for our ownership interest in Double E as an equity method investment because we have significant influence over Double E. Our portion of Double E’s net assets, which was $34.7 million at December 31, 2019, is reported under the caption Investment in equity method investees on the consolidated balance sheet. For the year ended December 31, 2019, other than the investment activity noted above, Double E did not have any results of operations given that the Double E Project is currently under development. Ohio Gathering Ohio Gathering owns, operates and is currently developing midstream infrastructure consisting of a liquids-rich natural gas gathering system, a dry natural gas gathering system and a condensate stabilization facility in the Utica Shale in southeastern Ohio. Ohio Gathering provides gathering services pursuant to primarily long-term, fee-based Our initial investment in Ohio Gathering in 2014 included a $190.0 million payment to acquire a 1% interest from a third party, which included an option to increase our ownership to 40%, as well as a series of contributions directly to Ohio Gathering in 2014, which increased our ownership to 40%. Concurrent with and subsequent to the exercise of the option, the non-affiliated “Non-affiliated We account for our ownership interests in Ohio Gathering as an equity method investment because we have joint control with the Non-affiliated We recognized the $190.0 million paid for the initial 1% interest as an investment in Ohio Gathering at inception. In addition, Ohio Gathering assigned a value of $7.5 million to the exercise option, which it ultimately attributed to our capital account. Neither of the aforementioned transactions involved a flow of funds to or from Ohio Gathering. As such, they created a basis difference between our recorded investment in equity method investees and the amount attributed to us by Ohio Gathering within its financial statements. In December 2019, we identified certain triggering events which indicated that our equity method investment in Ohio Gathering could be impaired. In accordance with ASC Topic 323, we completed an equity method impairment analysis to determine the equity method impairment charge to be recorded on our consolidated financial statements resulting from an other-than-temporary impairment. As a result of our analysis, an impairment charge of approximately $329.7 million was recorded in 2019 in Loss from equity method investments on the accompanying consolidated statements of operations. The fair value of our investment in Ohio Gathering was determined based upon applying the discounted cash flow method, which is an income approach, and the guideline public company method, which is a market approach. The discounted cash flow fair value estimate is based on known or knowable information at the measurement date. The significant assumptions that were used to develop the estimate of the fair value under the discounted cash flow method include management’s best estimates of the expected future results using a probability weighted average set of cash flow forecasts and a discount rate of approximately 9.0 percent. Fair value determinations require considerable judgment and are sensitive to changes in underlying assumptions and factors. As such, the fair value of the Ohio Gathering equity method investment represents a Level 3 measurement. As a result, actual results may differ from the estimates and assumptions made for purposes of this impairment analysis. Also in December 2019, an impairment loss of long-lived assets was recognized by OCC. Although we recognize activity for Ohio Gathering on a one-month In December 2018, Ohio Gathering was involved in legal proceedings relating to a dispute regarding pipeline right of way rights and associated trespass claims that took place prior to December 31, 2018. Ohio Gathering received a judgment on those proceedings in January 2019 and recorded an estimate of the legal exposure as of December 31, 2018. Although we recognize activity for Ohio Gathering on a one-month As a result of our joint venture partner funding a disproportionate amount of the capital calls during the year ended December 31, 2019, our ownership interest in Ohio Gathering decreased from 40.0% at December 31, 2018, to 38.5% at December 31, 2019. A reconciliation of our 38.5% and 40% ownership interest in Ohio Gathering to our investment per Ohio Gathering’s books and records follows for the years ending December 31, 2019 and 2018, respectively (in thousands). 2019 2018 (In thousands) Investment in Ohio Gathering, December 31 $ 275,000 $ 649,250 December cash distributions 2,700 2,736 Impairment loss (1) 232,521 5,652 Loss contingency — 2,040 Basis difference — (116,832 ) Investment in Ohio Gathering, net of basis difference, November 30 $ 510,221 $ 542,846 (1) Amount is comprised of (i) a $329.7 million impairment of our equity method investment in Ohio Gathering; (ii) the write-off Summarized balance sheet information for OGC and OCC follows (amounts represent 100% of investee financial information). November 30, 2019 November 30, 2018 OGC OCC OGC OCC (In thousands) Current assets $ 41,972 $ 2,187 $ 37,403 $ 3,716 Noncurrent assets 1,281,171 28,323 1,262,253 27,203 Total assets $ 1,323,143 $ 30,510 $ 1,299,656 $ 30,919 Current liabilities $ 21,798 $ 4,016 $ 19,903 $ 3,912 Noncurrent liabilities 4,113 6,683 3,688 8,807 Total liabilities $ 25,911 $ 10,699 $ 23,591 $ 12,719 Summarized statements of operations information for OGC and OCC follow (amounts represent 100% of investee financial information). Twelve months ended November 30, 2019 Twelve months ended November 30, 2018 Twelve months ended November 30, 2017 OGC OCC OGC OCC OGC OCC (In thousands) Total revenues $ 142,138 $ 8,601 $ 142,398 $ 10,177 $ 140,679 $ 8,607 Total operating expenses 108,234 38,815 136,722 9,053 111,897 8,298 Net income (loss) 33,897 (30,214 ) 5,670 498 28,785 (907 )

DEFERRED REVENUE

DEFERRED REVENUE	3 Months Ended	12 Months Ended
DEFERRED REVENUE	Mar. 31, 2020	Dec. 31, 2019
Revenue From Contract With Customer [Abstract]
DEFERRED REVENUE	8. DEFERRED REVENUE A rollforward of current deferred revenue follows. Utica Williston DJ Basin Piceance Basin Barnett Marcellus Total (In thousands) Current deferred revenue, January 1, 2020 $ 18 $ 1,933 $ 2,860 $ 7,014 $ 1,630 $ 38 $ 13,493 Additions 2 483 2,123 1,547 396 9 4,560 Less revenue recognized 5 483 1,285 1,544 409 9 3,735 Current deferred revenue, March 31, 2020 $ 15 $ 1,933 $ 3,698 $ 7,017 $ 1,617 $ 38 $ 14,318 A rollforward of noncurrent deferred revenue follows. Utica Williston DJ Piceance Basin Barnett Marcellus Total (In thousands) Noncurrent deferred revenue, January 1, 2020 $ 3 $ 3,634 $ 7,589 $ 17,710 $ 9,575 $ 198 $ 38,709 Additions 425 3,522 3,263 1,304 382 — 8,896 Less reclassification to current deferred revenue 2 483 2,123 1,547 396 9 4,560 Noncurrent deferred revenue, March 31, 2020 $ 426 $ 6,673 $ 8,729 $ 17,467 $ 9,561 $ 189 $ 43,045	9. DEFERRED REVENUE Certain of our gathering and/or processing agreements provide for monthly or annual MVCs. The amount of the shortfall payment is based on the difference between the actual throughput volume shipped and/or processed for the applicable period and the MVC for the applicable period, multiplied by the applicable gathering or processing fee. Many of our gas gathering agreements contain provisions that can reduce or delay the cash flows that we expect to receive from our MVCs to the extent that a customer’s actual throughput volumes are above or below its MVC for the applicable contracted measurement period. These provisions include the following: • To the extent that a customer’s throughput volumes are less than its MVC for the applicable period and the customer makes a shortfall payment, it may be entitled to an offset in one or more subsequent periods to the extent that its throughput volumes in subsequent periods exceed its MVC for those periods. In such a situation, we would not receive gathering fees on throughput in excess of that customer’s MVC (depending on the terms of the specific gas gathering agreement) to the extent that the customer had made a shortfall payment with respect to one or more preceding measurement periods (as applicable). • To the extent that a customer’s throughput volumes exceed its MVC in the applicable contracted measurement period, it may be entitled to apply the excess throughput against its aggregate MVC, thereby reducing the period for which its annual MVC applies. As a result of this mechanism, the weighted-average remaining period for which our MVCs apply will be less than the weighted-average of the original stated contract terms of our MVCs. • To the extent that certain of our customers’ throughput volumes exceed its MVC for the applicable period, there is a crediting mechanism that allows the customer to build a bank of credits that it can utilize in the future to reduce shortfall payments owed in subsequent periods, subject to expiration if there is no shortfall in subsequent periods. The period over which this credit bank can be applied to future shortfall payments varies, depending on the particular gas gathering agreement. A rollforward of current deferred revenue follows. Utica Shale Williston DJ Basin Piceance Basin Barnett Marcellus Total (In thousands) Current deferred revenue, January 1, 2018 $ 18 $ 1,017 $ 358 $ 7,038 $ 1,619 $ 38 $ 10,088 Additions 18 1,744 943 21,955 1,651 96 26,407 Less revenue recognized 18 1,347 562 21,377 1,628 96 25,028 Current deferred revenue, December 31, 2018 18 1,414 739 7,616 1,642 38 11,467 Additions 18 2,262 5,165 16,211 1,632 38 25,326 Less revenue recognized 18 1,743 3,044 16,813 1,644 38 23,300 Current deferred revenue, December 31, 2019 $ 18 $ 1,933 $ 2,860 $ 7,014 $ 1,630 $ 38 $ 13,493 A rollforward of noncurrent deferred revenue follows. Utica Shale Williston DJ Basin Piceance Basin Barnett Marcellus Total (In thousands) Noncurrent deferred, revenue, January 1, 2018 $ 39 $ 4,215 $ 4,505 $ 18,219 $ 8,217 $ 333 $ 35,528 Additions — 1,851 3,720 7,869 3,062 — 16,502 Less reclassification to current deferred revenue 18 1,673 941 8,146 1,651 97 12,526 Noncurrent deferred revenue, December 31, 2018 21 4,393 7,284 17,942 9,628 236 39,504 Additions — 1,940 5,470 6,104 1,579 — 15,093 Less reclassification to current deferred revenue 18 2,699 5,165 6,336 1,632 38 15,888 Noncurrent deferred revenue, December 31, 2019 $ 3 $ 3,634 $ 7,589 $ 17,710 $ 9,575 $ 198 $ 38,709

DEBT

DEBT	3 Months Ended	12 Months Ended
DEBT	Mar. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
DEBT	9. DEBT Debt consisted of the following: March 31, 2020 December 31, 2019 (In thousands) Summit Holdings’ variable rate senior secured Revolving Credit Facility (3.74% at March 31, 2020 and 4.55% at December 31, 2019) due May 2022 $ 698,000 $ 677,000 Summit Holdings’ 5.5% senior unsecured notes due August 2022 300,000 300,000 Less unamortized debt issuance costs (1) (1,521 ) (1,686 ) Summit Holdings’ 5.75% senior unsecured notes due April 2025 500,000 500,000 Less unamortized debt issuance costs (1) (4,763 ) (5,015 ) SMP Holdings’ variable rate senior secured term loan (7.00% at March 31, 2020 and 7.80% at December 31, 2019) due May 2022 160,750 161,500 Less unamortized debt issuance costs (1) (3,601 ) (3,974 ) Total debt 1,648,865 1,627,825 Less current portion 7,800 5,546 Total long-term debt $ 1,641,065 $ 1,622,279 (1) Issuance costs are being amortized over the life of the Term Loan B and Senior Notes. Revolving Credit Facility. Borrowings under the Revolving Credit Facility bear interest, at the election of Summit Holdings, at a rate based on the alternate base rate (as defined in the credit agreement) plus an applicable margin ranging from 0.75% to 1.75% or the adjusted Eurodollar rate, as defined in the credit agreement, plus an applicable margin ranging from 1.75% to 2.75%, with the commitment fee ranging from 0.30% to 0.50% in each case based on our relative leverage at the time of determination. At March 31, 2020, the applicable margin under LIBOR borrowings was 2.75%, the interest rate was 3.74% and the unused portion of the Revolving Credit Facility totaled $542.9 million, subject to a commitment fee of 0.50%, after giving effect to the issuance thereunder of a $9.1 million outstanding but undrawn irrevocable standby letter of credit. Based on covenant limits, our available borrowing capacity under the Revolving Credit Facility as of March 31, 2020 was approximately $120 million. See Note 15 for additional information on our letter of credit. As of March 31, 2020, we had $5.5 million of debt issuance costs attributable to our Revolving Credit Facility and related amendments which are included in Other noncurrent assets on the unaudited condensed consolidated balance sheet. As of and during the three months ended March 31, 2020, we were in compliance with the Revolving Credit Facility’s financial covenants. There were no defaults or events of default during the three months ended March 31, 2020. Senior Notes. “Co-Issuers”) co-issued In February 2017, the Co-Issuers The Guarantor Subsidiaries are 100% owned by a subsidiary of SMLP. The Guarantor Subsidiaries and SMLP fully and unconditionally and jointly and severally guarantee the Senior Notes. There are no significant restrictions on the ability of SMLP or Summit Holdings to obtain funds from its subsidiaries by dividend or loan. Finance Corp. has had no assets or operations since inception in 2013. We have no other independent assets or operations. At no time have the Senior Notes been guaranteed by the Co-Issuers. As of and during the three months ended March 31, 2020, we were in compliance with the covenants governing our Senior Notes. There were no defaults or events of default during the three months ended March 31, 2020. SMP Holdings Term Loan. At March 31, 2020, the Term Loan B is secured by the following collateral): (i) a perfected first-priority lien on, and pledge of (A) all of the capital stock issued by SMP Holdings, (B) 34.6 million SMLP units owned by SMP Holdings (see Note 12), (C) all of the equity interests owned by SMP Holdings in Summit Midstream GP, LLC, which is the general partner of SMLP, and (ii) substantially all other personal property of SMP Holdings. SMP Holdings is required to repay principal amounts outstanding under the Term Loan B quarterly, based on a fixed amortization schedule and to prepay its debt obligations based on an excess cash flow calculation for the applicable fiscal quarter which is determined in accordance with the terms of the Term Loan B credit agreement. The Company’s current portion of long-term debt, which includes scheduled principal amortization and excess cash flow prepayments, includes $4.8 million with respect to its fourth quarter 2019 and first quarter 2020 required excess cash flow payments which will be paid within the second quarter of 2020. We have not included an estimated excess cash flow amount in the current portion of long-term debt relating to the second, third and fourth quarter of 2020 because the amount is not currently estimable given that the excess cash flow calculation is based on the occurrence of future events. As of March 31, 2020, the Company was in compliance the Term Loan B’s financial covenants. There were no defaults or events of default during the three months ended March 31, 2020.	10. DEBT Debt consisted of the following: December 31, 2019 December 31, 2018 (In thousands) Summit Holdings’ variable rate senior secured ( $ 677,000 $ 466,000 Summit Holdings’ 5.5% senior unsecured notes due August 2022 300,000 300,000 Less unamortized debt issuance costs (1) (1,686 ) (2,362 ) Summit Holdings’ 5.75% senior unsecured notes due April 2025 500,000 500,000 Less unamortized debt issuance costs (1) (5,015 ) (5,907 ) SMP Holdings’ variable rate senior secured term loan ( 161,500 226,750 Less unamortized debt issuance costs (1) (3,974 ) (5,701 ) Total debt 1,627,825 1,478,780 Less current portion 5,546 14,500 Total long-term debt $ 1,622,279 $ 1,464,280 (1) Issuance costs are being amortized over the life of the Term Loan B The aggregate amount of debt maturing during each of the years after December 31, 2019 are as follows (in thousands): 2020 $ — 2021 — 2022 1,138,500 2023 — 2024 — Thereafter 500,000 Total long-term debt $ 1,638,500 Revolving Credit Facility. In May 2017, Summit Holdings amended and restated its Revolving Credit Facility with a third amended and restated credit agreement which: (i) maintained the Revolving Credit Facility commitments of $1.25 billion, (ii) extended the maturity from November 2018 to May 2022, (iii) included a $250.0 million accordion feature, (iv) maintained the same leverage-based pricing and commitment fee grid, (v) increased the maximum permitted total leverage ratio, as defined in the credit agreement, from 5.00 to 1.00 to 5.50 to 1.00 and (vi) included a maximum permitted senior secured leverage ratio, as defined in the credit agreement, of 3.75 to 1.00. In June 2019, we executed the second amendment to the third amended and restated credit agreement that, among other things, made accommodations for the transactions contemplated by the Agreement and designated Double E as an unrestricted subsidiary under the Revolving Credit Facility. In December 2019, we executed the third amendment to the third amended and restated credit agreement that, among other things, designated the Non-Guarantor Borrowings under the Revolving Credit Facility bear interest, at the election of Summit Holdings, at a rate based on the alternate base rate (as defined in the credit agreement) plus an applicable margin ranging from 0.75% to 1.75% or the adjusted Eurodollar rate (as defined in the credit agreement) plus an applicable margin ranging from 1.75% to 2.75%, with the commitment fee ranging from 0.30% to 0.50% in each case based on our relative leverage at the time of determination. At December 31, 2019, the applicable margin under LIBOR borrowings was 2.75%, the interest rate was 4.55% and the unused portion of the Revolving Credit Facility totaled $563.9 million, subject to a commitment fee of 0.50%, after giving effect to the issuance thereunder of a $9.1 million outstanding but undrawn irrevocable standby letter of credit. Based on covenant limits, our available borrowing capacity under the Revolving Credit Facility as of December 31, 2019 was approximately $100 million. See Note 16 for additional information on our letter of credit. The Revolving Credit Facility is secured by the membership interests of Summit Holdings and the membership interests of the Guarantor Subsidiaries of Summit Holdings and by substantially all of the assets of Summit Holdings and its Guarantor Subsidiaries (subject to exclusions set forth in the credit agreement). The credit agreement contains affirmative and negative covenants customary for credit facilities of its size and nature that, among other things, limit or restrict the ability (i) to incur additional debt; (ii) to make investments; (iii) to engage in certain mergers, consolidations, acquisitions or sales of assets; (iv) to enter into swap agreements and power purchase agreements; (v) to enter into leases that would cumulatively obligate payments in excess of $50.0 million over any 12 -month period; and (vi) of Summit Holdings to make distributions, with certain exceptions, including the distribution of Available Cash (as defined in the SMLP Partnership Agreement) if no default or event of default then exists or would result therefrom and Summit Holdings is in pro forma compliance with its financial covenants. In addition, the Revolving Credit Facility requires Summit Holdings to maintain (i) a ratio of consolidated trailing 12 -month earnings before interest, income taxes, depreciation and amortization (“EBITDA”) to net interest expense of not less than 2.5 to 1.0 as defined in the credit agreement, (ii) a ratio of total net indebtedness to consolidated trailing 12 -month EBITDA of not more than 5.50 to 1.00 and, (iii) a ratio of first lien net indebtedness to consolidated trailing 12 -month EBITDA of not more than 3.75 to 1.00. As of December 31, 2019, we had $6.2 million of debt issuance costs attributable to our Revolving Credit Facility and related amendments which are included in Other noncurrent assets on the consolidated balance sheet. As of December 31, 2019, we were in compliance with the Revolving Credit Facility’s financial covenants. There were no defaults or events of default during the year ended December 31, 2019. Senior Notes. “Co-Issuers”) co-issued In 2018, we executed supplemental indentures to include OpCo, Summit Utica, Meadowlark Midstream and Tioga Midstream (through March 22, 2019) as guarantors concurrent with the purchase of a 1% noncontrolling interest held by a subsidiary of Summit Investments (see Note 12 to the consolidated financial statements for additional details). In 2019, we executed a partial release agreement that designated the Non-Guarantor The Guarantor Subsidiaries are 100% owned by a subsidiary of SMLP. The Guarantor Subsidiaries and SMLP fully and unconditionally and jointly and severally guarantee the Senior Notes. There are no significant restrictions on the ability of SMLP or Summit Holdings to obtain funds from its subsidiaries by dividend or loan. Finance Corp. has had no assets or operations since inception in 2013. We have no other independent assets or operations. At no time have the Senior Notes been guaranteed by the Co-Issuers. 5.75% Senior Notes Co-Issuers At any time prior to April 15, 2020, the Co-Issuers Co-Issuers The 5.75% Senior Notes’ indenture restricts SMLP’s and the Co-Issuers’ The 5.75% Senior Notes’ indenture provides that each of the following is an event of default: (i) default for 30 days in the payment when due of interest on the 5.75% Senior Notes; (ii) default in the payment when due of the principal of, or premium, if any, on the 5.75% Senior Notes; (iii) failure by the Co-Issuers Co-Issuers 5.5% Senior Notes At any time prior to August 15, 2020, the Co-Issuers The 5.5% Senior Notes’ indenture restricts SMLP’s and the Co-Issuers’ The 5.5% Senior Notes’ indenture provides that each of the following is an event of default: (i) default for 30 days in the payment when due of interest on the 5.5% Senior Notes; (ii) default in the payment when due of the principal of, or premium, if any, on the 5.5% Senior Notes; (iii) failure by the Co-Issuers comply with certain covenants relating to the filing of reports with the SEC; (v) failure by the Co-Issuers As of and during the December 31, 2019, we were in compliance with the financial covenants governing our Senior Notes. There were no defaults or events of default during the year ended December 31, 2019. SMP Holdings Term Loan. The Term Loan B contains certain customary negative covenants, including but not limited to, limitations on the incurrence of debt, limitations on liens, limitations on asset sales and sale leasebacks, limitations on investments, limitations on dividends, limitations on distributions, limitations on prepayments, and limitations on transactions with affiliates. The Term Loan B also includes a maintenance covenant consisting of a minimum interest coverage ratio whereby the Company is required to maintain a ratio of operating cash flow less general and administrative expenses paid to cash interest expense for the test period (as defined in the Term Loan B credit agreement) of not less than 2.0 to 1.0. The Term Loan B contains certain customary representations and warranties, affirmative covenants and events of default, including but not limited to, payment defaults, breaches of representations and warranties, covenant defaults, certain events of insolvency or bankruptcy, material judgments, certain events under ERISA, actual or asserted failures of any guaranty or security document supporting the Term Loan B to be in full force and effect and changes of control. At December 31, 2019, the Term Loan B is secured by the following collateral): (i) a perfected first-priority lien on, and pledge of (A) all of the capital stock issued by SMP Holdings, (B) 34.6 million SMLP units owned by SMP Holdings (see Note 13), (C) all of the equity interests owned by SMP Holdings in Summit Midstream GP, LLC, which is the general partner of SMLP, and (ii) substantially all other personal property of SMP Holdings. Loans under the Term Loan B must be prepaid under certain circumstances, including with proceeds from certain future debt issuances, asset sales and a portion of excess cash flow for the applicable fiscal quarter. Loans under the Term Loan B may be voluntarily prepaid at any time, subject to certain redemption prices and customary LIBOR breakage costs. SMP Holdings is required to repay principal amounts outstanding under the Term Loan B quarterly, based on a fixed amortization schedule and to prepay its debt obligations based on an excess cash flow calculation for the applicable fiscal quarter which is determined in accordance with the terms of the Term Loan B credit agreement. The Company’s current portion of long-term debt, which includes scheduled principal amortization and excess cash flow prepayments, includes $2.5 million with respect to its fourth quarter 2019 required excess cash flow payment which will be paid within the second quarter of 2020. We have not included an estimated excess cash flow amount in the current portion of long-term debt relating to the first, second and third quarter of 2020 because the amount is not currently estimable given that the excess cash flow calculation is based on the occurrence of future events. As a result of the Term Loan B, the Company incurred approximately $8.7 million of debt issuance costs

FINANCIAL INSTRUMENTS

FINANCIAL INSTRUMENTS	3 Months Ended	12 Months Ended
FINANCIAL INSTRUMENTS	Mar. 31, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
FINANCIAL INSTRUMENTS	10. FINANCIAL INSTRUMENTS Concentrations of Credit Risk. Accounts receivable primarily comprise amounts due for the gathering, compression, treating and processing services we provide to our customers and also the sale of natural gas liquids resulting from our processing services. This industry concentration has the potential to impact our overall exposure to credit risk, either positively or negatively, in that our customers may be similarly affected by changes in economic, industry or other conditions. We monitor the creditworthiness of our counterparties and can require letters of credit or other forms of credit assurance for receivables from counterparties that are judged to have substandard credit, unless the credit risk can otherwise be mitigated. Our top five customers or counterparties accounted for 49% of total accounts receivable as of March 31, 2020, compared with 46% as of December 31, 2019. Fair Value. A summary of the estimated fair value of our debt financial instruments follows. March 31, 2020 December 31, 2019 Carrying value Estimated fair value (Level 2) Carrying value Estimated fair value (Level 2) (In thousands) Summit Holdings 5.5% Senior Notes ($300.0 million principal) $ 298,479 $ 58,875 $ 298,314 $ 266,750 Summit Holdings 5.75% Senior Notes ($500.0 million principal) 495,237 53,125 494,985 382,708 The carrying value on the balance sheet of the Revolving Credit Facility and the Term Loan B is its fair value due to its floating interest rate. The fair value for the Senior Notes is based on an average of nonbinding broker quotes as of March 31, 2020 and December 31, 2019. The use of different market assumptions or valuation methodologies may have a material effect on the estimated fair value of the Senior Notes.	11. FINANCIAL INSTRUMENTS Concentrations of Credit Risk. Accounts receivable primarily comprise amounts due for the gathering, compression, treating and processing services we provide to our customers and also the sale of natural gas liquids resulting from our processing services. This industry concentration has the potential to impact our overall exposure to credit risk, either positively or negatively, in that our customers may be similarly affected by changes in economic, industry or other conditions. We monitor the creditworthiness of our counterparties and can require letters of credit or other forms of credit assurance for receivables from counterparties that are judged to have substandard credit, unless the credit risk can otherwise be mitigated. Our top five customers or counterparties accounted for 46% of total accounts receivable at December 31, 2019, compared to 39% as of December 31, 2018. Fair Value. A summary of the estimated fair value of our debt financial instruments follows. December 31, 2019 December 31, 2018 Carrying value Estimated fair value (Level 2) Carrying value Estimated fair value (Level 2) (In thousands) Summit Holdings 5.5% Senior Notes ($300.0 million principal) $ 298,314 $ 266,750 $ 297,638 $ 286,625 Summit Holdings 5.75% Senior Notes ($500.0 million principal) 494,985 382,708 494,093 455,208 The carrying value on the balance sheet of the Revolving Credit Facility and the Term Loan B is its fair value due to its floating interest rate. The fair value for the Senior Notes is based on an average of nonbinding broker quotes as of December 31, 2019 and 2018. The use of different market assumptions or valuation methodologies may have a material effect on the estimated fair value of the Senior Notes.

PARTNERS' CAPITAL AND MEZZANINE

PARTNERS' CAPITAL AND MEZZANINE CAPITAL	3 Months Ended	12 Months Ended
PARTNERS' CAPITAL AND MEZZANINE CAPITAL	Mar. 31, 2020	Dec. 31, 2019
Equity [Abstract]
PARTNERS' CAPITAL AND MEZZANINE CAPITAL	11. PARTNERS’ CAPITAL AND MEZZANINE CAPITAL As a result of the GP Buy-In Buy-In SMLP General Partner and Incentive Distribution Rights (“IDR”) Exchange. Series A Preferred Units. Subsidiary Series A Preferred Units. During the three months ended March 31, 2020, we issued an additional 35,000 Subsidiary Series A Preferred Units representing limited partner interests in Permian Holdco at a price of $1,000 per unit. We used the net proceeds of $33.9 million (after deducting underwriting discounts and offering expenses) to fund our share of capital expenses associated with the Double E Project. The proceeds associated with the issuance of Subsidiary Series A Preferred Units are classified as restricted cash on the accompanying unaudited condensed consolidated balance sheets in accordance with the underlying agreement with TPG Energy Solutions Anthem, L.P. until the related funding is used for the Double E Project. Cash Distributions Paid and Declared. Prior to the GP Buy-In Transaction, SMLP per-unit during the three months ended March 31 (All payments represent per-unit distributions based on the SMLP common units outstanding prior to the GP Buy-In Transaction): Three months ended March 31, 2020 2019 Per-unit $ 0.125 $ 0.575 With respect to our Subsidiary Series A Preferred Units relating to the first quarter of 2020, we declared a payment-in-kind	12. PARTNERS’ CAPITAL AND MEZZANINE CAPITAL As a result of the GP Buy-In SMLP General Partner and Incentive Distribution Rights (“IDR”) Exchange. DPPO Partial Settlement. Unit Offerings. At-the-market Series A Preferred Units. Fixed-to-Floating The Series A Preferred Units rank senior to (i) common units representing limited partner interests in the Partnership and (ii) each other class or series of limited partner interests or other equity securities in the Partnership that may be established in the future that expressly ranks junior to the Series A Preferred Units as to the payment of distributions and amounts payable upon a liquidation event (the “Junior Securities”). The Series A Preferred Units rank equal in all respects with each class or series of limited partner interests or other equity securities in the Partnership that may be established in the future that is not expressly made senior or subordinated to the Series A Preferred Units as to the payment of distributions and amounts payable on a liquidation event (the “Parity Securities”). The Series A Preferred Units rank junior to (i) all of the Partnership’s existing and future indebtedness and other liabilities with respect to assets available to satisfy claims against the Partnership and (ii) each other class or series of limited partner interests or other equity securities in the Partnership established in the future that is expressly made senior to the Series A Preferred Units as to the payment of distributions and amounts payable upon a liquidation event. Income is allocated to the Series A Preferred Units in an amount equal to the earned distributions for the respective reporting period. Distributions on the Series A Preferred Units are cumulative and compounding and are payable semi-annually in arrears on the 15th day of each June and December through and including December 15, 2022, and, thereafter, quarterly in arrears on the 15th day of March, June, September and December of each year (each, a “Distribution Payment Date”) to holders of record as of the close of business on the first business day of the month of the applicable Distribution Payment Date, in each case, when, as, and if declared by the General Partner out of legally available funds for such purpose. The initial distribution rate for the Series A Preferred Units is 9.50% per annum of the $1,000 liquidation preference per Series A Preferred Unit. On and after December 15, 2022, distributions on the Series A Preferred Units will accumulate for each distribution period at a percentage of the liquidation preference equal to the three-month LIBOR plus a spread of 7.43%. Subsidiary Series A Preferred Units. On January 16, 2020, we issued 10,000 Subsidiary Series A Preferred Units representing limited partner interests in Permian Holdco at a price of $1,000 per unit. We used the net proceeds of $9.7 million (after deducting underwriting discounts and offering expenses) to fund capital expenses associated with the Double E Project. The proceeds associated with the issuance of Subsidiary Series A Preferred Units is classified as restricted cash on the accompanying consolidated balance sheets in accordance with the underlying agreement with TPG Energy Solutions Anthem, L.P. until the related funding is used for the Double E Project. Accounting for the Subsidiary Series A Preferred Units These preferred units are considered redeemable securities under GAAP due to the existence of certain redemption provisions that are outside of our control. Therefore, the securities are classified as temporary equity in the mezzanine section of the consolidated balance sheet. Initial and Subsequent Measurement We initially recognized these preferred units at the time of issuance in the amount of $27.4 million, their issuance date fair value, net of issuance costs. We will not be required to adjust the carrying amount of these preferred units unless it becomes probable that the units would become redeemable. If events or circumstances indicate that redemption is probable, we would accrete these preferred units to the redemption value over a period of time comprising the date redemption first became probable and the date the units can first be redeemed. The Subsidiary Series A Preferred Units rank senior to each other class or series of limited partner interests or other equity securities in Permian Holdco that may be established in the future that expressly ranks junior to the Subsidiary Series A Preferred Units as to the payment of distributions and amounts payable upon a liquidation event (the “Junior Securities”). The Subsidiary Series A Preferred Units rank equal in all respects with each class or series of limited partner interests or other equity securities in Permian Holdco that may be established in the future that is not expressly made senior or subordinated to the Subsidiary Series A Preferred Units as to the payment of distributions and amounts payable on a liquidation event (the “Parity Securities”). The Subsidiary Series A Preferred Units rank junior to (i) all of Permian Holdco’s or a subsidiary of Permian Holdco’s future indebtedness and other liabilities with respect to assets available to satisfy claims against Permian Holdco and (ii) each other class or series of limited partner interests or other equity securities in Permian Holdco established in the future that is expressly made senior to the Subsidiary Series A Preferred Units as to the payment of distributions and amounts payable upon a liquidation event. Income is allocated to the Subsidiary Series A Preferred Units in an amount equal to the earned distributions for the respective reporting period. Distributions on the Subsidiary Series A Preferred Units are cumulative and compounding and are payable 21 days following the quarterly period ended March, June, September and December of each year (each, a “Series A Distribution Payment Date”) to holders of record as of the close of business on the first business day of the month of the applicable Series A Distribution Payment Date, in each case, when, as, and if declared by Permian Holdco out of legally available funds for such purpose. The distribution rate for the Subsidiary Series A Preferred Units is 7.00% per annum of the $1,000 liquidation preference per Subsidiary Series A Preferred Unit. A pro-rated Paid-in-kind Cash Distribution Policy Our Partnership Agreement requires that we distribute all of our available cash, subject to reserves established by our General Partner, within 45 days after the end of each quarter to unitholders of record on the applicable record date. The amount of distributions paid under our policy is subject to fluctuations based on the amount of cash we generate from our business and the decision to make any distribution is determined by our General Partner, taking into consideration the terms of our Partnership Agreement. Cash Distributions Paid and Declared. per-unit Buy-In Year ended December 31, 2019 2018 2017 Per-unit $ 1.4375 $ 2.300 $ 2.300 On January 29, 2020, the Board of Directors declared a distribution of $0.125 per unit for the quarterly period ended December 31, 2019. This distribution, which totaled $11.7 million, was paid on February 14, 2020 to unitholders of record at the close of business on February 7, 2020. With respect to our Subsidiary Series A Preferred Units relating to the fourth quarter of 2019, we declared a payment-in-kind pro-rated pro-rated

EARNINGS PER UNIT

EARNINGS PER UNIT	3 Months Ended	12 Months Ended
EARNINGS PER UNIT	Mar. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
EARNINGS PER UNIT	12. EARNINGS PER UNIT The following table details the components of EPU. Three months ended March 31, 2020 2019 (In thousands, except per-unit amounts) Numerator for basic and diluted EPU: Allocation of net income (loss) among limited partner interests: Net income (loss) attributable to limited partners $ 5,643 $ (14,710 ) Less net income attributable to Series A Preferred Units 7,125 7,125 Less net income attributable to Subsidiary Series A Preferred Units 945 — Net loss attributable to common limited partners $ (2,427 ) $ (21,835 ) Denominator for basic and diluted EPU: Weighted-average common units outstanding – basic and diluted (1) 45,319 45,319 Loss per limited partner unit: Common unit – basic $ (0.05 ) $ (0.48 ) Common unit – diluted $ (0.05 ) $ (0.48 ) Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU 1,889 34 (1) As a result of the GP Buy-In As discussed in Note 9, the Term Loan B is secured by 34.6 million SMLP units owned by SMP Holdings. These common units have not been included in the calculation of EPU because they are not deemed contingently issuable under GAAP.	13. EARNINGS PER UNIT The following table details the components of EPU. Year ended December 31, 2019 2018 2017 (In thousands, except per-unit Numerator for basic and diluted EPU: Allocation of net (loss) income among limited partner interests: Net (loss) income attributable to limited partners $ (184,451 ) $ 31,546 $ (183,411 ) Less net income attributable to Series A Preferred Units 28,500 28,500 3,563 Less net income attributable to Subsidiary Series A Preferred Units 58 — — Net (loss) income attributable to common limited partners $ (213,009 ) $ 3,046 $ (186,974 ) Denominator for basic and diluted EPU: Weighted-average common units outstanding – basic (1) 45,319 45,319 45,319 Effect of nonvested phantom units — 311 — Weighted-average common units outstanding – diluted 45,319 45,630 45,319 (Loss) earnings per limited partner unit: Common unit – basic $ (4.70 ) $ 0.07 $ (4.13 ) Common unit – diluted $ (4.70 ) $ 0.07 $ (4.13 ) Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU 175 2 42 (1) As a result of the GP Buy-In As discussed in Note 10, the Term Loan B is secured by 34.6 million SMLP units owned by SMP Holdings. These common units have not been included in the calculation of EPU because they are not deemed contingently issuable under GAAP.

UNIT-BASED AND NONCASH COMPENSA

UNIT-BASED AND NONCASH COMPENSATION	3 Months Ended	12 Months Ended
UNIT-BASED AND NONCASH COMPENSATION	Mar. 31, 2020	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
UNIT-BASED AND NONCASH COMPENSATION	13. UNIT-BASED AND NONCASH COMPENSATION SMLP Long-Term Incentive Plan. • In March 2020, we granted 3,811,301 phantom units and associated distribution equivalent rights to employees in connection with our annual incentive compensation award cycle. These awards had a grant date fair value of $0.55 and vest ratably over a three-year period. • In March 2020, we also issued 549,450 common units to our three independent directors in connection with their annual compensation plan. • During the three months ended March 31, 2020, 418,999 phantom units vested. • In March 2020, we increased the number of common units authorized under the SMLP LTIP to 15,000,000 common units and extended the term of the SMLP LTIP for 10 years. • As of March 31, 2020, approximately 6.9 million common units remained available for future issuance under the SMLP LTIP.	14. UNIT-BASED AND NONCASH COMPENSATION SMP Net Profits Interests. As of December 31, 2019, 4.2% of SMP Net Profits Interests were vested and outstanding. There were no nonvested SMP Net Profits Interests as of December 31, 2019 and 2018. SMLP Long-Term Incentive Plan. The SMLP LTIP provides for the granting, from time to time, of unit-based awards, including common units, restricted units, phantom units, unit options, unit appreciation rights, distribution equivalent rights, profits interest units and other unit-based awards. Grants are made at the discretion of the Board of Directors or Compensation Committee of our General Partner. The administrator of the SMLP LTIP may make grants under the SMLP LTIP that contain such terms, consistent with the SMLP LTIP, as the administrator may determine are appropriate, including vesting conditions. The administrator of the SMLP LTIP may, in its discretion, base vesting on the grantee’s completion of a period of service or upon the achievement of specified financial objectives or other criteria or upon a change of control (as defined in the SMLP LTIP) or as otherwise described in an award agreement. Termination of employment prior to vesting will result in forfeiture of the awards, except in limited circumstances as described in the plan documents. Units that are canceled or forfeited will be available for delivery pursuant to other awards. The following table presents phantom unit activity: Units Weighted-average Nonvested phantom units, January 1, 2017 691,955 $ 19.59 Phantom units granted 371,972 22.50 Phantom units vested (293,222 ) 24.76 Phantom units forfeited (21,431 ) 20.07 Nonvested phantom units, December 31, 2017 749,274 20.07 Phantom units granted 515,358 15.25 Phantom units vested (359,016 ) 22.39 Phantom units forfeited (41,492 ) 17.27 Nonvested phantom units, December 31, 2018 864,124 17.11 Phantom units granted 1,913,099 6.48 Phantom units vested (602,617 ) 16.78 Phantom units forfeited (68,611 ) 12.87 Nonvested phantom units, December 31, 2019 2,105,995 $ 7.69 A phantom unit is a notional unit that entitles the grantee to receive a common unit upon the vesting of the phantom unit or on a deferred basis upon specified future dates or events or, in the discretion of the administrator, cash equal to the fair market value of a common unit. Distribution equivalent rights for each phantom unit provide for a lump sum cash amount equal to the accrued distributions from the grant date to be paid in cash upon the vesting date. Phantom units granted to date generally vest ratably over a three-year period. Grant date fair value is determined based on the closing price of our common units on the date of grant multiplied by the number of phantom units awarded to the grantee. Forfeitures are recorded as incurred. Holders of all phantom units granted to date are entitled to receive distribution equivalent rights for each phantom unit, providing for a lump sum cash amount equal to the accrued distributions from the grant date of the phantom units to be paid in cash upon the vesting date. Upon vesting, phantom unit awards may be settled, at our discretion, in cash and/or common units, but the current intention is to settle all phantom unit awards with common units. The intrinsic value of phantom units that vested during the years ended December 31, follows. Year ended December 31, 2019 2018 2017 (In thousands) Intrinsic value of vested LTIP awards $ 5,940 $ 5,393 $ 6,657 As of December 31, 2019, the unrecognized unit-based compensation related to the SMLP LTIP was $8.5 million. Incremental unit-based compensation will be recorded over the remaining weighted-average vesting period of approximately 1.6 years. Unit-based compensation recognized in general and administrative expense related to awards under the SMLP LTIP follows. Year ended December 31, 2019 2018 2017 (In thousands) SMLP LTIP unit-based compensation $ 8,171 $ 8,328 $ 7,951

RELATED-PARTY TRANSACTIONS

RELATED-PARTY TRANSACTIONS	3 Months Ended	12 Months Ended
RELATED-PARTY TRANSACTIONS	Mar. 31, 2020	Dec. 31, 2019
Related Party Transactions [Abstract]
RELATED-PARTY TRANSACTIONS	14. RELATED-PARTY TRANSACTIONS See Note 11 for disclosure of related partners’ capital and mezzanine capital issuances.	15. RELATED-PARTY See Note 12 for disclosure of related partners’ capital and mezzanine capital issuances.

LEASES, COMMITMENTS AND CONTING

LEASES, COMMITMENTS AND CONTINGENCIES	3 Months Ended	12 Months Ended
LEASES, COMMITMENTS AND CONTINGENCIES	Mar. 31, 2020	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
LEASES, COMMITMENTS AND CONTINGENCIES	15. LEASES, COMMITMENTS AND CONTINGENCIES Leases. three three Some of our leases are subject to annual escalations according to the Consumer Price Index (“CPI”). While lease liabilities are not remeasured as a result of changes to the CPI, changes to the CPI are treated as variable lease payments and recognized in the period in which the obligation for those payments was incurred. We have options to extend the lease and sublease terms of certain office space in Texas, Colorado and West Virginia. The beginning of the noncancelable lease and sublease period for these agreements ranges from 2014 to 2020 and the lease and sublease period ends between 2020 and 2028. These lease and sublease agreements contain between one and three options to renew the lease and sublease for a period of between two We also have options to extend the lease term of certain compression equipment used at the Summit Utica gathering system. The beginning of the noncancelable lease period for these leases is 2017 and the lease period ends in 2020. In April 2020, we renewed the lease period for periods of one to three years. Our future minimum lease payments are approximately $2.3 million. Our leases do not contain residual value guarantees. In accordance with the provisions in our Revolving Credit Facility, our aggregate finance lease obligations cannot exceed $50 million in any period of twelve consecutive calendar months during the life of such leases. In accordance with the provisions in our Term Loan B, our aggregate finance lease obligations cannot exceed $5 million. In March 2019, we entered into an agreement with a third - up-front twelve-month Our significant assumptions or judgments include the determination of whether a contract contains a lease and the discount rate used in our lease liabilities. The rate implicit in our lease contracts is not readily determinable. In determining the discount rate used in our lease liabilities, we analyzed certain factors in our incremental borrowing rate, including collateral assumptions and the term used. Our incremental borrowing rate on the Revolving Credit Facility was 4.55% at December 31, 2019, which reflects the fixed rate at which we could borrow a similar amount, for a similar term and with similar collateral as in the lease contracts at the commencement date. ROU assets (included in the Property, plant and equipment, net caption on our unaudited condensed consolidated balance sheet) and lease liabilities (included in the Other current liabilities and Other noncurrent liabilities captions on our unaudited condensed consolidated balance sheet) follow: March 31, 2020 December 31, 2019 (In thousands) ROU assets Operating $ 4,306 $ 3,580 Finance 2,649 3,159 $ 6,955 $ 6,739 Lease liabilities, current Operating $ 967 $ 1,221 Finance 1,023 1,246 $ 1,990 $ 2,467 Lease liabilities, noncurrent Operating $ 3,482 $ 2,513 Finance 483 676 $ 3,965 $ 3,189 Lease cost and Other information follow: Three months ended March 31, 2020 2019 (In thousands) Lease cost Finance lease cost: Amortization of ROU assets (included in depreciation and amortization) $ 352 $ 368 Interest on lease liabilities (included in interest expense) 18 23 Operating lease cost (included in general and administrative expense) 772 832 $ 1,142 $ 1,223 Three months ended March 31, 2020 2019 (In thousands) Other information Cash paid for amounts included in the measurement of lease liabilities Operating cash outflows from operating leases $ 708 $ 821 Operating cash outflows from finance leases 18 23 Financing cash outflows from finance leases 417 445 ROU assets obtained in exchange for new operating lease liabilities 1,199 — ROU assets obtained in exchange for new finance lease liabilities — 693 Weighted-average remaining lease term (years) - operating leases 6.0 3.5 Weighted-average remaining lease term (years) - finance leases 2.0 2.0 Weighted-average discount rate - operating leases 5 % 5 % Weighted-average discount rate - finance leases 4 % 4 % We recognize total lease expense incurred or allocated to us in general and administrative expenses. Lease expense related to operating leases, including lease expense incurred on our behalf and allocated to us, was as follows: Three months ended March 31, 2020 2019 (In thousands) Lease expense $ 953 $ 990 Future minimum lease payments due under noncancelable leases for the remainder of 2020 and each of the five succeeding fiscal years and thereafter, were as follows: March 31, 2020 (In thousands) Operating Finance 2020 $ 1,046 $ 873 2021 1,125 606 2022 883 76 2023 741 — 2024 555 — 2025 464 — Thereafter 742 — Total future minimum lease payments $ 5,556 $ 1,555 Future minimum lease payments due under noncancelable leases at December 31, 2019 and each of the five succeeding fiscal years and thereafter, were as follows: December 31, 2019 (In thousands) Operating Finance 2020 $ 1,705 $ 1,299 2021 1,004 616 2022 551 76 2023 408 — 2024 240 — 2025 153 — Thereafter 742 — Total future minimum lease payments $ 4,803 $ 1,991 Environmental Matters. In 2015, we learned of the rupture of a four-inch produced water gathering pipeline on the Meadowlark Midstream system near Williston, North Dakota. The incident, which was covered by insurance policies, was subject to maximum coverage of $25.0 million from its pollution liability insurance policy and $200.0 million from its property and business interruption insurance policy. The pollution liability policy was exhausted in 2015. A rollforward of the aggregate accrued environmental remediation liabilities follows. Total (In thousands) Accrued environmental remediation, January 1, 2020 $ 4,651 Payments made (17 ) Accrued environmental remediation, March 31, 2020 $ 4,634 As of March 31, 2020, we have recognized (i) a current liability for remediation effort expenditures expected to be incurred within the next 12 months and (ii) a noncurrent liability for estimated remediation expenditures and fines expected to be incurred subsequent to March 31, 2021. Each of these amounts represent our best estimate for costs expected to be incurred. Neither of these amounts has been discounted to its present value. While we cannot predict the ultimate outcome of this matter with certainty for the Partnership or Meadowlark Midstream, especially as it relates to any material liability as a result of any governmental proceeding related to the incident, we believe at this time that it is unlikely that the Partnership will be subject to any material liability as a result of any governmental proceeding related to the rupture. Prior to the GP Buy-In Legal Proceedings.	16. LEASES, COMMITMENTS AND CONTINGENCIES Leases. We lease certain office space and equipment under operating leases. We lease office space for our corporate headquarters as well as for corporate offices in Dallas, Denver and Atlanta and offices in and around our gathering systems for terms of between 3 and 10 years. We lease the office space to limit exposure to risks related to ownership, such as fluctuations in real estate prices. In addition, we lease equipment primarily to support our operations in response to the needs of our gathering systems for terms of between 3 and 4 years. We also lease vehicles under finance leases to support our operations in response to the needs of our gathering systems for a term of 3 years. We only lease from reputable companies and our leased assets are not specialized in our industry. Some of our leases are subject to annual escalations relating to the Consumer Price Index (“CPI”). While lease liabilities are not remeasured as a result of changes to the CPI, changes to the CPI are treated as variable lease payments and recognized in the period in which the obligation for those payments was incurred. We have options to extend the lease term of certain office space in Texas, Colorado and West Virginia. The beginning of the noncancelable lease period for these leases ranged from 2014 to 2018 and the lease period ends between 2020 and 2028. These lease agreements contain between one and three options to renew the lease for a period of between two We also have options to extend the lease term of certain compression equipment used at the Summit Utica gathering system. The beginning of the noncancelable lease period for these leases was 2017 and the lease period ends in 2020. Upon expiration of the noncancelable lease period, we have the option to renew the leases on a month-to-month basis; we therefore have not included any amounts attributable to renewals in the measurement. Our leases do not contain residual value guarantees. In accordance with the provisions in our Revolving Credit Facility, our aggregate finance lease obligations cannot exceed $50 million in any period of twelve consecutive calendar months during the life of such leases. In accordance with the provisions in our Term Loan B, our aggregate finance lease obligations cannot exceed $5 million. In November 2019, we entered into a sublease agreement with a third party to sublease corporate office space in Houston, Texas. The noncancelable sublease period begins in 2020 and the sublease period ends in 2025. The sublease agreement contains one option to renew the lease for five years. We moved our corporate headquarters to the Houston office on March 2, 2020. Our future minimum sublease payments are approximately $1.2 million. In March 2019, we entered into an agreement with a third party vendor to construct a transmission line to deliver electric power to the new 60 MMcf/d processing plant in the DJ Basin. The project is expected to cost approximately $7.8 million and we made an up-front twelve month Our significant assumptions or judgments include the determination of whether a contract contains a lease and the discount rate used in our lease liabilities. The rate implicit in our lease contracts is not readily determinable. In determining the discount rate used in our lease liabilities, we analyzed certain factors in our incremental borrowing rate, including collateral assumptions and the term used. Our incremental borrowing rate on the Revolving Credit Facility was 4.55% at December 31, 2019, which reflects the fixed rate at which we could borrow a similar amount, for a similar term and with similar collateral as in the lease contracts at the commencement date. We adopted the following practical expedients in Topic 842 for all asset classes, which included (i) not being required to reassess whether any expired or existing contracts are or contain leases; (ii) not being required to reassess the lease classification for any expired or existing leases (that is, all existing leases that were classified as operating leases in accordance with Topic 840 will be classified as operating leases, and all existing leases that were classified as capital leases in accordance with Topic 840 will be classified as finance leases); (iii) not being required to reassess initial direct costs for any existing leases; (iv) not recognizing ROU assets and lease liabilities that arise from short-term leases of twelve months or less for any class of underlying asset; (v) not allocating consideration in a contract between lease and nonlease (e.g., maintenance services) components for our leased office space and equipment; and (vi) not evaluating existing or expired land easements that were not previously accounted for as leases under Topic 840. ROU assets (included in the Property, plant and equipment, net caption on our consolidated balance sheet) and lease liabilities (included in the Other current liabilities and Other noncurrent liabilities captions on our consolidated balance sheet) follow: December 31, 2019 (In thousands) ROU assets Operating $ 3,580 Finance 3,159 $ 6,739 Lease liabilities, current Operating $ 1,221 Finance 1,246 $ 2,467 Lease liabilities, noncurrent Operating $ 2,513 Finance 676 $ 3,189 Lease cost and Other information follow: Year ended December 31, 2019 (In thousands) Lease cost Finance lease cost: Amortization of ROU assets (included in depreciation and amortization) $ 1,559 Interest on lease liabilities (included in interest expense) 102 Operating lease cost (included in general and administrative expense) 3,345 $ 5,006 Twelve months ended December 31, 2019 (In thousands) Other information Cash paid for amounts included in the measurement of lease liabilities Operating cash outflows from operating leases $ 3,396 Operating cash outflows from finance leases 102 Financing cash outflows from finance leases 1,873 ROU assets obtained in exchange for new operating lease liabilities 1,218 ROU assets obtained in exchange for new finance lease liabilities 1,350 Weighted-average remaining lease term (years) - operating leases 5.8 Weighted-average remaining lease term (years) - finance leases 2.0 Weighted-average discount rate - operating leases 5 % Weighted-average discount rate - finance leases 4 % We recognize total lease expense incurred or allocated to us in general and administrative expenses. Lease expense related to operating leases, including lease expense incurred on our behalf and allocated to us, was as follows: Year ended December 31, 2019 2018 2017 (In thousands) Lease expense $ 4,038 $ 4,108 $ 3,963 Future minimum lease payments due under noncancelable leases at December 31, 2019, were as follows December 31, 2019 (In thousands) Operating Finance 2020 $ 1,705 $ 1,299 2021 1,004 616 2022 551 76 2023 408 — 2024 240 — 2025 153 — Thereafter 742 — Total future minimum lease payments $ 4,803 $ 1,991 Future minimum lease payments due under noncancelable operating leases (under ASC 840) at December 31, 2018, were as follows: December 31, 2018 (In thousands) 2019 $ 3,133 2020 1,018 2021 550 2022 506 2023 373 Thereafter 621 Total future minimum lease payments $ 6,201 Future payments due under finance leases (under ASC 840) at December 31, 2018, were as follows: December 31, 2018 (In thousands) 2019 $ 1,473 2020 902 2021 174 Total finance lease obligations 2,549 Less: Amounts representing interest (104 ) Net present value of finance lease obligations 2,445 Less: Amount representing current portion (included in Other current liabilities) (1,406 ) Finance lease obligations, less current portion (included in Other noncurrent liabilities) $ 1,039 Environmental Matters. In 2015, we learned of the rupture of a four-inch produced water gathering pipeline on the Meadowlark Midstream system near Williston, North Dakota. The incident, which was covered by our insurance policies, was subject to maximum coverage of $25.0 million from its pollution liability insurance policy and $200.0 million from its property and business interruption insurance policy. We exhausted the $25.0 million pollution liability policy in 2015. We submitted property and business interruption claim requests to the insurers and reached a settlement in January 2017. In connection therewith, we recognized $2.6 million of business interruption recoveries and $0.4 million of property recoveries. A rollforward of the aggregate accrued environmental remediation liabilities follows. Total (In thousands) Accrued environmental remediation, January 1, 2018 $ 5,344 Payments made (3,808 ) Additional accruals 4,100 Accrued environmental remediation, December 31, 2018 $ 5,636 Payments made (2,284 ) Additional accruals 1,299 Accrued environmental remediation, December 31, 2019 $ 4,651 As of December 31, 2019, we have recognized (i) a current liability for remediation effort expenditures expected to be incurred within the next 12 months and (ii) a noncurrent liability for estimated remediation expenditures and fines expected to be incurred subsequent to December 31, 2020. Each of these amounts represent our best estimate for costs expected to be incurred. Neither of these amounts has been discounted to its present value. While we cannot predict the ultimate outcome of this matter with certainty for the Partnership or Meadowlark Midstream, especially as it relates to any material liability as a result of any governmental proceeding related to the incident, we believe at this time that it is unlikely that the Partnership will be subject to any material liability as a result of any governmental proceeding related to the rupture. Prior to the GP Buy-In Legal Proceedings.

DISPOSITIONS, DROP DOWN TRANSAC

DISPOSITIONS, DROP DOWN TRANSACTIONS AND RESTRUCTURING	3 Months Ended	12 Months Ended
DISPOSITIONS, DROP DOWN TRANSACTIONS AND RESTRUCTURING	Mar. 31, 2020	Dec. 31, 2019
Business Combinations [Abstract]
DISPOSITIONS, DROP DOWN TRANSACTIONS AND RESTRUCTURING	16. DISPOSITIONS, DROP DOWN TRANSACTIONS AND RESTRUCTURING Tioga Midstream Disposition. Restructuring Activities. As of March 31, 2020, the components of our restructuring plan are as follows: • Employee-related costs — We reorganized our workforce and eliminated redundant or unneeded positions. In connection with the workforce restructuring, we expect to incur severance, benefits and other employee related costs of approximately $4.1 million over the next nine months following March 31, 2020. During the three months ended March 31, 2020, we expensed approximately $1.9 million primarily related to severance, redundant salaries, certain bonuses and other employee benefits in connection with our plan. As of March 31, 2020, cash payments were made of approximately $2.1 million and we had approximately $2.4 million included in the Other current liabilities caption on the unaudited condensed consolidated balance sheets for these costs, which we expect to pay over the remainder of the year. • Consultants — We engaged third-party consulting firms to assist in the evaluation of the Partnership’s cost structure, to help formulate the plan to implement the project, and to provide project management services for certain project initiatives. During the three months ended March 31, 2020, we expensed approximately $0.9 million related to these services. As of March 31, 2020, cash payments of approximately $1.1 million were made and we had approximately $0.4 million included in the Other current liabilities caption on the unaudited condensed consolidated balance sheets for these costs, which we expect to pay over the remainder of the year. We expect to incur an additional $0.2 million related to consulting costs to be incurred over the next nine months following March 31, 2020.	17. DISPOSITIONS, DROP DOWN TRANSACTIONS AND RESTRUCTURING Red Rock Gathering Asset Disposition. Tioga Midstream Disposition. Restructuring Activities. As of December 31, 2019, the components of our restructuring plan are as follows: • Employee-related costs — we reorganized our workforce and eliminated redundant or unneeded positions. In connection with the workforce restructuring, we expect to incur severance, benefits and other employee related costs of approximately $6.0 million to be incurred over the twelve months following December 31, 2019. During the fiscal year ended December 31, 2019, we expensed approximately $3.8 million primarily related to severance, redundant salaries, certain bonuses and other employee benefits in connection with our plan. As of December 31, 2019, we had approximately $2.7 million included in current liabilities for these costs. • Consultants — we engaged third-party consulting firms to assist in the evaluation of the Company’s cost structure, to help formulate the plan to implement the project, and to provide project management services for certain project initiatives. During the fiscal year ended December 31, 2019, we expensed approximately $1.2 million related to these services. As of December 31, 2019, we had approximately $0.6 million included in current liabilities for these costs. We expect to incur an additional $0.2 million related to consulting costs to be incurred over the next twelve months following December 31, 2019.

UNAUDITED QUARTERLY FINANCIAL D

UNAUDITED QUARTERLY FINANCIAL DATA	12 Months Ended
UNAUDITED QUARTERLY FINANCIAL DATA	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
UNAUDITED QUARTERLY FINANCIAL DATA	18. UNAUDITED QUARTERLY FINANCIAL DATA Summarized information on the consolidated results of operations for each of the quarters during the two-year Quarter ended December 31, 2019 September 30, 2019 June 30, 2019 March 31, 2019 (In thousands, except per-unit Total revenues $ 112,247 $ 100,187 $ 99,686 $ 131,408 Net (loss) income attributable to SMLP $ (345,345 ) $ (11,129 ) $ 3,028 $ (40,280 ) Less net loss attributable to noncontrolling interest (172,024 ) (10,340 ) (1,341 ) (25,570 ) Less net income attributable to Series A Preferred Units 7,125 7,125 7,125 7,125 Less net income attributable to Subsidiary Series A Preferred Units 58 — — — Net loss attributable to common limited partners $ (180,504 ) $ (7,914 ) $ (2,756 ) $ (21,835 ) Loss per limited partner unit: Common unit - basic $ (3.98 ) $ (0.17 ) $ (0.06 ) $ (0.48 ) Common unit - diluted $ (3.98 ) $ (0.17 ) $ (0.06 ) $ (0.48 ) Quarter ended December 31, 2018 September 30, 2018 June 30, 2018 March 31, 2018 (In thousands, except per-unit Total revenues $ 133,671 $ 127,479 $ 128,183 $ 117,320 Net (loss) income attributable to SMLP $ (3,401 ) $ 14,353 $ 11,861 $ 11,507 Less net income (loss) attributable to noncontrolling interest 18,535 30,453 (37,712 ) (8,502 ) Less net income attributable to Series A Preferred Units 7,125 7,125 7,125 7,125 Net (loss) income attributable to common limited partners $ (29,061 ) $ (23,225 ) $ 42,448 $ 12,884 (Loss) earnings per limited partner unit: Common unit - basic $ (0.64 ) $ (0.51 ) $ 0.94 $ 0.28 Common unit - diluted $ (0.64 ) $ (0.51 ) $ 0.93 $ 0.28

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	3 Months Ended	12 Months Ended
SUBSEQUENT EVENTS	Mar. 31, 2020	Dec. 31, 2019
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	17. SUBSEQUENT EVENTS We have evaluated subsequent events for recognition or disclosure in the unaudited condensed consolidated financial statements and no events have occurred that require recognition or disclosure, except for the following. On May 28, 2020, the Partnership closed on the Purchase Agreement and acquired (i) all the outstanding limited liability company interests of Summit Investments, which is the sole member of SMP Holdings, which in turn owns (a) 34,604,581 common units representing limited partner interests in the Partnership (the “Common Units”) pledged as collateral under the Term Loan B, (b) 10,714,285 Common Units not pledged as collateral under the Term Loan B and (c) the right of SMP Holdings to receive the deferred purchase price obligation under the Contribution Agreement by and between the Partnership and SMP Holdings, dated February 25, 2016, as amended, and (ii) 5,915,827 Common Units held by SMLP Holdings, LLC, a Delaware limited liability company and an affiliate of ECP. The total purchase price under the Purchase Agreement was $35 million in cash and warrants to purchase up to 10 million Common Units. Pursuant to the Purchase Agreement, SMP Holdings will continue to retain the liabilities stemming from the release of produced water, from a produced water pipeline operated by Meadowlark Midstream Company, LLC that occurred near Marmon, North Dakota and was reported on January 6, 2015. We refer to the transactions contemplated by the Purchase Agreement as the “GP Buy-In At the closing of the GP Buy-In Upon closing of the GP Buy-In On April 10, 2020, we received a formal notice from the New York Stock Exchange (“NYSE”) indicating noncompliance with the continued listing standard set forth in Rule 802.01C of the NYSE Listed Company Manual because the average closing price of our common units had fallen below $1.00 per unit over a period of 30 consecutive trading days, which is the minimum average unit price for continued listing on the NYSE. We have six months following the receipt of the formal noncompliance notice to cure the deficiency and regain compliance. During this period, our common units will continue trading on the NYSE under our existing ticker symbol, with the addition of a suffix indicating the “below criteria” status of our common units, as “SMLP.BC.” We intend to regain compliance with the NYSE listing standards by pursuing measures which include (i) enhanced capital discipline and operating margins, including a planned 30% reduction in 2020 capital expenditures and ongoing implementation of expense savings initiatives; (ii) debt reduction through capital markets transactions and asset sales; and potentially (iii) consummation of a reverse unit split, subject to approval from our board of directors.	19. SUBSEQUENT EVENTS We have evaluated subsequent events for recognition or disclosure in the consolidated financial statements and no events have occurred that require adjustment to or disclosure in the consolidated financial statements, except for the following. On May 28, 2020, the Partnership closed on the Purchase Agreement and acquired (i) all the outstanding limited liability company interests of Summit Investments, which is the sole member of SMP Holdings, which in turn owns (a) 34,604,581 common units representing limited partner interests in the Partnership (the “Common Units”) pledged as collateral under the Term Loan B, (b) 10,714,285 Common Units not pledged as collateral under the Term Loan B and (c) the right of SMP Holdings to receive the deferred purchase price obligation under the Contribution Agreement by and between the Partnership and SMP Holdings, dated February 25, 2016, as amended, and (ii) 5,915,827 Common Units held by SMLP Holdings, LLC, a Delaware limited liability company and an affiliate of ECP. The total purchase price under the Purchase Agreement was $35 million in cash and warrants to purchase up to 10 million Common Units. Pursuant to the Purchase Agreement, SMP Holdings will continue to retain the liabilities stemming from the release of produced water, from a produced water pipeline operated by Meadowlark Midstream Company, LLC that occurred near Marmon, North Dakota and was reported on January 6, 2015. We refer to the transactions contemplated by the Purchase Agreement as the “GP Buy-In Transaction.” At the closing of the GP Buy-In Transaction, Summit Holdings, a Delaware limited liability company and wholly owned subsidiary of the Partnership (the “Borrower”), borrowed an aggregate principal amount of $35 million from certain affiliates of ECP pursuant to two separate term loan agreements that will mature on March 31, 2021 (“Term Loan Credit Agreements”), and upon the terms and subject to the other conditions set forth therein (the “Loans”). The Loans under the Term Loan Credit Agreements will bear interest at a rate of 8.00% per annum, and will generally be (i) guaranteed by the Partnership and each subsidiary of the Borrower that guarantees the obligations under the Borrower’s Revolving Credit Facility, and (ii) secured by a first priority lien on and security interest in all property that secures the obligations under the Revolving Credit Facility. Upon closing of the GP Buy-In Transaction, all directors affiliated with ECP resigned from the Board of Directors. The Board of Directors now consists of a majority of independent directors. Additionally, the Third Amended and Restated Agreement of Limited Partnership of the Partnership was amended and restated, and the Amended and Restated Limited Liability Company Agreement of Partnership’s general partner was amended and restated, to, among other things, provide the holders of common units with voting rights in the election of directors of the Board of Directors on a staggered basis beginning in 2022.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	Mar. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Cash, Cash Equivalents and Restricted Cash		Cash, Cash Equivalents and Restricted Cash.
Accounts Receivable		Accounts Receivable.
Property, Plant and Equipment		Property, Plant and Equipment. We record depreciation on a straight-line basis over an asset’s estimated useful life. We base our estimates for useful life on various factors including age (in the case of acquired assets), manufacturing specifications, technological advances and historical data concerning useful lives of similar assets. Estimates of useful lives follow. Useful lives (In years) Gathering and processing systems and related equipment 12-30 Other 4-15 Construction in progress is depreciated consistent with its applicable asset class once it is placed in service. Land and line fill are not depreciated. We base an asset’s carrying value on estimates, assumptions and judgments for useful life and salvage value. Upon sale, retirement or other disposal, we remove the carrying value of an asset and its accumulated depreciation from our balance sheet and recognize the related gain or loss, if any. Accrued capital expenditures are reflected in trade accounts payable.
Asset Retirement Obligations		Asset Retirement Obligations.
Amortizing Intangibles		Amortizing Intangibles. We amortize all other gas gathering contracts, or contract intangibles, over the period of economic benefit based upon expected revenues over the life of the contract. The useful life of these contracts ranges from 3 years to 25 years. We recognize the amortization expense associated with these contracts in Depreciation and amortization expense. We have rights-of-way rights-of-way. rights-of-way rights-of-way rights-of-way
Goodwill		Goodwill.
Equity Method Investments		Equity Method Investments. one-month We recognize an other-than-temporary impairment for losses in the value of equity method investees when evidence indicates that the carrying amount is no longer supportable. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the equity method investee to sustain an earnings capacity that would justify the carrying amount of the investment. A current fair value of an investment that is less than its carrying amount may indicate a loss in value of the investment. We evaluate our equity method investments whenever a triggering event exists that would indicate a need to assess the investment for potential impairment.
Other Noncurrent Assets		Other Noncurrent Assets.
Debt Issuance Costs		Debt Issuance Costs.
Impairment of Long-Lived Assets		Impairment of Long-Lived Assets.
Derivative Contracts		Derivative Contracts. Accounting standards related to derivative instruments and hedging activities allow for normal purchase or sale elections and hedge accounting designations, which generally eliminate or defer the requirement for mark-to-market
Restructuring Cost		Restructuring Costs.
Fair Value of Financial Instruments		Fair Value of Financial Instruments. • Level 1. Inputs represent quoted prices in active markets for identical assets or liabilities; • Level 2. Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly (for example, quoted market prices for similar assets or liabilities in active markets or quoted market prices for identical assets or liabilities in markets not considered to be active, inputs other than quoted prices that are observable for the asset or liability, or market-corroborated inputs); and • Level 3. Inputs that are not observable from objective sources, such as management’s internally developed assumptions used in pricing an asset or liability (for example, an internally developed present value of future cash flows model that underlies management’s fair value measurement).
Commitments and Contingencies		Commitments and Contingencies.
Revenue Recognition		Revenue Recognition. fee-based We recognize revenue earned from fee-based percent-of-proceeds We provide gathering and/or processing services principally under contracts that contain one or more of the following arrangements: • Fee-based fee-based • Percent-of-proceeds percent-of-proceeds Certain of our gathering and/or processing agreements provide for monthly or annual MVCs. Under these MVCs, our customers agree to ship and/or process a minimum volume of production on our gathering systems or to pay a minimum monetary amount over certain periods during the term of the MVC. A customer must make a shortfall payment to us at the end of the contracted measurement period if its actual throughput volumes are less than its contractual MVC for that period. Certain customers are entitled to utilize shortfall payments to offset gathering fees in one or more subsequent contracted measurement periods to the extent that such customer’s throughput volumes in a subsequent contracted measurement period exceed its MVC for that contracted measurement period. We recognize customer obligations under their MVCs as revenue and contract assets when (i) we consider it remote that the customer will utilize shortfall payments to offset gathering or processing fees in excess of its MVCs in subsequent periods; (ii) the customer incurs a shortfall in a contract with no banking mechanism or claw back provision; (iii) the customer’s banking mechanism has expired; or (iv) it is remote that the customer will use its unexercised right. In making this determination, we consider both quantitative and qualitative facts and circumstances, including, but not limited to, contract terms, capacity of the associated pipeline or receipt point and/or expectations regarding future investment, drilling and production.
Unit-Based Compensation		Unit-Based Compensation.
Income Taxes		Income Taxes. In general, legal entities that are chartered, organized or conducting business in the state of Texas are subject to a franchise tax (the “Texas Margin Tax”). The Texas Margin Tax has the characteristics of an income tax because it is determined by applying a tax rate to a tax base that considers both revenues and expenses. Our financial statements reflect provisions for these tax obligations.
Earnings or Loss Per Unit		Earnings or Loss Per Unit. two-class
Environmental Matters		Environmental Matters.
Recent Accounting Pronouncements	Recently Adopted Accounting Pronouncements • ASU No. 2018-13 2018-13”). 2018-13 2018-13 2018-13 2018-13 • ASU No. 2016-13 2016-13”). 2016-13 off-balance 2016-13 Accounting Pronouncements Pending Adoption • ASU No. 2020-04 2020-04”). 2020-04 2020-04 2020-04	Recent Accounting Pronouncements. Recently Adopted Accounting Pronouncements • ASU No. 2016-02 right-of-use Accounting Pronouncements Pending Adoption • ASU No. 2018-13 2018-13”). 2018-13 2018-13 2018-13 2018-13 • ASU No. 2016-13 2016-13”). 2016-13 off-balance 2016-13
Basis of Presentation	Presentation and Consolidation. These unaudited condensed consolidated financial statements have been prepared pursuant to the rules and the regulations of the SEC. Certain information and note disclosures normally included in the annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules and regulations. We believe that the disclosures made are adequate to make the information not misleading. In the opinion of management, the unaudited condensed consolidated financial statements contain all adjustments which are necessary to fairly present the unaudited condensed consolidated balance sheet as of March 31, 2020, the unaudited condensed consolidated statements of operations and statements of partners’ capital for the three months ended March 31, 2020 and 2019 and the unaudited condensed consolidated statements of cash flows for the three months ended March 31, 2020 and 2019. The balance sheet at December 31, 2019 included herein was derived from our audited financial statements, but does not include all disclosures required by GAAP. These unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto that are included in our annual report on Form 10-K 8-K. Risks and Uncertainties. COVID-19 COVID-19 COVID-19 COVID-19 The full extent to which our operations may be impacted by the COVID-19

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	Dec. 31, 2019
Accounting Policies [Abstract]
Useful lives of Property, Plant and Equipment	Estimates of useful lives follow. Useful lives (In years) Gathering and processing systems and related equipment 12-30 Other 4-15

REVENUE (Tables)

REVENUE (Tables)	3 Months Ended	12 Months Ended
REVENUE (Tables)	Mar. 31, 2020	Dec. 31, 2019
Revenue From Contract With Customer [Abstract]
Schedule of Estimated Revenue Expected to be Recognized and MVC Shortfall Payments	The following table presents estimated revenue expected to be recognized during the remainder of 2020 and over the remaining contract period related to performance obligations that are unsatisfied and are comprised of estimated MVC shortfall payments. We applied the practical expedient in paragraph 606-10-50-14 2020 2021 2022 2023 2024 Thereafter (In thousands) Gathering services and related fees $ 86,916 $ 102,127 $ 84,736 $ 66,693 $ 50,608 $ 58,672	The following table presents estimated revenue expected to be recognized over the remaining contract period related to performance obligations that are unsatisfied and are comprised of estimated MVC shortfall payments. We applied the practical expedient in paragraph 606-10-50-14 2020 2021 2022 2023 2024 Thereafter (In thousands) Gathering services and related fees $ 122,055 $ 102,127 $ 84,736 $ 66,693 $ 50,608 $ 59,602
Schedule of Disaggregated Revenue by Geographic Area and Major Products and Services Reportable Segments	Revenue by Category. Reportable Segments Three months ended March 31, 2020 Utica Williston DJ Permian Piceance Barnett Marcellus Total All other Total (In thousands) Major products / services lines Gathering services and related fees $ 6,962 $ 23,797 $ 6,855 $ 2,311 $ 27,189 $ 10,443 $ 6,235 $ 83,792 $ — $ 83,792 Natural gas, NGLs and condensate sales — 4,324 70 4,512 1,003 3,871 — 13,780 — 13,780 Other revenues — 3,142 1,034 187 1,065 1,260 — 6,688 643 7,331 Total $ 6,962 $ 31,263 $ 7,959 $ 7,010 $ 29,257 $ 15,574 $ 6,235 $ 104,260 $ 643 $ 104,903 Reportable Segments Three months ended March 31, 2019 Utica Williston DJ Permian Piceance Barnett Marcellus Total All other Total (In thousands) Major products / services lines Gathering services and related fees $ 7,495 $ 25,706 $ 3,724 $ 366 $ 31,840 $ 13,025 $ 6,197 $ 88,353 $ (1,389 ) $ 86,964 Natural gas, NGLs and condensate sales — 5,585 85 4,221 2,302 604 — 12,797 25,131 37,928 Other revenues — 2,908 1,007 32 1,138 1,656 — 6,741 (225 ) 6,516 Total $ 7,495 $ 34,199 $ 4,816 $ 4,619 $ 35,280 $ 15,285 $ 6,197 $ 107,891 $ 23,517 $ 131,408	Revenue by Category Reportable Segments Year ended December 31, 2019 Utica Williston DJ Basin Permian Piceance Barnett Marcellus Total All other Total (In thousands) Major products / services lines Gathering services and related fees $ 31,926 $ 77,626 $ 21,940 $ 3,610 $ 121,357 $ 47,862 $ 24,471 $ 328,792 $ (2,045 ) $ 326,747 Natural gas, NGLs and condensate sales — 16,461 389 16,383 7,954 17,147 — 58,334 28,660 86,994 Other revenues 2,065 11,564 3,721 310 4,327 6,793 — 28,780 1,007 29,787 Total $ 33,991 $ 105,651 $ 26,050 $ 20,303 $ 133,638 $ 71,802 $ 24,471 $ 415,906 $ 27,622 $ 443,528 Reportable Segments Year ended December 31, 2018 Utica Williston DJ Basin Permian Piceance Barnett Marcellus Total All other Total (In thousands) Major products / services lines Gathering services and related fees $ 35,233 $ 79,606 $ 11,251 $ 115 $ 135,810 $ 59,030 $ 29,573 $ 350,618 $ (6,002 ) $ 344,616 Natural gas, NGLs and condensate sales — 31,840 371 843 14,800 2,523 — 50,377 84,457 134,834 Other revenues — 12,204 3,672 — 4,909 6,712 — 27,497 (294 ) 27,203 Total $ 35,233 $ 123,650 $ 15,294 $ 958 $ 155,519 $ 68,265 $ 29,573 $ 428,492 $ 78,161 $ 506,653
Schedule of Contract with Customer Asset	The following table provides information about contract assets from contracts with customers: March 31, 2020 December 31, 2019 (In thousands) Contract assets, beginning of period $ 3,902 $ 8,755 Additions 13,877 18,077 Transfers out (425 ) (22,930 ) Contract assets, end of period $ 17,354 $ 3,902	The following table provides information about contract assets from contracts with customers: December 31, 2019 December 31, 2018 (In thousands) Contract assets, beginning of period $ 8,755 $ — Additions 18,077 26,403 Transfers out (22,930 ) (17,648 ) Contract assets, end of period $ 3,902 $ 8,755

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	3 Months Ended	12 Months Ended
SEGMENT INFORMATION (Tables)	Mar. 31, 2020	Dec. 31, 2019
Segment Reporting [Abstract]
Schedule of assets by reportable segment	Assets by reportable segment follow. March 31, 2020 December 31, 2019 (In thousands) Assets (1): Utica Shale $ 205,341 $ 206,368 Ohio Gathering 271,268 275,000 Williston Basin 452,684 452,152 DJ Basin 200,473 205,308 Permian Basin 184,043 185,708 Piceance Basin 622,403 631,140 Barnett Shale 345,248 350,638 Marcellus Shale 184,279 184,631 Total reportable segment assets 2,465,739 2,490,945 Corporate and Other 160,558 83,153 Total assets $ 2,626,297 $ 2,574,098 (1) At March 31, 2020, Corporate and Other included $92.3 million relating to our investment in Double E (included in the Investment in equity method investees caption of the unaudited condensed consolidated balance sheet). At December 31, 2019, Corporate and Other included $34.7 million relating to our investment in Double E.	Assets by reportable segment follow. December 31, 2019 2018 2017 (In thousands) Assets (1): Utica Shale $ 206,368 $ 207,357 $ 212,311 Ohio Gathering 275,000 649,250 690,485 Williston Basin 452,152 526,819 512,860 DJ Basin 205,308 166,580 79,438 Permian Basin 185,708 145,702 57,590 Piceance Basin 631,140 699,638 719,284 Barnett Shale 350,638 376,564 383,306 Marcellus Shale 184,631 208,790 217,362 Total reportable segment assets 2,490,945 2,980,700 2,872,636 Corporate and Other 83,153 56,838 35,332 Eliminations — (4,319 ) (249 ) Total assets $ 2,574,098 $ 3,033,219 $ 2,907,719 (1) At December 31, 2019, Corporate and Other included $34.7 million relating to our investment in Double E (included in the Investment in equity method investees caption of the consolidated balance sheet). At December 31, 2018, Corporate and Other included $9.6 million of capital expenditures relating to the Double E Project.
Schedule of segment reporting information	Revenues by reportable segment follow. Three months ended March 31, 2020 2019 (In thousands) Revenues (1): Utica Shale $ 6,962 $ 7,495 Williston Basin 31,263 34,199 DJ Basin 7,959 4,816 Permian Basin 7,010 4,619 Piceance Basin 29,257 35,280 Barnett Shale 15,574 15,285 Marcellus Shale 6,235 6,197 Total reportable segments revenue 104,260 107,891 Corporate and Other 643 26,838 Eliminations — (3,321 ) Total revenues $ 104,903 $ 131,408 (1) Excludes revenues earned by Ohio Gathering due to equity method accounting. Depreciation and amortization, including the amortization expense associated with our favorable gas gathering contracts as reported in Other revenues, by reportable segment follows. Three months ended March 31, 2020 2019 (In thousands) Depreciation and amortization (1): Utica Shale $ 1,927 $ 1,908 Williston Basin 6,495 5,436 DJ Basin 1,527 799 Permian Basin 1,345 1,072 Piceance Basin 11,298 11,791 Barnett Shale (2) 4,032 4,330 Marcellus Shale 2,300 2,283 Total reportable segment depreciation and amortization 28,924 27,619 Corporate and Other 976 534 Total depreciation and amortization $ 29,900 $ 28,153 (1) Excludes depreciation and amortization recognized by Ohio Gathering due to equity method accounting. (2) Includes the amortization expense associated with our favorable gas gathering contracts as reported in Other revenues. Cash paid for capital expenditures by reportable segment follow. Three months ended March 31, 2020 2019 (In thousands) Cash paid for capital expenditures (1): Utica Shale $ 909 $ 101 Williston Basin 4,943 8,023 DJ Basin 6,298 28,356 Permian Basin 3,281 7,057 Piceance Basin 346 1,226 Barnett Shale (2) 657 (118 ) Marcellus Shale 422 102 Total reportable segment capital expenditures 16,856 44,747 Corporate and Other 1,727 16,101 Total cash paid for capital expenditures $ 18,583 $ 60,848 (1) Excludes cash paid for capital expenditures by Ohio Gathering due to equity method accounting. (2) For the three months ended March 31, 2019, the amount includes sales tax reimbursements of $1.1 million.	Revenues by reportable segment follow. Year ended December 31, 2019 2018 2017 (In thousands) Revenues (1): Utica Shale $ 33,991 $ 35,233 $ 38,907 Williston Basin 105,651 123,650 161,503 DJ Basin 26,050 15,294 11,860 Permian Basin 20,303 958 — Piceance Basin 133,638 155,519 154,893 Barnett Shale 71,802 68,265 71,667 Marcellus Shale 24,471 29,573 30,394 Total reportable segments revenue 415,906 428,492 469,224 Corporate and Other 30,552 88,286 26,446 Eliminations (2,930 ) (10,125 ) (6,929 ) Total revenues $ 443,528 $ 506,653 $ 488,741 (1) Excludes revenues earned by Ohio Gathering due to equity method accounting. Depreciation and amortization, including the amortization expense associated with our favorable and unfavorable (for 2018) gas gathering contracts as reported in other revenues, by reportable segment follows. Year ended December 31, 2019 2018 2017 (In thousands) Depreciation and amortization (1): Utica Shale $ 7,659 $ 7,672 $ 7,009 Williston Basin 19,829 22,642 33,772 DJ Basin 3,732 3,133 2,636 Permian Basin 4,868 243 — Piceance Basin 47,018 46,919 46,289 Barnett Shale (2) 16,575 15,325 15,001 Marcellus Shale 9,141 9,090 9,047 Total reportable segment depreciation and amortization 108,822 105,024 113,754 Corporate and Other 2,752 1,906 1,364 Total depreciation and amortization $ 111,574 $ 106,930 $ 115,118 (1) Excludes depreciation and amortization recognized by Ohio Gathering due to equity method accounting. (2) Includes the amortization expense associated with our favorable and unfavorable (for 2018) gas gathering contracts as reported in Other revenues. Cash paid for capital expenditures by reportable segment follow. Year ended December 31, 2019 2018 2017 (In thousands) Cash paid for capital expenditures (1): Utica Shale $ 3,902 $ 5,719 $ 22,921 Williston Basin 30,861 25,202 17,309 DJ Basin 80,487 64,920 7,150 Permian Basin 44,955 83,823 56,020 Piceance Basin 1,946 7,887 16,564 Barnett Shale (2) 184 1,370 569 Marcellus Shale 693 1,030 641 Total reportable segment capital expenditures 163,028 189,951 121,174 Corporate and Other 19,263 10,635 3,041 Total cash paid for capital expenditures $ 182,291 $ 200,586 $ 124,215 (1) Excludes cash paid for capital expenditures by Ohio Gathering due to equity method accounting. (2) For the year ended December 31, 2019, the amount includes sales tax reimbursements of $1.1 million.
Schedule of counterparties accounting for more than 10% of total revenues	Counterparties accounting for more than 10% of total revenues were as follows: Three months ended March 31, 2020 2019 Percentage of total revenues (1): Counterparty A - Piceance Basin 11 % * (1) Excludes revenues earned by Ohio Gathering due to equity method accounting. * Less than 10%	Counterparties accounting for more than 10% of total revenues were as follows: Year ended December 31, 2019 2018 2017 Percentage of total revenues (1): Counterparty A - Piceance Basin 11 % * * Counterparty B - Williston Basin 10 % * 13 % Counterparty C - Piceance Shale * 10 % * (1) Excludes revenues earned by Ohio Gathering due to equity method accounting. * Less than 10%
Reconciliation of net income to adjusted EBITDA	Segment adjusted EBITDA by reportable segment follows. Three months ended March 31, 2020 2019 (In thousands) Reportable segment adjusted EBITDA Utica Shale $ 5,928 $ 6,193 Ohio Gathering 7,939 9,210 Williston Basin 16,192 18,734 DJ Basin 5,911 2,673 Permian Basin 1,581 (550 ) Piceance Basin 23,557 25,999 Barnett Shale 8,760 11,374 Marcellus Shale 5,320 5,142 Total of reportable segments’ measures of profit $ 75,188 $ 78,775 A reconciliation of income or loss before income taxes and income or loss from equity method investees to total of reportable segments’ measures of profit or loss follows. Three months ended March 31, 2020 2019 (In thousands) Reconciliation of income (loss) before income taxes and income (loss) from equity method investees to total of reportable segments’ measures of profit: Income (loss) before income taxes and income (loss) from equity method investees $ 438 $ (39,582 ) Add: Corporate and Other expense 12,077 16,650 Interest expense 23,828 22,742 Depreciation and amortization 29,900 28,153 Proportional adjusted EBITDA for equity method investees 7,939 9,210 Adjustments related to MVC shortfall payments (5,442 ) (4,199 ) Adjustments related to capital reimbursement activity (211 ) (715 ) Unit-based and noncash compensation 2,723 2,526 Loss (gain) on asset sales, net 115 (961 ) Long-lived asset impairment 3,821 44,951 Total of reportable segments’ measures of profit $ 75,188 $ 78,775	Segment adjusted EBITDA by reportable segment follows. Year ended December 31, 2019 2018 2017 (In thousands) Reportable segment adjusted EBITDA Utica Shale $ 29,292 $ 30,285 $ 34,011 Ohio Gathering 39,126 39,969 41,246 Williston Basin 69,437 76,701 66,413 DJ Basin 18,668 7,558 6,624 Permian Basin (879 ) (1,200 ) — Piceance Basin 98,765 111,042 111,113 Barnett Shale 43,043 43,268 46,232 Marcellus Shale 20,051 24,267 23,888 Total of reportable segments’ measures of profit $ 317,503 $ 331,890 $ 329,527 A reconciliation of income or loss before income taxes and income or loss from equity method investees to total of reportable segments’ measures of profit or loss follows. Year ended December 31, 2019 2018 2017 (In thousands) Reconciliation of (loss) income before income taxes and loss from equity method investees to total of reportable segments’ measures of profit: (Loss) income before income taxes and loss from equity method investees $ (54,644 ) $ 45,575 $ (134,187 ) Add: Corporate and Other expense 44,808 45,131 40,803 Interest expense 91,966 82,830 88,701 Early extinguishment of debt — — 22,039 Depreciation and amortization 111,574 106,930 115,118 Proportional adjusted EBITDA for equity method investees 39,126 39,969 41,246 Adjustments related to MVC shortfall payments 3,476 (3,632 ) (41,373 ) Adjustments related to capital reimbursement activity (2,156 ) (427 ) — Unit-based and noncash compensation 8,171 8,328 7,951 (Gain) loss on asset sales, net (1,536 ) — 527 Long-lived asset impairment 60,507 7,186 188,702 Goodwill impairment 16,211 — — Total of reportable segments’ measures of profit $ 317,503 $ 331,890 $ 329,527
Schedule of Adjustments Related to Minimum Volume Commitments Shortfall Payments	Adjustments related to MVC shortfall payments by reportable segment follow. Three months ended March 31, 2020 Williston Basin Piceance Basin Barnett Shale Total (In thousands) Adjustments related to expected MVC shortfall payments: $ (5,665 ) $ 223 $ — $ (5,442 ) Three months ended March 31, 2019 Williston Basin Piceance Basin Barnett Shale Total (In thousands) Adjustments related to expected MVC shortfall payments: $ (5,549 ) $ (103 ) $ 1,453 $ (4,199 )	Adjustments related to MVC shortfall payments by reportable segment follow. Year ended December 31, 2019 Williston Basin Piceance Basin Barnett Shale Total (In thousands) Adjustments related to expected MVC shortfall payments: $ — $ (103 ) $ 3,579 $ 3,476 Year ended December 31, 2018 Williston Basin Piceance Basin Barnett Shale Total (In thousands) Adjustments related to expected MVC shortfall payments: $ — $ 10 $ (3,642 ) $ (3,632 ) Year Ended December 31, 2017 Williston Basin Piceance Basin Barnett Shale Total (In thousands) Adjustments related to MVC shortfall payments: Net change in deferred revenue for MVC shortfall payments $ (37,693 ) $ (3,065 ) $ — $ (40,758 ) Expected MVC shortfall adjustments — (3 ) (612 ) (615 ) Total adjustments related to MVC shortfall payments $ (37,693 ) $ (3,068 ) $ (612 ) $ (41,373 )

PROPERTY, PLANT, AND EQUIPMEN_2

PROPERTY, PLANT, AND EQUIPMENT, NET (Tables)	3 Months Ended	12 Months Ended
PROPERTY, PLANT, AND EQUIPMENT, NET (Tables)	Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Schedule of property, plant, and equipment, net	Details on property, plant and equipment follow. March 31, 2020 December 31, 2019 (In thousands) Gathering and processing systems and related equipment $ 2,193,225 $ 2,182,950 Construction in progress 73,040 78,716 Land and line fill 10,440 10,137 Other 59,014 54,595 Total 2,335,719 2,326,398 Less accumulated depreciation 465,636 443,909 Property, plant and equipment, net $ 1,870,083 $ 1,882,489	Details on property, plant and equipment follow. December 31, 2019 December 31, 2018 (In thousands) Gathering and processing systems and related equipment $ 2,182,950 $ 2,155,325 Construction in progress 78,716 137,920 Land and line fill 10,137 11,748 Other 54,595 47,319 Total 2,326,398 2,352,312 Less accumulated depreciation 443,909 388,213 Property, plant and equipment, net $ 1,882,489 $ 1,964,099
Schedule of long-lived asset impairments		During 2019, 2018 and 2017, we recognized the following long-lived asset impairments, by segment. Year ended December 31, 2019 2018 2017 (In thousands) Long-lived asset impairment: Williston Basin $ 10 $ 3,972 $ 101,961 Piceance Basin 14,162 1,004 697 DJ Basin 34,913 9 — Barnett Shale 9,629 — — Utica Shale — 1,440 878 Permian Basin 726 761 —
Schedule of depreciation expense and capitalized interest costs	Depreciation expense and capitalized interest follow. Three months ended March 31, 2020 2019 (In thousands) Depreciation expense $ 21,698 $ 19,820 Capitalized interest 491 1,915	Depreciation expense and capitalized interest follow. Year ended December 31, 2019 2018 2017 (In thousands) Depreciation expense $ 78,489 $ 74,674 $ 75,382 Capitalized interest 6,974 8,497 2,579

AMORTIZING INTANGIBLE ASSETS (T

AMORTIZING INTANGIBLE ASSETS (Tables)	3 Months Ended	12 Months Ended
AMORTIZING INTANGIBLE ASSETS (Tables)	Mar. 31, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	Details regarding our intangible assets, all of which are subject to amortization, follow: March 31, 2020 Gross carrying Accumulated Net (In thousands) Favorable gas gathering contracts $ 24,195 $ (15,359 ) $ 8,836 Contract intangibles 278,448 (175,973 ) 102,475 Rights-of-way 157,175 (44,410 ) 112,765 Total intangible assets $ 459,818 $ (235,742 ) $ 224,076 December 31, 2019 Gross carrying Accumulated Net (In thousands) Favorable gas gathering contracts $ 24,195 $ (15,125 ) $ 9,070 Contract intangibles 278,448 (169,549 ) 108,899 Rights-of-way 157,175 (42,866 ) 114,309 Total intangible assets $ 459,818 $ (227,540 ) $ 232,278	Details regarding our intangible assets, all of which are subject to amortization, follow. December 31, 2019 Gross carrying Accumulated Net (In thousands) Favorable gas gathering contracts $ 24,195 $ (15,125 ) $ 9,070 Contract intangibles 278,448 (169,549 ) 108,899 Rights-of-way 157,175 (42,866 ) 114,309 Total intangible assets $ 459,818 $ (227,540 ) $ 232,278 December 31, 2018 Gross carrying Accumulated Net (In thousands) Favorable gas gathering contracts $ 24,195 $ (13,905 ) $ 10,290 Contract intangibles 278,448 (143,962 ) 134,486 Rights-of-way 166,209 (37,569 ) 128,640 Total intangible assets $ 468,852 $ (195,436 ) $ 273,416
Recognized amortization expense in other revenues and cost and expenses	We recognized amortization expense in Other revenues as follows: Three months ended March 31, 2020 2019 (In thousands) Amortization expense – favorable gas gathering contracts $ (234 ) $ (389 ) We recognized amortization expense in costs and expenses as follows: Three months ended March 31, 2020 2019 (In thousands) Amortization expense – contract intangibles $ 6,424 $ 6,397 Amortization expense – rights-of-way 1,544 1,547	We recognized amortization expense in Other revenues as follows: Year ended December 31, 2019 2018 2017 (In thousands) Amortization expense – favorable gas gathering contracts $ (1,220 ) $ (1,555 ) $ (1,555 ) We recognized amortization expense in costs and expenses as follows: Year ended December 31, 2019 2018 2017 (In thousands) Amortization expense – contract intangibles $ 25,587 $ 26,141 $ 34,202 Amortization expense – rights-of-way 6,278 6,448 6,153
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The estimated aggregate annual amortization expected to be recognized for the remainder of 2020 and each of the four succeeding fiscal years follows. Intangible assets (In thousands) 2020 $ 23,926 2021 28,209 2022 25,142 2023 25,088 2024 14,917	The estimated aggregate annual amortization expected to be recognized for as of December 31, 2019 for each of the five succeeding fiscal years follows. Intangible assets (In thousands) 2020 $ 31,901 2021 28,209 2022 25,142 2023 25,088 2024 14,917

GOODWILL (Tables)

GOODWILL (Tables)	12 Months Ended
GOODWILL (Tables)	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Rollforward of goodwill by reportable segment	Accumulated goodwill impairments by reportable segment for those reporting units that have previously recognized goodwill follow. Year ended December 31, 2019 2018 2017 (In thousands) Accumulated goodwill impairment: Piceance Basin $ 45,478 $ 45,478 $ 45,478 Williston Basin 257,572 257,572 257,572 Marcellus Shale 16,211 — — Total accumulated goodwill impairment $ 319,261 $ 303,050 $ 303,050

EQUITY METHOD INVESTMENTS (Tabl

EQUITY METHOD INVESTMENTS (Tables)	3 Months Ended	12 Months Ended
EQUITY METHOD INVESTMENTS (Tables)	Mar. 31, 2020	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments	A reconciliation of our 38.5% ownership interest in Ohio Gathering to our investment per Ohio Gathering’s books and records follows (in thousands). Investment in Ohio Gathering, March 31, 2020 $ 271,268 March cash distributions 1,875 Basis difference 223,151 Investment in Ohio Gathering February 29, 2020 $ 496,294 As noted in our 2019 Annual Report, in December 2019 an impairment loss of long-lived assets was recognized by OCC which brought our investment in OCC to zero. As a result, we have not recorded our portion of OCC’s net loss for the three months ended March 31, 2020 in the Income (loss) from equity method investees caption of our unaudited condensed consolidated statements of operations. Summarized statements of operations information for OGC and Three months ended February 29, 2020 Three months ended February 28, 2019 OGC OCC OGC OCC (In thousands) Total revenues $ 30,068 $ 2,727 $ 33,466 $ 2,266 Total operating expenses 25,750 30,855 25,487 2,973 Net income (loss) 4,311 (28,128 ) 7,972 (707 )	A reconciliation of our 38.5% and 40% ownership interest in Ohio Gathering to our investment per Ohio Gathering’s books and records follows for the years ending December 31, 2019 and 2018, respectively (in thousands). 2019 2018 (In thousands) Investment in Ohio Gathering, December 31 $ 275,000 $ 649,250 December cash distributions 2,700 2,736 Impairment loss (1) 232,521 5,652 Loss contingency — 2,040 Basis difference — (116,832 ) Investment in Ohio Gathering, net of basis difference, November 30 $ 510,221 $ 542,846 (1) Amount is comprised of (i) a $329.7 million impairment of our equity method investment in Ohio Gathering; (ii) the write-off Summarized balance sheet information for OGC and OCC follows (amounts represent 100% of investee financial information). November 30, 2019 November 30, 2018 OGC OCC OGC OCC (In thousands) Current assets $ 41,972 $ 2,187 $ 37,403 $ 3,716 Noncurrent assets 1,281,171 28,323 1,262,253 27,203 Total assets $ 1,323,143 $ 30,510 $ 1,299,656 $ 30,919 Current liabilities $ 21,798 $ 4,016 $ 19,903 $ 3,912 Noncurrent liabilities 4,113 6,683 3,688 8,807 Total liabilities $ 25,911 $ 10,699 $ 23,591 $ 12,719 Summarized statements of operations information for OGC and OCC follow (amounts represent 100% of investee financial information). Twelve months ended November 30, 2019 Twelve months ended November 30, 2018 Twelve months ended November 30, 2017 OGC OCC OGC OCC OGC OCC (In thousands) Total revenues $ 142,138 $ 8,601 $ 142,398 $ 10,177 $ 140,679 $ 8,607 Total operating expenses 108,234 38,815 136,722 9,053 111,897 8,298 Net income (loss) 33,897 (30,214 ) 5,670 498 28,785 (907 )

DEFERRED REVENUE (Tables)

DEFERRED REVENUE (Tables)	3 Months Ended	12 Months Ended
DEFERRED REVENUE (Tables)	Mar. 31, 2020	Dec. 31, 2019
Revenue From Contract With Customer [Abstract]
Rollforward of deferred revenue	A rollforward of current deferred revenue follows. Utica Williston DJ Basin Piceance Basin Barnett Marcellus Total (In thousands) Current deferred revenue, January 1, 2020 $ 18 $ 1,933 $ 2,860 $ 7,014 $ 1,630 $ 38 $ 13,493 Additions 2 483 2,123 1,547 396 9 4,560 Less revenue recognized 5 483 1,285 1,544 409 9 3,735 Current deferred revenue, March 31, 2020 $ 15 $ 1,933 $ 3,698 $ 7,017 $ 1,617 $ 38 $ 14,318 A rollforward of noncurrent deferred revenue follows. Utica Williston DJ Piceance Basin Barnett Marcellus Total (In thousands) Noncurrent deferred revenue, January 1, 2020 $ 3 $ 3,634 $ 7,589 $ 17,710 $ 9,575 $ 198 $ 38,709 Additions 425 3,522 3,263 1,304 382 — 8,896 Less reclassification to current deferred revenue 2 483 2,123 1,547 396 9 4,560 Noncurrent deferred revenue, March 31, 2020 $ 426 $ 6,673 $ 8,729 $ 17,467 $ 9,561 $ 189 $ 43,045	A rollforward of current deferred revenue follows. Utica Shale Williston DJ Basin Piceance Basin Barnett Marcellus Total (In thousands) Current deferred revenue, January 1, 2018 $ 18 $ 1,017 $ 358 $ 7,038 $ 1,619 $ 38 $ 10,088 Additions 18 1,744 943 21,955 1,651 96 26,407 Less revenue recognized 18 1,347 562 21,377 1,628 96 25,028 Current deferred revenue, December 31, 2018 18 1,414 739 7,616 1,642 38 11,467 Additions 18 2,262 5,165 16,211 1,632 38 25,326 Less revenue recognized 18 1,743 3,044 16,813 1,644 38 23,300 Current deferred revenue, December 31, 2019 $ 18 $ 1,933 $ 2,860 $ 7,014 $ 1,630 $ 38 $ 13,493 A rollforward of noncurrent deferred revenue follows. Utica Shale Williston DJ Basin Piceance Basin Barnett Marcellus Total (In thousands) Noncurrent deferred, revenue, January 1, 2018 $ 39 $ 4,215 $ 4,505 $ 18,219 $ 8,217 $ 333 $ 35,528 Additions — 1,851 3,720 7,869 3,062 — 16,502 Less reclassification to current deferred revenue 18 1,673 941 8,146 1,651 97 12,526 Noncurrent deferred revenue, December 31, 2018 21 4,393 7,284 17,942 9,628 236 39,504 Additions — 1,940 5,470 6,104 1,579 — 15,093 Less reclassification to current deferred revenue 18 2,699 5,165 6,336 1,632 38 15,888 Noncurrent deferred revenue, December 31, 2019 $ 3 $ 3,634 $ 7,589 $ 17,710 $ 9,575 $ 198 $ 38,709

DEBT (Tables)

DEBT (Tables)	3 Months Ended	12 Months Ended
DEBT (Tables)	Mar. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of debt and capital leases	Debt consisted of the following: March 31, 2020 December 31, 2019 (In thousands) Summit Holdings’ variable rate senior secured Revolving Credit Facility (3.74% at March 31, 2020 and 4.55% at December 31, 2019) due May 2022 $ 698,000 $ 677,000 Summit Holdings’ 5.5% senior unsecured notes due August 2022 300,000 300,000 Less unamortized debt issuance costs (1) (1,521 ) (1,686 ) Summit Holdings’ 5.75% senior unsecured notes due April 2025 500,000 500,000 Less unamortized debt issuance costs (1) (4,763 ) (5,015 ) SMP Holdings’ variable rate senior secured term loan (7.00% at March 31, 2020 and 7.80% at December 31, 2019) due May 2022 160,750 161,500 Less unamortized debt issuance costs (1) (3,601 ) (3,974 ) Total debt 1,648,865 1,627,825 Less current portion 7,800 5,546 Total long-term debt $ 1,641,065 $ 1,622,279 (1) Issuance costs are being amortized over the life of the Term Loan B and Senior Notes.	Debt consisted of the following: December 31, 2019 December 31, 2018 (In thousands) Summit Holdings’ variable rate senior secured ( $ 677,000 $ 466,000 Summit Holdings’ 5.5% senior unsecured notes due August 2022 300,000 300,000 Less unamortized debt issuance costs (1) (1,686 ) (2,362 ) Summit Holdings’ 5.75% senior unsecured notes due April 2025 500,000 500,000 Less unamortized debt issuance costs (1) (5,015 ) (5,907 ) SMP Holdings’ variable rate senior secured term loan ( 161,500 226,750 Less unamortized debt issuance costs (1) (3,974 ) (5,701 ) Total debt 1,627,825 1,478,780 Less current portion 5,546 14,500 Total long-term debt $ 1,622,279 $ 1,464,280 (1) Issuance costs are being amortized over the life of the Term Loan B
Schedule of maturities of long-term debt		The aggregate amount of debt maturing during each of the years after December 31, 2019 are as follows (in thousands): 2020 $ — 2021 — 2022 1,138,500 2023 — 2024 — Thereafter 500,000 Total long-term debt $ 1,638,500

FINANCIAL INSTRUMENTS (Tables)

FINANCIAL INSTRUMENTS (Tables)	3 Months Ended	12 Months Ended
FINANCIAL INSTRUMENTS (Tables)	Mar. 31, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Summary of the estimated fair value of debt instruments	A summary of the estimated fair value of our debt financial instruments follows. March 31, 2020 December 31, 2019 Carrying value Estimated fair value (Level 2) Carrying value Estimated fair value (Level 2) (In thousands) Summit Holdings 5.5% Senior Notes ($300.0 million principal) $ 298,479 $ 58,875 $ 298,314 $ 266,750 Summit Holdings 5.75% Senior Notes ($500.0 million principal) 495,237 53,125 494,985 382,708	A summary of the estimated fair value of our debt financial instruments follows. December 31, 2019 December 31, 2018 Carrying value Estimated fair value (Level 2) Carrying value Estimated fair value (Level 2) (In thousands) Summit Holdings 5.5% Senior Notes ($300.0 million principal) $ 298,314 $ 266,750 $ 297,638 $ 286,625 Summit Holdings 5.75% Senior Notes ($500.0 million principal) 494,985 382,708 494,093 455,208

PARTNERS' CAPITAL AND MEZZANI_2

PARTNERS' CAPITAL AND MEZZANINE CAPITAL (Tables)	3 Months Ended	12 Months Ended
PARTNERS' CAPITAL AND MEZZANINE CAPITAL (Tables)	Mar. 31, 2020	Dec. 31, 2019
Equity [Abstract]
Details of cash distributions	Prior to the GP Buy-In Transaction, SMLP per-unit during the three months ended March 31 (All payments represent per-unit distributions based on the SMLP common units outstanding prior to the GP Buy-In Transaction): Three months ended March 31, 2020 2019 Per-unit $ 0.125 $ 0.575	Year ended December 31, 2019 2018 2017 Per-unit $ 1.4375 $ 2.300 $ 2.300

EARNINGS PER UNIT (Tables)

EARNINGS PER UNIT (Tables)	3 Months Ended	12 Months Ended
EARNINGS PER UNIT (Tables)	Mar. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table details the components of EPU. Three months ended March 31, 2020 2019 (In thousands, except per-unit amounts) Numerator for basic and diluted EPU: Allocation of net income (loss) among limited partner interests: Net income (loss) attributable to limited partners $ 5,643 $ (14,710 ) Less net income attributable to Series A Preferred Units 7,125 7,125 Less net income attributable to Subsidiary Series A Preferred Units 945 — Net loss attributable to common limited partners $ (2,427 ) $ (21,835 ) Denominator for basic and diluted EPU: Weighted-average common units outstanding – basic and diluted (1) 45,319 45,319 Loss per limited partner unit: Common unit – basic $ (0.05 ) $ (0.48 ) Common unit – diluted $ (0.05 ) $ (0.48 ) Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU 1,889 34 (1) As a result of the GP Buy-In	The following table details the components of EPU. Year ended December 31, 2019 2018 2017 (In thousands, except per-unit Numerator for basic and diluted EPU: Allocation of net (loss) income among limited partner interests: Net (loss) income attributable to limited partners $ (184,451 ) $ 31,546 $ (183,411 ) Less net income attributable to Series A Preferred Units 28,500 28,500 3,563 Less net income attributable to Subsidiary Series A Preferred Units 58 — — Net (loss) income attributable to common limited partners $ (213,009 ) $ 3,046 $ (186,974 ) Denominator for basic and diluted EPU: Weighted-average common units outstanding – basic (1) 45,319 45,319 45,319 Effect of nonvested phantom units — 311 — Weighted-average common units outstanding – diluted 45,319 45,630 45,319 (Loss) earnings per limited partner unit: Common unit – basic $ (4.70 ) $ 0.07 $ (4.13 ) Common unit – diluted $ (4.70 ) $ 0.07 $ (4.13 ) Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU 175 2 42 (1) As a result of the GP Buy-In

UNIT-BASED AND NONCASH COMPEN_2

UNIT-BASED AND NONCASH COMPENSATION (Tables)	12 Months Ended
UNIT-BASED AND NONCASH COMPENSATION (Tables)	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of activity	The following table presents phantom unit activity: Units Weighted-average Nonvested phantom units, January 1, 2017 691,955 $ 19.59 Phantom units granted 371,972 22.50 Phantom units vested (293,222 ) 24.76 Phantom units forfeited (21,431 ) 20.07 Nonvested phantom units, December 31, 2017 749,274 20.07 Phantom units granted 515,358 15.25 Phantom units vested (359,016 ) 22.39 Phantom units forfeited (41,492 ) 17.27 Nonvested phantom units, December 31, 2018 864,124 17.11 Phantom units granted 1,913,099 6.48 Phantom units vested (602,617 ) 16.78 Phantom units forfeited (68,611 ) 12.87 Nonvested phantom units, December 31, 2019 2,105,995 $ 7.69
Schedule of intrinsic values	The intrinsic value of phantom units that vested during the years ended December 31, follows. Year ended December 31, 2019 2018 2017 (In thousands) Intrinsic value of vested LTIP awards $ 5,940 $ 5,393 $ 6,657
Schedule of unit-based compensation recognized in general and administrative expense	Unit-based compensation recognized in general and administrative expense related to awards under the SMLP LTIP follows. Year ended December 31, 2019 2018 2017 (In thousands) SMLP LTIP unit-based compensation $ 8,171 $ 8,328 $ 7,951

LEASES, COMMITMENTS AND CONTI_2

LEASES, COMMITMENTS AND CONTINGENCIES (Tables)	3 Months Ended	12 Months Ended
LEASES, COMMITMENTS AND CONTINGENCIES (Tables)	Mar. 31, 2020	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Schedule of right-of-use assets and lease liabilities	ROU assets (included in the Property, plant and equipment, net caption on our unaudited condensed consolidated balance sheet) and lease liabilities (included in the Other current liabilities and Other noncurrent liabilities captions on our unaudited condensed consolidated balance sheet) follow: March 31, 2020 December 31, 2019 (In thousands) ROU assets Operating $ 4,306 $ 3,580 Finance 2,649 3,159 $ 6,955 $ 6,739 Lease liabilities, current Operating $ 967 $ 1,221 Finance 1,023 1,246 $ 1,990 $ 2,467 Lease liabilities, noncurrent Operating $ 3,482 $ 2,513 Finance 483 676 $ 3,965 $ 3,189	ROU assets (included in the Property, plant and equipment, net caption on our consolidated balance sheet) and lease liabilities (included in the Other current liabilities and Other noncurrent liabilities captions on our consolidated balance sheet) follow: December 31, 2019 (In thousands) ROU assets Operating $ 3,580 Finance 3,159 $ 6,739 Lease liabilities, current Operating $ 1,221 Finance 1,246 $ 2,467 Lease liabilities, noncurrent Operating $ 2,513 Finance 676 $ 3,189
Schedule of lease cost and other information	Lease cost and Other information follow: Three months ended March 31, 2020 2019 (In thousands) Lease cost Finance lease cost: Amortization of ROU assets (included in depreciation and amortization) $ 352 $ 368 Interest on lease liabilities (included in interest expense) 18 23 Operating lease cost (included in general and administrative expense) 772 832 $ 1,142 $ 1,223 Three months ended March 31, 2020 2019 (In thousands) Other information Cash paid for amounts included in the measurement of lease liabilities Operating cash outflows from operating leases $ 708 $ 821 Operating cash outflows from finance leases 18 23 Financing cash outflows from finance leases 417 445 ROU assets obtained in exchange for new operating lease liabilities 1,199 — ROU assets obtained in exchange for new finance lease liabilities — 693 Weighted-average remaining lease term (years) - operating leases 6.0 3.5 Weighted-average remaining lease term (years) - finance leases 2.0 2.0 Weighted-average discount rate - operating leases 5 % 5 % Weighted-average discount rate - finance leases 4 % 4 %	Lease cost and Other information follow: Year ended December 31, 2019 (In thousands) Lease cost Finance lease cost: Amortization of ROU assets (included in depreciation and amortization) $ 1,559 Interest on lease liabilities (included in interest expense) 102 Operating lease cost (included in general and administrative expense) 3,345 $ 5,006 Twelve months ended December 31, 2019 (In thousands) Other information Cash paid for amounts included in the measurement of lease liabilities Operating cash outflows from operating leases $ 3,396 Operating cash outflows from finance leases 102 Financing cash outflows from finance leases 1,873 ROU assets obtained in exchange for new operating lease liabilities 1,218 ROU assets obtained in exchange for new finance lease liabilities 1,350 Weighted-average remaining lease term (years) - operating leases 5.8 Weighted-average remaining lease term (years) - finance leases 2.0 Weighted-average discount rate - operating leases 5 % Weighted-average discount rate - finance leases 4 %
Schedule of total rent expense related to operating leases	We recognize total lease expense incurred or allocated to us in general and administrative expenses. Lease expense related to operating leases, including lease expense incurred on our behalf and allocated to us, was as follows: Three months ended March 31, 2020 2019 (In thousands) Lease expense $ 953 $ 990	We recognize total lease expense incurred or allocated to us in general and administrative expenses. Lease expense related to operating leases, including lease expense incurred on our behalf and allocated to us, was as follows: Year ended December 31, 2019 2018 2017 (In thousands) Lease expense $ 4,038 $ 4,108 $ 3,963
Future minimum lease payments due and future minimum rentals to be received under noncancelable leases and subleases	Future minimum lease payments due under noncancelable leases for the remainder of 2020 and each of the five succeeding fiscal years and thereafter, were as follows: March 31, 2020 (In thousands) Operating Finance 2020 $ 1,046 $ 873 2021 1,125 606 2022 883 76 2023 741 — 2024 555 — 2025 464 — Thereafter 742 — Total future minimum lease payments $ 5,556 $ 1,555 Future minimum lease payments due under noncancelable leases at December 31, 2019 and each of the five succeeding fiscal years and thereafter, were as follows: December 31, 2019 (In thousands) Operating Finance 2020 $ 1,705 $ 1,299 2021 1,004 616 2022 551 76 2023 408 — 2024 240 — 2025 153 — Thereafter 742 — Total future minimum lease payments $ 4,803 $ 1,991	Future minimum lease payments due under noncancelable leases at December 31, 2019, were as follows December 31, 2019 (In thousands) Operating Finance 2020 $ 1,705 $ 1,299 2021 1,004 616 2022 551 76 2023 408 — 2024 240 — 2025 153 — Thereafter 742 — Total future minimum lease payments $ 4,803 $ 1,991
Future minimum lease payments due under noncancelable operating leases		Future minimum lease payments due under noncancelable operating leases (under ASC 840) at December 31, 2018, were as follows: December 31, 2018 (In thousands) 2019 $ 3,133 2020 1,018 2021 550 2022 506 2023 373 Thereafter 621 Total future minimum lease payments $ 6,201
Schedule of Future Payments Due Under Finance Leases		Future payments due under finance leases (under ASC 840) at December 31, 2018, were as follows: December 31, 2018 (In thousands) 2019 $ 1,473 2020 902 2021 174 Total finance lease obligations 2,549 Less: Amounts representing interest (104 ) Net present value of finance lease obligations 2,445 Less: Amount representing current portion (included in Other current liabilities) (1,406 ) Finance lease obligations, less current portion (included in Other noncurrent liabilities) $ 1,039
Schedule of accrued environmental remediation	A rollforward of the aggregate accrued environmental remediation liabilities follows. Total (In thousands) Accrued environmental remediation, January 1, 2020 $ 4,651 Payments made (17 ) Accrued environmental remediation, March 31, 2020 $ 4,634	A rollforward of the aggregate accrued environmental remediation liabilities follows. Total (In thousands) Accrued environmental remediation, January 1, 2018 $ 5,344 Payments made (3,808 ) Additional accruals 4,100 Accrued environmental remediation, December 31, 2018 $ 5,636 Payments made (2,284 ) Additional accruals 1,299 Accrued environmental remediation, December 31, 2019 $ 4,651

UNAUDITED QUARTERLY FINANCIAL_2

UNAUDITED QUARTERLY FINANCIAL DATA (Tables)	12 Months Ended
UNAUDITED QUARTERLY FINANCIAL DATA (Tables)	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly Summarized Information on Consolidated Results of Operations	Summarized information on the consolidated results of operations for each of the quarters during the two-year Quarter ended December 31, 2019 September 30, 2019 June 30, 2019 March 31, 2019 (In thousands, except per-unit Total revenues $ 112,247 $ 100,187 $ 99,686 $ 131,408 Net (loss) income attributable to SMLP $ (345,345 ) $ (11,129 ) $ 3,028 $ (40,280 ) Less net loss attributable to noncontrolling interest (172,024 ) (10,340 ) (1,341 ) (25,570 ) Less net income attributable to Series A Preferred Units 7,125 7,125 7,125 7,125 Less net income attributable to Subsidiary Series A Preferred Units 58 — — — Net loss attributable to common limited partners $ (180,504 ) $ (7,914 ) $ (2,756 ) $ (21,835 ) Loss per limited partner unit: Common unit - basic $ (3.98 ) $ (0.17 ) $ (0.06 ) $ (0.48 ) Common unit - diluted $ (3.98 ) $ (0.17 ) $ (0.06 ) $ (0.48 ) Quarter ended December 31, 2018 September 30, 2018 June 30, 2018 March 31, 2018 (In thousands, except per-unit Total revenues $ 133,671 $ 127,479 $ 128,183 $ 117,320 Net (loss) income attributable to SMLP $ (3,401 ) $ 14,353 $ 11,861 $ 11,507 Less net income (loss) attributable to noncontrolling interest 18,535 30,453 (37,712 ) (8,502 ) Less net income attributable to Series A Preferred Units 7,125 7,125 7,125 7,125 Net (loss) income attributable to common limited partners $ (29,061 ) $ (23,225 ) $ 42,448 $ 12,884 (Loss) earnings per limited partner unit: Common unit - basic $ (0.64 ) $ (0.51 ) $ 0.94 $ 0.28 Common unit - diluted $ (0.64 ) $ (0.51 ) $ 0.93 $ 0.28

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 31, 2019
Gathering and processing systems and related equipment \| Minimum
Property, Plant and Equipment [Line Items]
Useful life	12 years
Gathering and processing systems and related equipment \| Maximum
Property, Plant and Equipment [Line Items]
Useful life	30 years
Other \| Minimum
Property, Plant and Equipment [Line Items]
Useful life	4 years
Other \| Maximum
Property, Plant and Equipment [Line Items]
Useful life	15 years

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2020	Jan. 01, 2019
Summary of Significant Accounting Policies [Line Items]
Goodwill impairment	$ 16,200	$ 16,211	$ 0	$ 0
Goodwill		$ 0	$ 16,211
Long-term, fee-based contracts with original terms		up to 25 years
Right-of-use asset		$ 3,580			$ 4,306
Accounting Standard Update 2016-02
Summary of Significant Accounting Policies [Line Items]
Right-of-use asset						$ 5,400
Operating Lease, Liability						$ 5,400
General Partner \| Summit Midstream Partners, LP
Summary of Significant Accounting Policies [Line Items]
General partner interest		2.00%
Favorable gas gathering contracts \| Minimum
Summary of Significant Accounting Policies [Line Items]
Useful lives (In years)		10 years
Favorable gas gathering contracts \| Maximum
Summary of Significant Accounting Policies [Line Items]
Useful lives (In years)		20 years
Other Gas Gathering Contract \| Minimum
Summary of Significant Accounting Policies [Line Items]
Useful lives (In years)		3 years
Other Gas Gathering Contract \| Maximum
Summary of Significant Accounting Policies [Line Items]
Useful lives (In years)		25 years
Rights-of-way \| Minimum
Summary of Significant Accounting Policies [Line Items]
Useful lives (In years)		20 years
Rights-of-way \| Maximum
Summary of Significant Accounting Policies [Line Items]
Useful lives (In years)		30 years

REVENUE - Narrative1 (Details)

REVENUE - Narrative1 (Details) - Maximum	Mar. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue From Contract With Customer [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, Period		25 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-04-01
Revenue From Contract With Customer [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, Period	25 years

REVENUE - Narrative (Details)

REVENUE - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
REVENUE - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue From Contract With Customer [Line Items]
Revenue, performance obligation, description of payment terms	Our services are typically billed on a monthly basis and we do not offer extended payment terms. We do not have contracts with financing components.		Our services are typically billed on a monthly basis and we do not offer extended payment terms. We do not have contracts with financing components.
Receivables with customers	$ 58,000		$ 90,400	$ 82,900
Contract assets included in accounts receivable	17,354	$ 3,902	3,902	8,755	$ 0
Gathering Services and Related Fees
Revenue From Contract With Customer [Line Items]
Contract liabilities, revenue	$ 2,400	$ 2,700	$ 10,100	$ 10,800

REVENUE - Schedule of Estimated

REVENUE - Schedule of Estimated Revenue Expected to be Recognized and MVC Shortfall Payments (Details) - Gathering Services and Related Fees - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, Period		1 year
Revenue, remaining performance obligation		$ 122,055
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, Period	9 months
Revenue, remaining performance obligation	$ 86,916
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, Period	1 year	1 year
Revenue, remaining performance obligation	$ 102,127	$ 102,127
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, Period	1 year	1 year
Revenue, remaining performance obligation	$ 84,736	$ 84,736
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, Period	1 year	1 year
Revenue, remaining performance obligation	$ 66,693	$ 66,693
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, Period	1 year	1 year
Revenue, remaining performance obligation	$ 50,608	$ 50,608
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, Period	1 year	1 year
Revenue, remaining performance obligation	$ 58,672	$ 59,602

REVENUE - Schedule of Disaggreg

REVENUE - Schedule of Disaggregated Revenue by Geographic Area and Major Products and Services Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Total revenues	$ 104,903	$ 112,247	$ 100,187	$ 99,686	$ 131,408	$ 133,671	$ 127,479	$ 128,183	$ 117,320	$ 443,528	$ 506,653	$ 488,741
Reportable Segments
Disaggregation Of Revenue [Line Items]
Total revenues	104,260				107,891					415,906	428,492	469,224
Reportable Segments \| Utica Shale
Disaggregation Of Revenue [Line Items]
Total revenues	6,962				7,495					33,991	35,233	38,907
Reportable Segments \| Williston Basin
Disaggregation Of Revenue [Line Items]
Total revenues	31,263				34,199					105,651	123,650	161,503
Reportable Segments \| DJ Basin
Disaggregation Of Revenue [Line Items]
Total revenues	7,959				4,816					26,050	15,294	11,860
Reportable Segments \| Piceance Basin
Disaggregation Of Revenue [Line Items]
Total revenues	29,257				35,280					133,638	155,519	154,893
Reportable Segments \| Permian Basin
Disaggregation Of Revenue [Line Items]
Total revenues	7,010				4,619					20,303	958	0
Reportable Segments \| Barnett Shale
Disaggregation Of Revenue [Line Items]
Total revenues	15,574				15,285					71,802	68,265	71,667
Reportable Segments \| Marcellus Shale
Disaggregation Of Revenue [Line Items]
Total revenues	6,235				6,197					24,471	29,573	$ 30,394
Reportable Segments \| All Other Segments
Disaggregation Of Revenue [Line Items]
Total revenues	643				23,517					27,622	78,161
Gathering Services and Related Fees
Disaggregation Of Revenue [Line Items]
Total revenues	83,792				86,964					326,747	344,616
Gathering Services and Related Fees \| Reportable Segments
Disaggregation Of Revenue [Line Items]
Total revenues	83,792				88,353					328,792	350,618
Gathering Services and Related Fees \| Reportable Segments \| Utica Shale
Disaggregation Of Revenue [Line Items]
Total revenues	6,962				7,495					31,926	35,233
Gathering Services and Related Fees \| Reportable Segments \| Williston Basin
Disaggregation Of Revenue [Line Items]
Total revenues	23,797				25,706					77,626	79,606
Gathering Services and Related Fees \| Reportable Segments \| DJ Basin
Disaggregation Of Revenue [Line Items]
Total revenues	6,855				3,724					21,940	11,251
Gathering Services and Related Fees \| Reportable Segments \| Piceance Basin
Disaggregation Of Revenue [Line Items]
Total revenues	27,189				31,840					121,357	135,810
Gathering Services and Related Fees \| Reportable Segments \| Permian Basin
Disaggregation Of Revenue [Line Items]
Total revenues	2,311				366					3,610	115
Gathering Services and Related Fees \| Reportable Segments \| Barnett Shale
Disaggregation Of Revenue [Line Items]
Total revenues	10,443				13,025					47,862	59,030
Gathering Services and Related Fees \| Reportable Segments \| Marcellus Shale
Disaggregation Of Revenue [Line Items]
Total revenues	6,235				6,197					24,471	29,573
Gathering Services and Related Fees \| Reportable Segments \| All Other Segments
Disaggregation Of Revenue [Line Items]
Total revenues	0				(1,389)					(2,045)	(6,002)
Natural Gas, NGLs and Condensate Sales
Disaggregation Of Revenue [Line Items]
Total revenues	13,780				37,928					86,994	134,834
Natural Gas, NGLs and Condensate Sales \| Reportable Segments
Disaggregation Of Revenue [Line Items]
Total revenues	13,780				12,797					58,334	50,377
Natural Gas, NGLs and Condensate Sales \| Reportable Segments \| Utica Shale
Disaggregation Of Revenue [Line Items]
Total revenues	0				0					0	0
Natural Gas, NGLs and Condensate Sales \| Reportable Segments \| Williston Basin
Disaggregation Of Revenue [Line Items]
Total revenues	4,324				5,585					16,461	31,840
Natural Gas, NGLs and Condensate Sales \| Reportable Segments \| DJ Basin
Disaggregation Of Revenue [Line Items]
Total revenues	70				85					389	371
Natural Gas, NGLs and Condensate Sales \| Reportable Segments \| Piceance Basin
Disaggregation Of Revenue [Line Items]
Total revenues	1,003				2,302					7,954	14,800
Natural Gas, NGLs and Condensate Sales \| Reportable Segments \| Permian Basin
Disaggregation Of Revenue [Line Items]
Total revenues	4,512				4,221					16,383	843
Natural Gas, NGLs and Condensate Sales \| Reportable Segments \| Barnett Shale
Disaggregation Of Revenue [Line Items]
Total revenues	3,871				604					17,147	2,523
Natural Gas, NGLs and Condensate Sales \| Reportable Segments \| Marcellus Shale
Disaggregation Of Revenue [Line Items]
Total revenues	0				0					0	0
Natural Gas, NGLs and Condensate Sales \| Reportable Segments \| All Other Segments
Disaggregation Of Revenue [Line Items]
Total revenues	0				25,131					28,660	84,457
Other Revenues
Disaggregation Of Revenue [Line Items]
Total revenues	7,331				6,516					29,787	27,203
Other Revenues \| Reportable Segments
Disaggregation Of Revenue [Line Items]
Total revenues	6,688				6,741					28,780	27,497
Other Revenues \| Reportable Segments \| Utica Shale
Disaggregation Of Revenue [Line Items]
Total revenues	0				0					2,065	0
Other Revenues \| Reportable Segments \| Williston Basin
Disaggregation Of Revenue [Line Items]
Total revenues	3,142				2,908					11,564	12,204
Other Revenues \| Reportable Segments \| DJ Basin
Disaggregation Of Revenue [Line Items]
Total revenues	1,034				1,007					3,721	3,672
Other Revenues \| Reportable Segments \| Piceance Basin
Disaggregation Of Revenue [Line Items]
Total revenues	1,065				1,138					4,327	4,909
Other Revenues \| Reportable Segments \| Permian Basin
Disaggregation Of Revenue [Line Items]
Total revenues	187				32					310	0
Other Revenues \| Reportable Segments \| Barnett Shale
Disaggregation Of Revenue [Line Items]
Total revenues	1,260				1,656					6,793	6,712
Other Revenues \| Reportable Segments \| Marcellus Shale
Disaggregation Of Revenue [Line Items]
Total revenues	0				0					0	0
Other Revenues \| Reportable Segments \| All Other Segments
Disaggregation Of Revenue [Line Items]
Total revenues	$ 643				$ (225)					$ 1,007	$ (294)

REVENUE - Schedule of Informati

REVENUE - Schedule of Information about Contract Assets from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Contract with Customer, Asset and Liability [Abstract]
Contract assets, beginning of period	$ 3,902	$ 8,755	$ 8,755	$ 0
Additions	13,877	18,077	18,077	26,403
Transfers out	(425)	(22,930)	(22,930)	(17,648)
Contract assets, end of period	$ 17,354	$ 3,902	$ 3,902	$ 8,755

SEGMENT INFORMATION - Assets, R

SEGMENT INFORMATION - Assets, Revenues, Depreciation and Amortization, and Capital Expenditures by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Assets	$ 2,626,297	$ 2,574,098				$ 3,033,219				$ 2,574,098	$ 3,033,219	$ 2,907,719
Revenues	104,903	112,247	$ 100,187	$ 99,686	$ 131,408	133,671	$ 127,479	$ 128,183	$ 117,320	443,528	506,653	488,741
Depreciation and amortization	29,900				28,153					111,574	106,930	115,118
Capital expenditures	18,583				60,848					182,291	200,586	124,215
Reportable Segments
Segment Reporting Information [Line Items]
Assets	2,465,739	2,490,945				2,980,700				2,490,945	2,980,700	2,872,636
Revenues	104,260				107,891					415,906	428,492	469,224
Depreciation and amortization	28,924				27,619					108,822	105,024	113,754
Capital expenditures	16,856				44,747					163,028	189,951	121,174
Reportable Segments \| Utica Shale
Segment Reporting Information [Line Items]
Assets	205,341	206,368				207,357				206,368	207,357	212,311
Revenues	6,962				7,495					33,991	35,233	38,907
Depreciation and amortization	1,927				1,908					7,659	7,672	7,009
Capital expenditures	909				101					3,902	5,719	22,921
Reportable Segments \| Ohio Gathering
Segment Reporting Information [Line Items]
Assets	271,268	275,000				649,250				275,000	649,250	690,485
Reportable Segments \| Williston Basin
Segment Reporting Information [Line Items]
Assets	452,684	452,152				526,819				452,152	526,819	512,860
Revenues	31,263				34,199					105,651	123,650	161,503
Depreciation and amortization	6,495				5,436					19,829	22,642	33,772
Capital expenditures	4,943				8,023					30,861	25,202	17,309
Reportable Segments \| Barnett Shale
Segment Reporting Information [Line Items]
Assets	345,248	350,638				376,564				350,638	376,564	383,306
Revenues	15,574				15,285					71,802	68,265	71,667
Depreciation and amortization	4,032				4,330					16,575	15,325	15,001
Capital expenditures	657				(118)					184	1,370	569
Reportable Segments \| Marcellus Shale
Segment Reporting Information [Line Items]
Assets	184,279	184,631				208,790				184,631	208,790	217,362
Revenues	6,235				6,197					24,471	29,573	30,394
Depreciation and amortization	2,300				2,283					9,141	9,090	9,047
Capital expenditures	422				102					693	1,030	641
Reportable Segments \| DJ Basin
Segment Reporting Information [Line Items]
Assets	200,473	205,308				166,580				205,308	166,580	79,438
Revenues	7,959				4,816					26,050	15,294	11,860
Depreciation and amortization	1,527				799					3,732	3,133	2,636
Capital expenditures	6,298				28,356					80,487	64,920	7,150
Reportable Segments \| Permian Basin
Segment Reporting Information [Line Items]
Assets	184,043	185,708				145,702				185,708	145,702	57,590
Revenues	7,010				4,619					20,303	958	0
Depreciation and amortization	1,345				1,072					4,868	243	0
Capital expenditures	3,281				7,057					44,955	83,823	56,020
Reportable Segments \| Piceance Basin
Segment Reporting Information [Line Items]
Assets	622,403	631,140				699,638				631,140	699,638	719,284
Revenues	29,257				35,280					133,638	155,519	154,893
Depreciation and amortization	11,298				11,791					47,018	46,919	46,289
Capital expenditures	346				1,226					1,946	7,887	16,564
Corporate and Other
Segment Reporting Information [Line Items]
Assets	160,558	83,153				56,838				83,153	56,838	35,332
Revenues	643				26,838					30,552	88,286	26,446
Depreciation and amortization	976				534					2,752	1,906	1,364
Capital expenditures	1,727				16,101					19,263	10,635	3,041
Eliminations
Segment Reporting Information [Line Items]
Assets		$ 0				$ (4,319)				0	(4,319)	(249)
Revenues	$ 0				$ (3,321)					$ (2,930)	$ (10,125)	$ (6,929)

SEGMENT INFORMATION - Narrative

SEGMENT INFORMATION - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Equity Method Investments	$ 363,578		$ 309,728	$ 649,250
Capital expenditures	18,583	$ 60,848	182,291	200,586	$ 124,215
Corporate
Segment Reporting Information [Line Items]
Capital expenditures		300	1,600	3,300
Corporate and Other
Segment Reporting Information [Line Items]
Capital expenditures	1,727	16,101	19,263	10,635	3,041
Corporate and Other \| Double E
Segment Reporting Information [Line Items]
Equity Method Investments	92,300		34,700
Capital expenditures			34,700
Reportable Segments
Segment Reporting Information [Line Items]
Capital expenditures	16,856	44,747	163,028	189,951	121,174
Reportable Segments \| Barnett Shale
Segment Reporting Information [Line Items]
Sales tax reimbursement		1,100	1,100
Capital expenditures	$ 657	$ (118)	$ 184	$ 1,370	$ 569

SEGMENT INFORMATION - Concentra

SEGMENT INFORMATION - Concentration Risk (Details) - Sales Revenue, Net - Customer Concentration Risk	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Counterparty A - Piceance Basin
Segment Reporting Information [Line Items]
Concentration risk, percentage	11.00%		11.00%
Counterparty B - Williston Basin
Segment Reporting Information [Line Items]
Concentration risk, percentage			10.00%		13.00%
Counterparty C - Piceance Basin
Segment Reporting Information [Line Items]
Concentration risk, percentage				10.00%

SEGMENT INFORMATION - Adjusted

SEGMENT INFORMATION - Adjusted EBITDA by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 75,188	$ 78,775	$ 317,503	$ 331,890	$ 329,527
Utica Shale
Segment Reporting Information [Line Items]
Adjusted EBITDA	5,928	6,193	29,292	30,285	34,011
Ohio Gathering
Segment Reporting Information [Line Items]
Adjusted EBITDA	7,939	9,210	39,126	39,969	41,246
Williston Basin
Segment Reporting Information [Line Items]
Adjusted EBITDA	16,192	18,734	69,437	76,701	66,413
Piceance Basin
Segment Reporting Information [Line Items]
Adjusted EBITDA	23,557	25,999	98,765	111,042	111,113
DJ Basin
Segment Reporting Information [Line Items]
Adjusted EBITDA	5,911	2,673	18,668	7,558	6,624
Barnett Shale
Segment Reporting Information [Line Items]
Adjusted EBITDA	8,760	11,374	43,043	43,268	46,232
Marcellus Shale
Segment Reporting Information [Line Items]
Adjusted EBITDA	5,320	5,142	20,051	24,267	23,888
Permian Basin
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 1,581	$ (550)	$ (879)	$ (1,200)	$ 0

SEGMENT INFORMATION - Reconcili

SEGMENT INFORMATION - Reconciliation of Net Income (Loss) to Adjusted EBITDA (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Sep. 30, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting [Abstract]
Income (loss) before income taxes and income (loss) from equity method investees		$ 438	$ (39,582)	$ (54,644)	$ 45,575	$ (134,187)
Add:
Corporate and Other expense		12,077	16,650	44,808	45,131	40,803
Interest expense		23,828	22,742	91,966	82,830	88,701
Early extinguishment of debt				0	0	22,039
Depreciation and amortization		29,900	28,153	111,574	106,930	115,118
Proportional adjusted EBITDA for equity method investees		7,939	9,210	39,126	39,969	41,246
Adjustments related to MVC shortfall payments		(5,442)	(4,199)	3,476	(3,632)	(41,373)
Adjustments related to capital reimbursement activity		(211)	(715)	(2,156)	(427)	0
Unit-based and noncash compensation		2,723	2,526	8,171	8,328	7,951
Loss (gain) on asset sales, net		115	(961)	(1,536)	0	527
Long-lived asset impairment		3,821	44,951	60,507	7,186	188,702
Goodwill impairment	$ 16,200			16,211	0	0
Total of reportable segments' measures of profit		$ 75,188	$ 78,775	$ 317,503	$ 331,890	$ 329,527

SEGMENT INFORMATION - Schedule

SEGMENT INFORMATION - Schedule of Adjustments Related to Minimum Volume Commitments Shortfall Payments (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Adjustments related to MVC shortfall payments	$ (5,442)	$ (4,199)	$ 3,476	$ (3,632)	$ (41,373)
Net change in deferred revenue for MVC shortfall payments					(40,758)
Expected MVC shortfall adjustments					(615)
Total adjustments related to MVC shortfall payments					(41,373)
Williston Basin
Segment Reporting Information [Line Items]
Adjustments related to MVC shortfall payments	(5,665)	(5,549)	0	0
Net change in deferred revenue for MVC shortfall payments					(37,693)
Expected MVC shortfall adjustments					0
Total adjustments related to MVC shortfall payments					(37,693)
Piceance Basin
Segment Reporting Information [Line Items]
Adjustments related to MVC shortfall payments	$ 223	(103)	(103)	10
Net change in deferred revenue for MVC shortfall payments					(3,065)
Expected MVC shortfall adjustments					(3)
Total adjustments related to MVC shortfall payments					(3,068)
Barnett Shale
Segment Reporting Information [Line Items]
Adjustments related to MVC shortfall payments		$ 1,453	$ 3,579	$ (3,642)
Net change in deferred revenue for MVC shortfall payments					0
Expected MVC shortfall adjustments					(612)
Total adjustments related to MVC shortfall payments					$ (612)

PROPERTY, PLANT, AND EQUIPMEN_3

PROPERTY, PLANT, AND EQUIPMENT, NET - Schedule of Property, Plant, and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 2,335,719	$ 2,326,398	$ 2,352,312
Less accumulated depreciation	465,636	443,909	388,213
Property, plant and equipment, net	1,870,083	1,882,489	1,964,099
Gathering and processing systems and related equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,193,225	2,182,950	2,155,325
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	73,040	78,716	137,920
Land and line fill
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	10,440	10,137	11,748
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 59,014	$ 54,595	$ 47,319

PROPERTY, PLANT, AND EQUIPMEN_4

PROPERTY, PLANT, AND EQUIPMENT, NET - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Long-lived asset impairment	$ 3,821		$ 44,951	$ 60,507	$ 7,186	$ 188,702
Bison Midstream
Property, Plant and Equipment [Line Items]
Long-lived asset impairment					3,900	$ 101,900
Red Rock Gathering Company LLC
Property, Plant and Equipment [Line Items]
Long-lived asset impairment				14,200
Cash purchase price of disposals				12,000
Permian Basin
Property, Plant and Equipment [Line Items]
Long-lived asset impairment				726	761
Asset impairment charges		$ 700
DJ Basin
Property, Plant and Equipment [Line Items]
Long-lived asset impairment				34,913	$ 9
Asset impairment charges	$ 3,600		34,700
Barnett Shale
Property, Plant and Equipment [Line Items]
Long-lived asset impairment				$ 9,629
Asset impairment charges			$ 9,700

PROPERTY, PLANT, AND EQUIPMEN_5

PROPERTY, PLANT, AND EQUIPMENT, NET - Schedule of Long-Lived Asset Impairments (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Long-lived asset impairment	$ 3,821	$ 44,951	$ 60,507	$ 7,186	$ 188,702
Williston Basin
Property, Plant and Equipment [Line Items]
Long-lived asset impairment			10	3,972	101,961
Piceance Basin
Property, Plant and Equipment [Line Items]
Long-lived asset impairment			14,162	1,004	697
DJ Basin
Property, Plant and Equipment [Line Items]
Long-lived asset impairment			34,913	9
Barnett Shale
Property, Plant and Equipment [Line Items]
Long-lived asset impairment			9,629
Utica Shale
Property, Plant and Equipment [Line Items]
Long-lived asset impairment				1,440	$ 878
Permian Basin
Property, Plant and Equipment [Line Items]
Long-lived asset impairment			$ 726	$ 761

PROPERTY, PLANT, AND EQUIPMEN_6

PROPERTY, PLANT, AND EQUIPMENT, NET - Schedule of Depreciation Expense and Capitalized Interest (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 21,698	$ 19,820	$ 78,489	$ 74,674	$ 75,382
Capitalized interest	$ 491	$ 1,915	$ 6,974	$ 8,497	$ 2,579

AMORTIZING INTANGIBLE ASSETS -

AMORTIZING INTANGIBLE ASSETS - Intangible Assets and Liabilities Subject to Amortization (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 459,818	$ 459,818	$ 468,852
Finite-Lived Intangible Assets, Accumulated Amortization	(235,742)	(227,540)	(195,436)
Finite-Lived Intangible Assets, Net	224,076	232,278	273,416
Favorable gas gathering contracts
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	24,195	24,195	24,195
Finite-Lived Intangible Assets, Accumulated Amortization	(15,359)	(15,125)	(13,905)
Finite-Lived Intangible Assets, Net	8,836	9,070	10,290
Contract intangibles
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	278,448	278,448	278,448
Finite-Lived Intangible Assets, Accumulated Amortization	(175,973)	(169,549)	(143,962)
Finite-Lived Intangible Assets, Net	102,475	108,899	134,486
Rights-of-way
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	157,175	157,175	166,209
Finite-Lived Intangible Assets, Accumulated Amortization	(44,410)	(42,866)	(37,569)
Finite-Lived Intangible Assets, Net	$ 112,765	$ 114,309	$ 128,640

AMORTIZING INTANGIBLE ASSETS _2

AMORTIZING INTANGIBLE ASSETS - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Dec. 31, 2017	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Rights-of-way
Finite-Lived Intangible Assets [Line Items]
Impairment charge for intangible assets		$ 0.5	$ 0.6
Williston Basin \| Contract Intangible Assets and Rights-of-Way Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Impairment charge for intangible assets	$ 85.2
Permian Basin
Finite-Lived Intangible Assets [Line Items]
Impairment charge for intangible assets				$ 0.5

AMORTIZING INTANGIBLE ASSETS _3

AMORTIZING INTANGIBLE ASSETS - Recognized Amortization Expense in Other Revenues and Cost and Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Revenue \| Favorable gas gathering contracts
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ (234)	$ (389)	$ (1,220)	$ (1,555)	$ (1,555)
Costs And Expenses \| Contract intangibles
Finite-Lived Intangible Assets [Line Items]
Amortization expense	6,424	6,397	25,587	26,141	34,202
Costs And Expenses \| Rights-of-way
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 1,544	$ 1,547	$ 6,278	$ 6,448	$ 6,153

AMORTIZING INTANGIBLE ASSETS _4

AMORTIZING INTANGIBLE ASSETS - Estimated Aggregate Annual Amortization Expected to be Recognized (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
2020	$ 23,926	$ 31,901
2021	28,209	28,209
2022	25,142	25,142
2023	25,088	25,088
2024	$ 14,917	$ 14,917

GOODWILL - Narrative (Details)

GOODWILL - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
GOODWILL - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill		$ 0	$ 16,211
Goodwill impairment	$ 16,200	16,211	0	$ 0
Mountaineer Midstream
Goodwill [Line Items]
Goodwill			16,200
Goodwill impairment		$ 16,200	$ 0	$ 0

GOODWILL - Schedule of goodwill

GOODWILL - Schedule of goodwill (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Accumulated goodwill impairment	$ 319,261	$ 303,050	$ 303,050
Piceance Basin
Goodwill [Line Items]
Accumulated goodwill impairment	45,478	45,478	45,478
Williston Basin
Goodwill [Line Items]
Accumulated goodwill impairment	257,572	257,572	257,572
Marcellus Shale
Goodwill [Line Items]
Accumulated goodwill impairment	$ 16,211	$ 0	$ 0

EQUITY METHOD INVESTMENTS - Nar

EQUITY METHOD INVESTMENTS - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		11 Months Ended				12 Months Ended
	Dec. 31, 2014	Mar. 31, 2020	Mar. 31, 2019	Nov. 30, 2019	[1]	Nov. 30, 2018	[1]	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 26, 2019
Schedule of Equity Method Investments [Line Items]
Contribution from General Partner								$ 23,643	$ 0	$ 0
Additional cash investments		$ 58,000						18,300
Impairment loss		3,311	$ (441)					$ (337,851)	$ (10,888)	$ (2,223)
Double E
Schedule of Equity Method Investments [Line Items]
Parental Maximum Guaranty For Capital Calls Not Met By Summit Permian Transmission											$ 350,000
Remaining capital contributions		251,000
Percentage of ownership interest								30.00%
Contribution from General Partner		350,000
Cash distribution to partnership		7,300
Net Assets		$ 92,300
Double E \| Principal Owner [Member]
Schedule of Equity Method Investments [Line Items]
Guarantor Obligations, Maximum Exposure								$ 308,900			$ 350,000
Percentage of ownership interest		70.00%
Contribution from General Partner		$ 23,600						$ 7,300
Double E \| JV Partner
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest		30.00%						70.00%
Cash distribution to partnership		$ 7,300						$ 7,300
OGC
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest	40.00%
Equity method potential ownership interest	40.00%
Non-affiliated owners' interest percent	60.00%
OGC \| Summit Midstream Partners, LLC
Schedule of Equity Method Investments [Line Items]
Net Assets								34,700
Equity method potential ownership interest									40.00%
Cost method ownership interest	$ 190,000
Cost method ownership interest	1.00%
Option value	$ 7,500
Impairment loss				$ (232,521)		$ (5,652)		$ 329,700	$ 7,700
Weighted Average Discount Rate Percent1								9.00%
OGC \| Summit Midstream Partners, LLC \| Long Lived Assets
Schedule of Equity Method Investments [Line Items]
Impairment loss								$ 6,300
OGC \| Principal Owner [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest		38.50%						38.50%	40.00%
OGC \| JV Partner
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest								38.50%	40.00%

[1]	Amount is comprised of (i) a $329.7 million impairment of our equity method investment in Ohio Gathering; (ii) the write-off of our basis difference of ($103.5) million in Ohio Gathering as a result of the impairment in our equity method investment in Ohio Gathering; and (iii) a $6.3 million impairment of long-lived assets in OCC.

EQUITY METHOD INVESTMENTS - Rol

EQUITY METHOD INVESTMENTS - Rollforward of the Investment in Equity Method Investees (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		11 Months Ended				12 Months Ended
	Mar. 31, 2020	Mar. 31, 2020	Mar. 31, 2019	Nov. 30, 2019		Nov. 30, 2018		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity Method Investment Roll Forward
Investment in Ohio Gathering, Begining Balance		$ 309,728	$ 649,250	$ 649,250				$ 649,250
Cash distributions		7,494	8,583					37,300	$ 35,271	$ 40,220
Impairment loss		(3,311)	441					337,851	10,888	2,223
Investment in Ohio,Ending Balance	$ 363,578	363,578						309,728	649,250
OGC \| Summit Midstream Partners, LLC
Equity Method Investment Roll Forward
Investment in Ohio Gathering, Begining Balance	271,268		$ 275,000	275,000		$ 649,250		275,000	649,250
Cash distributions	1,875			2,700		2,736
Impairment loss				232,521	[1]	5,652	[1]	$ (329,700)	(7,700)
Loss contingency				0		2,040
Basis difference	223,151			0		(116,832)
Investment in Ohio,Ending Balance	$ 496,294	$ 496,294		$ 510,221		$ 542,846			$ 275,000	$ 649,250

[1]	Amount is comprised of (i) a $329.7 million impairment of our equity method investment in Ohio Gathering; (ii) the write-off of our basis difference of ($103.5) million in Ohio Gathering as a result of the impairment in our equity method investment in Ohio Gathering; and (iii) a $6.3 million impairment of long-lived assets in OCC.

EQUITY METHOD INVESTMENTS - R_2

EQUITY METHOD INVESTMENTS - Rollforward of the Investment in Equity Method Investees Parenthetical (Details) - USD ($) $ in Thousands	3 Months Ended		11 Months Ended				12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Nov. 30, 2019	[1]	Nov. 30, 2018	[1]	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Impairment loss	$ 3,311	$ (441)					$ (337,851)	$ (10,888)	$ (2,223)
OGC \| Summit Midstream Partners, LLC
Schedule of Equity Method Investments [Line Items]
Impairment loss			$ (232,521)		$ (5,652)		329,700	$ 7,700
Write-off basis difference							103,500
OCC \| Summit Midstream Partners, LLC
Schedule of Equity Method Investments [Line Items]
Impairment loss							$ 6,300

[1]	Amount is comprised of (i) a $329.7 million impairment of our equity method investment in Ohio Gathering; (ii) the write-off of our basis difference of ($103.5) million in Ohio Gathering as a result of the impairment in our equity method investment in Ohio Gathering; and (iii) a $6.3 million impairment of long-lived assets in OCC.

EQUITY METHOD INVESTMENTS - Bal

EQUITY METHOD INVESTMENTS - Balance Sheet Information (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Nov. 30, 2019	Dec. 31, 2018	Nov. 30, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Current assets	$ 160,800	$ 139,861		$ 118,497
Total assets	2,626,297	2,574,098		3,033,219		$ 2,907,719
Current liabilities	85,429	89,547		129,757
Total liabilities	$ 1,780,201	$ 1,761,412		$ 1,641,652
Equity Method Investment, Nonconsolidated Investee, Other \| OGC
Schedule of Equity Method Investments [Line Items]
Current assets			$ 41,972		$ 37,403
Noncurrent assets			1,281,171		1,262,253
Total assets			1,323,143		1,299,656
Current liabilities			21,798		19,903
Noncurrent liabilities			4,113		3,688
Total liabilities			25,911		23,591
Equity Method Investment, Nonconsolidated Investee, Other \| OCC
Schedule of Equity Method Investments [Line Items]
Current assets			2,187		3,716
Noncurrent assets			28,323		27,203
Total assets			30,510		30,919
Current liabilities			4,016		3,912
Noncurrent liabilities			6,683		8,807
Total liabilities			$ 10,699		$ 12,719

EQUITY METHOD INVESTMENTS - Sta

EQUITY METHOD INVESTMENTS - Statements of Operations Information (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Mar. 31, 2020	Feb. 29, 2020	Mar. 31, 2019	Feb. 28, 2019	Dec. 31, 2019	Nov. 30, 2019	Dec. 31, 2018	Nov. 30, 2018	Dec. 31, 2017	Nov. 30, 2017
Schedule of Equity Method Investments [Line Items]
Net income (loss)	$ 3,762		$ (40,280)		$ (393,726)		$ 34,320		$ (136,914)
OGC
Schedule of Equity Method Investments [Line Items]
Total revenues		$ 30,068		$ 33,466		$ 142,138		$ 142,398		$ 140,679
Total operating expenses		25,750		25,487		108,234		136,722		111,897
Net income (loss)		4,311		7,972		33,897		5,670		28,785
OCC
Schedule of Equity Method Investments [Line Items]
Total revenues		2,727		2,266		8,601		10,177		8,607
Total operating expenses		30,855		2,973		38,815		9,053		8,298
Net income (loss)		$ (28,128)		$ (707)		$ (30,214)		$ 498		$ (907)

DEFERRED REVENUE - Rollforward

DEFERRED REVENUE - Rollforward of deferred revenue (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Movement in Deferred Revenue [Roll Forward]
Current deferred revenue, beginning balance	$ 13,493	$ 11,467	$ 10,088
Current deferred revenue, Additions	4,560	25,326	26,407
Current deferred revenue, Less revenue recognized	3,735	23,300	25,028
Current deferred revenue, ending balance	14,318	13,493	11,467
Noncurrent deferred revenue, beginning balance	38,709	39,504	35,528
Noncurrent deferred revenue, Additions	8,896	15,093	16,502
Noncurrent deferred revenue, Less reclassification to current deferred revenue	4,560	15,888	12,526
Noncurrent deferred revenue, ending balance	43,045	38,709	39,504
Utica Shale
Movement in Deferred Revenue [Roll Forward]
Current deferred revenue, beginning balance	18	18	18
Current deferred revenue, Additions	2	18	18
Current deferred revenue, Less revenue recognized	5	18	18
Current deferred revenue, ending balance	15	18	18
Noncurrent deferred revenue, beginning balance	3	21	39
Noncurrent deferred revenue, Additions	425	0	0
Noncurrent deferred revenue, Less reclassification to current deferred revenue	2	18	18
Noncurrent deferred revenue, ending balance	426	3	21
Williston Basin
Movement in Deferred Revenue [Roll Forward]
Current deferred revenue, beginning balance	1,933	1,414	1,017
Current deferred revenue, Additions	483	2,262	1,744
Current deferred revenue, Less revenue recognized	483	1,743	1,347
Current deferred revenue, ending balance	1,933	1,933	1,414
Noncurrent deferred revenue, beginning balance	3,634	4,393	4,215
Noncurrent deferred revenue, Additions	3,522	1,940	1,851
Noncurrent deferred revenue, Less reclassification to current deferred revenue	483	2,699	1,673
Noncurrent deferred revenue, ending balance	6,673	3,634	4,393
DJ Basin
Movement in Deferred Revenue [Roll Forward]
Current deferred revenue, beginning balance	2,860	739	358
Current deferred revenue, Additions	2,123	5,165	943
Current deferred revenue, Less revenue recognized	1,285	3,044	562
Current deferred revenue, ending balance	3,698	2,860	739
Noncurrent deferred revenue, beginning balance	7,589	7,284	4,505
Noncurrent deferred revenue, Additions	3,263	5,470	3,720
Noncurrent deferred revenue, Less reclassification to current deferred revenue	2,123	5,165	941
Noncurrent deferred revenue, ending balance	8,729	7,589	7,284
Piceance Basin
Movement in Deferred Revenue [Roll Forward]
Current deferred revenue, beginning balance	7,014	7,616	7,038
Current deferred revenue, Additions	1,547	16,211	21,955
Current deferred revenue, Less revenue recognized	1,544	16,813	21,377
Current deferred revenue, ending balance	7,017	7,014	7,616
Noncurrent deferred revenue, beginning balance	17,710	17,942	18,219
Noncurrent deferred revenue, Additions	1,304	6,104	7,869
Noncurrent deferred revenue, Less reclassification to current deferred revenue	1,547	6,336	8,146
Noncurrent deferred revenue, ending balance	17,467	17,710	17,942
Barnett Shale
Movement in Deferred Revenue [Roll Forward]
Current deferred revenue, beginning balance	1,630	1,642	1,619
Current deferred revenue, Additions	396	1,632	1,651
Current deferred revenue, Less revenue recognized	409	1,644	1,628
Current deferred revenue, ending balance	1,617	1,630	1,642
Noncurrent deferred revenue, beginning balance	9,575	9,628	8,217
Noncurrent deferred revenue, Additions	382	1,579	3,062
Noncurrent deferred revenue, Less reclassification to current deferred revenue	396	1,632	1,651
Noncurrent deferred revenue, ending balance	9,561	9,575	9,628
Marcellus Shale
Movement in Deferred Revenue [Roll Forward]
Current deferred revenue, beginning balance	38	38	38
Current deferred revenue, Additions	9	38	96
Current deferred revenue, Less revenue recognized	9	38	96
Current deferred revenue, ending balance	38	38	38
Noncurrent deferred revenue, beginning balance	198	236	333
Noncurrent deferred revenue, Additions	0	0	0
Noncurrent deferred revenue, Less reclassification to current deferred revenue	9	38	97
Noncurrent deferred revenue, ending balance	$ 189	$ 198	$ 236

DEBT - Components of Long-Term

DEBT - Components of Long-Term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Line of Credit Facility [Line Items]
Total debt		$ 1,638,500
Less current portion	$ 7,800	5,546	$ 14,500
Total long-term debt	1,641,065	1,622,279	1,464,280
SMP Summit Midstream Partners Holdings L L C
Line of Credit Facility [Line Items]
Total debt	1,648,865	1,627,825	1,478,780
SMP Summit Midstream Partners Holdings L L C \| Senior Notes Due May 2022
Line of Credit Facility [Line Items]
Revolving credit facility	160,750	161,500	226,750
Less unamortized debt issuance costs	(3,601)	(3,974)	(5,701)
SMP Holdings \| Senior Notes Due May 2022
Line of Credit Facility [Line Items]
Revolving credit facility	698,000	677,000	466,000
SMP Holdings \| Senior Notes Due August 2022
Line of Credit Facility [Line Items]
Unsecured notes	300,000	300,000	300,000
Less unamortized debt issuance costs	(1,521)	(1,686)	(2,362)
SMP Holdings \| Senior Notes Due April 2025
Line of Credit Facility [Line Items]
Unsecured notes	500,000	500,000	500,000
Less unamortized debt issuance costs	$ (4,763)	$ (5,015)	$ (5,907)

DEBT - Components of Long-Ter_2

DEBT - Components of Long-Term Debt (Parenthetical) (Details)	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Line of Credit Facility [Line Items]
Stated interest rate	7.00%
Senior Notes Due May 2022
Line of Credit Facility [Line Items]
Variable interest rate		7.80%	8.52%
SMP Summit Midstream Partners Holdings L L C \| Senior Notes Due May 2022
Line of Credit Facility [Line Items]
Stated interest rate	7.00%	7.80%
SMP Holdings \| Senior Notes Due May 2022
Line of Credit Facility [Line Items]
Variable interest rate	3.74%	4.55%	5.03%
SMP Holdings \| Senior Notes Due August 2022
Line of Credit Facility [Line Items]
Stated interest rate	5.50%	5.50%	5.50%
SMP Holdings \| Senior Notes Due April 2025
Line of Credit Facility [Line Items]
Stated interest rate	5.75%	5.75%	5.75%

DEBT - Maturities (Details)

DEBT - Maturities (Details) $ in Thousands	Dec. 31, 2019USD ($)
Debt
2020	$ 0
2021	0
2022	1,138,500
2023	0
2024	0
Thereafter	500,000
Total long-term debt	$ 1,638,500

DEBT - Revolving Credit Facilit

DEBT - Revolving Credit Facility (Narrative) (Details)	1 Months Ended	3 Months Ended	12 Months Ended
DEBT - Revolving Credit Facility (Narrative) (Details)	May 31, 2017USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	May 31, 2022USD ($)	Jun. 30, 2019USD ($)	May 26, 2017	May 25, 2017
Line of Credit Facility [Line Items]
Applicable margin			2.75%
Commitment fee on unused portion of the facility			0.50%
Line of credit facility, outstanding amount					$ 9,100,000
Revolving credit facility
Line of Credit Facility [Line Items]
Current borrowing capacity		$ 120,000,000
Borrowing capacity	$ 1,250,000	$ 1,250,000,000	$ 100,000,000	$ 1,250,000,000
Revolving credit facility maturity date	2022-05	2022-05
Accordion feature	$ 250,000,000	$ 250,000,000	$ 250,000,000
Leverage ratio							5
Senior secured leverage ratio	3.75
Commitment fee on unused portion of the facility		0.50%
Interest rate at period end		3.74%	4.55%
Unused portion under the facility		$ 542,900,000	$ 563,900,000
Line of credit facility, outstanding amount		9,100,000	9,100,000
Cumulative payment obligations, maximum			50,000,000
Debt issuance costs		5,500,000	6,200,000
Debt defaults		$ 0	$ 0
Revolving credit facility \| LIBOR
Line of Credit Facility [Line Items]
Applicable margin		2.75%
Revolving credit facility \| Minimum
Line of Credit Facility [Line Items]
Commitment fee on unused portion of the facility		0.30%	0.30%
Ratio of consolidated trailing 12-month EBITDA to net interest expense			1
Ratio of total net indebtedness to consolidated trailing 12-month EBITDA			1
Ratio of first lien net indebtedness to consolidated trailing 12-month EBITDA			1
Revolving credit facility \| Minimum \| ABR
Line of Credit Facility [Line Items]
Applicable margin		0.75%	0.75%
Revolving credit facility \| Minimum \| LIBOR
Line of Credit Facility [Line Items]
Applicable margin		1.75%	1.75%
Revolving credit facility \| Maximum
Line of Credit Facility [Line Items]
Leverage ratio						5.50
Commitment fee on unused portion of the facility		0.50%	0.50%
Ratio of consolidated trailing 12-month EBITDA to net interest expense			2.5
Ratio of total net indebtedness to consolidated trailing 12-month EBITDA			5.50
Ratio of first lien net indebtedness to consolidated trailing 12-month EBITDA			3.75
Revolving credit facility \| Maximum \| ABR
Line of Credit Facility [Line Items]
Applicable margin		1.75%	1.75%
Revolving credit facility \| Maximum \| LIBOR
Line of Credit Facility [Line Items]
Applicable margin		2.75%	2.75%

DEBT - Senior Notes (Narrative)

DEBT - Senior Notes (Narrative) (Details) - USD ($)	1 Months Ended
DEBT - Senior Notes (Narrative) (Details) - USD ($)	Nov. 30, 2018	Feb. 28, 2017	Jul. 31, 2014	Mar. 31, 2020	Dec. 31, 2019	Feb. 08, 2017
Debt Instrument [Line Items]
Stated interest rate				7.00%
Revolving credit facility
Debt Instrument [Line Items]
Extinguishment of debt		$ 172,000,000
Guarantor Subsidiaries
Debt Instrument [Line Items]
Cumulative percentage ownership in subsidiary	100.00%
5.75% Senior Notes
Debt Instrument [Line Items]
Debt face amount		$ 500,000,000
Stated interest rate		5.75%	5.75%
Maturity date		Apr. 15, 2025
Unsecured notes		$ 500,000,000
Default period		30 days
Compliance notice period		30 days
Final judgment		$ 75,000,000
Percent of principal (at least)		25.00%
Debt issuance costs						$ 7,700,000
5.75% Senior Notes \| Redemption period one
Debt Instrument [Line Items]
Percent of principal redeemed		35.00%
Redemption price, expressed as percentage of principal amount		105.75%
5.75% Senior Notes \| Redemption period two
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount		104.313%
5.75% Senior Notes \| Redemption period three
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount		100.00%
5.5% Senior Notes
Debt Instrument [Line Items]
Stated interest rate					5.50%
Debt issuance costs			$ 5,100,000
Events of default, period of payment default			30 days
Events of default, failure to comply with covenants, period after notice			180 days
Events of default, failure to comply with other agreements in the indenture, period after notice			30 days
Events of default, failure to pay final judgments, in excess of 20.0 million			$ 20,000,000
Declaration of immediate payment, holding percent of principal amount required			25.00%
Summit Holdings and Finance Corporation \| Senior Notes Due August 2022
Debt Instrument [Line Items]
Senior unsecured notes			$ 300,000,000
Stated interest rate			5.50%
Maturity date			Aug. 15, 2022
Summit Holdings and Finance Corporation \| 7.5% Senior Notes
Debt Instrument [Line Items]
Unsecured notes		$ 300,000,000
Redemption and call premiums		$ 17,900,000
Summit Holdings and Finance Corporation \| 5.5% Senior Notes \| Redemption period one
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount			101.375%
Summit Holdings and Finance Corporation \| 5.5% Senior Notes \| Redemption period two
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount			100.00%
Subsidiary of Summit Investments \| Summit Midstream OpCo, LP
Debt Instrument [Line Items]
Ownership interest	1.00%
Finance Corp \| Summit Holdings
Debt Instrument [Line Items]
Cumulative percentage ownership in subsidiary			100.00%

DEBT - SMP Holdings Term Loan (

DEBT - SMP Holdings Term Loan (Narrative) (Details) $ in Millions	Mar. 21, 2017USD ($)	Dec. 31, 2017	Dec. 31, 2019USD ($)shares	Mar. 31, 2020USD ($)shares
Debt Instrument [Line Items]
Debt instrument variable interest rate spread			2.75%
Long term debt instrument interest rate at a point in time				7.00%
Senior Secured Term Loan B
Debt Instrument [Line Items]
Debt instrument face amount	$ 300
Long term debt maturity date	May 15, 2022
Summit Midstream Partners Holdings L L C \| Senior Secured Term Loan B
Debt Instrument [Line Items]
Debt instrument face amount	$ 300
Long term debt maturity date	May 15, 2022
Long term debt instrument interest rate at a point in time			7.80%
Debt instrument operating cash flow ratio to be maintained		2
SMLP common units pledged as collateral under the SMPH Term Loan \| shares			34.6	34,600,000
Excess cash flow to be paid			$ 2.5	$ 4.8
Debt issuance costs gross			$ 8.7
London Interbank Offered Rate (LIBOR) \| Senior Secured Term Loan B
Debt Instrument [Line Items]
Long term debt instrument interest rate at a point in time	6.00%			6.00%
London Interbank Offered Rate (LIBOR) \| Summit Midstream Partners Holdings L L C \| Senior Secured Term Loan B
Debt Instrument [Line Items]
Debt instrument variable interest rate spread	6.00%		6.00%
ABR \| Senior Secured Term Loan B
Debt Instrument [Line Items]
Long term debt instrument interest rate at a point in time	5.00%
ABR \| Summit Midstream Partners Holdings L L C \| Senior Secured Term Loan B
Debt Instrument [Line Items]
Debt instrument variable interest rate spread	5.00%

FINANCIAL INSTRUMENTS - Concent

FINANCIAL INSTRUMENTS - Concentration Risk - Narrative (Details) - Customer	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CONCENTRATIONS OF RISK
Number of top customers	5	5
Five Largest Customers \| Accounts receivable \| Customer Concentration Risk
CONCENTRATIONS OF RISK
Concentration risk, percentage	49.00%	46.00%	39.00%

FINANCIAL INSTRUMENTS - Fair va

FINANCIAL INSTRUMENTS - Fair value of Debt Instruments (Details) - Summit Holdings - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Carrying value \| 5.5% Senior Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	$ 298,479	$ 298,314	$ 297,638
Carrying value \| 5.75% Senior Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	495,237	494,985	494,093
Fair Value \| 5.5% Senior Notes \| Estimated fair value (Level 2)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	58,875	266,750	286,625
Fair Value \| 5.75% Senior Notes \| Estimated fair value (Level 2)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	$ 53,125	$ 382,708	$ 455,208

FINANCIAL INSTRUMENTS - Fair _2

FINANCIAL INSTRUMENTS - Fair value of Debt Instruments (Parenthetical) (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Stated interest rate	7.00%
Summit Holdings \| 5.5% Senior Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Stated interest rate	5.50%	5.50%	5.50%
Debt face amount	$ 300,000,000	$ 300,000,000	$ 300,000,000
Summit Holdings \| 5.75% Senior Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Stated interest rate	5.75%	5.75%	5.75%
Debt face amount	$ 500,000,000	$ 500,000,000	$ 500,000,000

PARTNERS' CAPITAL AND MEZZANI_3

PARTNERS' CAPITAL AND MEZZANINE CAPITAL - Narrative (Details) $ / shares in Units, $ in Thousands	Jan. 29, 2020USD ($)$ / shares	Jan. 21, 2020	Mar. 31, 2019shares	Nov. 30, 2017USD ($)$ / shares	Feb. 28, 2017USD ($)Transactionshares	Mar. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019$ / sharesshares	Mar. 31, 2019USD ($)$ / sharesshares	Jun. 16, 2020USD ($)	Dec. 31, 2019USD ($)Transaction$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares	Jan. 16, 2020$ / sharesshares	Nov. 30, 2019shares
Partners Capital [Line Items]
Aggregate gross proceeds \| $										$ 0	$ 0	$ 17,078
Preferred units issued						300,000	300,000			300,000	300,000
Repayment of outstanding revolving credit facility \| $						$ 34,000		$ 101,000		$ 158,000	$ 84,000	$ 634,500
Maximum period following end of quarter to distribute all available cash										45 days
Per-unit annual distributions to unitholders (in dollars per unit) \| $ / shares	$ 0.125					$ 0.125		$ 0.575		$ 1.4375	$ 2.300	$ 2.300
Cash paid to unit holders \| $	$ 11,700
Cash distribution date	Feb. 14, 2020
Cash distribution date of record	Feb. 7, 2020
Revolving credit facility
Partners Capital [Line Items]
Repayment of outstanding revolving credit facility \| $				$ 293,200
Series A Preferred Units
Partners Capital [Line Items]
Preferred units issued												300,000		300,000
Interest in partnership per unit \| $ / shares				$ 1,000								$ 1,000
Distribution rate				9.50%						7.00%
Liquidation preference per unit \| $ / shares				$ 1,000			$ 1,000			$ 1,000
Distribution percentage of liquidation preference rate description										three-month LIBOR plus a spread of 7.43%
Proceeds from issuance of common limited partners units \| $										$ 27,400
Series A Preferred Units \| Paid-in-Kind Distributions
Partners Capital [Line Items]
Distribution percentage of subsidiary unit		7.00%
Distribution percentage of liquidation preference rate of undrawn commitment units		1.00%
Pro-rated issuance of preferred units						907	47
Pro-rated distribution of preferred units \| $ / shares						$ 13.9433	$ 1.5556
Pro-rated distribution of preferred units \| $						$ 70,000				$ 70,000
Pro-rated issuance of preferred units related to undrawn commitment						38
Series A Preferred Units \| Permian Holdco
Partners Capital [Line Items]
Preferred units issued						35,000	30,000			30,000			10,000
Interest in partnership per unit \| $ / shares						$ 1,000				$ 1,000
Series A preferred per unit, price \| $ / shares							$ 1,000			$ 1,000			$ 1,000
Series A Preferred Units \| Permian Holdco \| Double E
Partners Capital [Line Items]
Proceeds from issuance of common limited partners units \| $						$ 33,900			$ 9,700	$ 27,400
Series A Preferred Units \| LIBOR
Partners Capital [Line Items]
Distribution percentage of liquidation preference rate				7.43%
SMP Holdings
Partners Capital [Line Items]
Number of units of the partnership included for calculating earnings per unit						45,300,000				45,300,000
Common units
Partners Capital [Line Items]
Number of units of the partnership included for calculating earnings per unit						45,319,000		45,319		45,319,000	45,319,000	45,319,000
Limited Partner \| Public Offering \| 2016 SRS
Partners Capital [Line Items]
Units issued under ATM program (in shares)					4,000,000
Proceeds from Issuance of common stock \| $					$ 0
Common \| Public Offering
Partners Capital [Line Items]
Aggregate offering price \| $					$ 150,000
Transactions under ATM Program \| Transaction					0					0
Units issued in connection with offering												763,548
Aggregate gross proceeds \| $												$ 17,700
Compensation paid to sales agents \| $												$ 200
GP/IDR Exchange \| Summit Midstream Partners, LP \| SMP Holdings
Partners Capital [Line Items]
General partner units converted			8,750,000
GP/IDR Exchange \| Summit Midstream Partners, LP \| Common units \| SMP Holdings
Partners Capital [Line Items]
General partner units converted						8,750,000
GP/IDR Exchange \| Limited Partner \| Summit Midstream Partners, LP \| Common units \| SMP Holdings
Partners Capital [Line Items]
General partner units converted										10,714,285

PARTNERS' CAPITAL AND MEZZANI_4

PARTNERS' CAPITAL AND MEZZANINE CAPITAL - Cash Distributions Paid and Declared (Details) - $ / shares	Jan. 29, 2020	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Per-unit annual distributions to unitholders (in dollars per unit)	$ 0.125	$ 0.125	$ 0.575	$ 1.4375	$ 2.300	$ 2.300

EARNINGS PER UNIT (Details)

EARNINGS PER UNIT (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended									12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Net (loss) income attributable to limited partners	$ 5,643				$ (14,710)					$ (184,451)	$ 31,546	$ (183,411)
Phantom Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU	1,889,000				34,000					175,000	2,000	42,000
Limited Partner Interest Before Subordinated Units Converted To Common Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Net (loss) income attributable to limited partners	$ 5,643				$ (14,710)					$ (184,451)	$ 31,546	$ (183,411)
Common units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Net (loss) income attributable to limited partners	$ (2,427)	$ (180,504)	$ (7,914)	$ (2,756)	$ (21,835)	$ (29,061)	$ (23,225)	$ 42,448	$ 12,884	$ (213,009)	$ 3,046	$ (186,974)
Weighted-average common units outstanding – basic	45,319,000				45,319					45,319,000	45,319,000	45,319,000
Effect of nonvested phantom units										0	311,000	0
Weighted-average common units outstanding – diluted	45,319,000				45,319					45,319,000	45,630,000	45,319,000
Common unit – basic	$ (0.05)	$ (3.98)	$ (0.17)	$ (0.06)	$ (0.48)	$ (0.64)	$ (0.51)	$ 0.94	$ 0.28	$ (4.70)	$ 0.07	$ (4.13)
Common unit – diluted	$ (0.05)	$ (3.98)	$ (0.17)	$ (0.06)	$ (0.48)	$ (0.64)	$ (0.51)	$ 0.93	$ 0.28	$ (4.70)	$ 0.07	$ (4.13)
Series A Preferred Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Net (loss) income attributable to limited partners	$ 7,125	$ 7,125	$ 7,125	$ 7,125	$ 7,125	$ 7,125	$ 7,125	$ 7,125	$ 7,125	$ 28,500	$ 28,500	$ 3,563
Series A Preferred Units \| Subsidiary
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Net (loss) income attributable to limited partners	$ 945	$ 58			$ 0					$ 58	$ 0	$ 0

EARNINGS PER UNIT - Narrative (

EARNINGS PER UNIT - Narrative (Details) - SMP Holdings - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Number of units of the partnership included for calculating earnings per unit	45,300,000	45,300,000
Antidilutive units excluded from the computation of earnings per unit	$ 34.6	$ 34.6

UNIT-BASED AND NONCASH COMPEN_3

UNIT-BASED AND NONCASH COMPENSATION - Narrative (Details) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2020Director$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018$ / sharesshares	Dec. 31, 2017$ / sharesshares	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average remaining vesting period		1 year 7 months 6 days
Phantom Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
SMLP LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserved for issuance (in shares)		5,000,000
Units remaining available		1,300,000
Unrecognized unit-based compensation \| $		$ 8.5
SMLP LTIP \| Time Vesting And Distribution Targets
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangement percentage of membersip interest authorized for issuance					7.50%
Share based compensation by shae based payment arrangement percentage of available membership interest authorized for grant					6.355%
Percentage of net profit interests vested and outstanding		4.20%
Percentage of net profit interests nonvested share based payment arrangement		0.00%	0.00%
Vesting period					5 years
SMLP LTIP \| Phantom Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserved for issuance (in shares)	15,000,000
Units remaining available	6,900,000
Vesting period	3 years
Granted units (in shares)	3,811,301	1,913,099	515,358	371,972
Grant date fair value (in dollars per share) \| $ / shares	$ 0.55	$ 6.48	$ 15.25	$ 22.50
Issued units (in shares)	549,450
Units vested (in shares)	418,999	602,617	359,016	293,222
No. of directors \| Director	3
Common units extended term	10 years

UNIT-BASED AND NONCASH COMPEN_4

UNIT-BASED AND NONCASH COMPENSATION - SMLP Long-Term Incentive Plan (Details) - SMLP LTIP - Phantom Units - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Units
Nonvested units(in shares)	2,105,995	864,124	749,274	691,955
Units granted (in shares)	3,811,301	1,913,099	515,358	371,972
Unit vested (in shares)	(418,999)	(602,617)	(359,016)	(293,222)
Units forfeited (in shares)		(68,611)	(41,492)	(21,431)
Nonvested units(in shares)		2,105,995	864,124	749,274
Weighted-average grant date fair value
Nonvested, Weighted-average grant date fair value, beginning (in dollars per unit)	$ 7.69	$ 17.11	$ 20.07	$ 19.59
Units granted, Weighted-average grant date fair value (in dollars per unit)	$ 0.55	6.48	15.25	22.50
Units vested, Weighted-average grant date fair value (in dollars per unit)		16.78	22.39	24.76
Units forfeited, Weighted-average grant date fair value (in dollars per unit)		12.87	17.27	20.07
Nonvested, Weighted-average grant date fair value, beginning (in dollars per unit)		$ 7.69	$ 17.11	$ 20.07

UNIT-BASED AND NONCASH COMPEN_5

UNIT-BASED AND NONCASH COMPENSATION - Schedule of Intrinsic Values (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SMLP LTIP \| Phantom Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of vested LTIP awards	$ 5,940	$ 5,393	$ 6,657

UNIT-BASED AND NONCASH COMPEN_6

UNIT-BASED AND NONCASH COMPENSATION - SMP Net Profits Interests (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
SMLP LTIP unit-based compensation	$ 2,723	$ 2,526	$ 8,171	$ 8,088	$ 7,878
SMLP LTIP \| General and administrative expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
SMLP LTIP unit-based compensation			$ 8,171	$ 8,328	$ 7,951

LEASES, COMMITMENTS AND CONTI_3

LEASES, COMMITMENTS AND CONTINGENCIES - Narrative (Details)	1 Months Ended	3 Months Ended		12 Months Ended
LEASES, COMMITMENTS AND CONTINGENCIES - Narrative (Details)	Mar. 31, 2019USD ($)MMcf	Mar. 31, 2020USD ($)Agreement	Jun. 30, 2019USD ($)	Dec. 31, 2019USD ($)	Nov. 30, 2019USD ($)
Loss Contingencies [Line Items]
Finance leases, term of contract		3 years		3 years
Lease agreements renewal periods					5 years
Lessee, operating lease, existence of residual value guarantee [true false]		false		false
Lessee, operating lease, residual value guarantee, Description		Our leases do not contain residual value guarantees.		Our leases do not contain residual value guarantees.
Lessee, operating lease, assumptions and judgments, whether contract is or contains lease		Our significant assumptions or judgments include the determination of whether a contract contains a lease and the discount rate used in our lease liabilities.		Our significant assumptions or judgments include the determination of whether a contract contains a lease and the discount rate used in our lease liabilities.
Lessee, operating lease, assumptions and judgments, discount rate, description		The rate implicit in our lease contracts is not readily determinable. In determining the discount rate used in our lease liabilities, we analyzed certain factors in our incremental borrowing rate, including collateral assumptions and the term used. Our incremental borrowing rate on the Revolving Credit Facility was 4.55% at December 31, 2019, which reflects the fixed rate at which we could borrow a similar amount, for a similar term and with similar collateral as in the lease contracts at the commencement date.		The rate implicit in our lease contracts is not readily determinable. In determining the discount rate used in our lease liabilities, we analyzed certain factors in our incremental borrowing rate, including collateral assumptions and the term used. Our incremental borrowing rate on the Revolving Credit Facility was 4.55% at December 31, 2019, which reflects the fixed rate at which we could borrow a similar amount, for a similar term and with similar collateral as in the lease contracts at the commencement date.
Electric power \| MMcf	60
Cost of project	$ 7,800,000
Up front payment included in property, plant and equipment	$ 3,000,000
Additional cost to increase transmission line capacity			$ 4,300,000
Letter of credit initial term			1 year
Irrevocable letter of credit payable			$ 9,100,000
Letter of credit renew term			12 months	12 months
Future minimum sublease payment					$ 1,200,000
Business Interruption
Loss Contingencies [Line Items]
Recoveries recognized				$ 2,600,000
Property Recoveries
Loss Contingencies [Line Items]
Recoveries recognized				400,000
Revolving credit facility
Loss Contingencies [Line Items]
Finance operating Lease obligations not exceed consolidated total assets		$ 50,000,000		$ 50,000,000
Percentage of operating lease incremental borrowing rate				4.55%
Irrevocable letter of credit payable		$ 9,100,000		$ 9,100,000
Office Space
Loss Contingencies [Line Items]
Lessee, operating lease, existence of option to extend [true false]		true		true
Lessee, operating lease, option to extend		We have options to extend the lease and sublease terms of certain office space in Texas, Colorado and West Virginia. The beginning of the noncancelable lease and sublease period for these agreements ranges from 2014 to 2020 and the lease and sublease period ends between 2020 and 2028. These lease and sublease agreements contain between one and three options to renew the lease and sublease for a period of between two and five years. As of March 31, 2020, the exercise of the renewal options for these agreements are not reasonably certain and, as a result, the payments associated with these renewals are not included in the measurement of the lease liability and right-of-use (“ROU”) asset		We have options to extend the lease term of certain office space in Texas, Colorado and West Virginia. The beginning of the noncancelable lease period for these leases ranged from 2014 to 2018 and the lease period ends between 2020 and 2028. These lease agreements contain between one and three options to renew the lease for a period of between two and five years. As of December 31, 2019, the exercise of the renewal options for these leases are not reasonably certain and, as a result, the payments associated with these renewals are not included in the measurement of the lease liability and ROU asset.
Equipment
Loss Contingencies [Line Items]
Lessee, operating lease, option to extend		We also have options to extend the lease term of certain compression equipment used at the Summit Utica gathering system. The beginning of the noncancelable lease period for these leases is 2017 and the lease period ends in 2020. In April 2020, we renewed the lease period for periods of one to three years. Our future minimum lease payments are approximately $2.3 million.		We also have options to extend the lease term of certain compression equipment used at the Summit Utica gathering system. The beginning of the noncancelable lease period for these leases was 2017 and the lease period ends in 2020. Upon expiration of the noncancelable lease period, we have the option to renew the leases on a month-to-month basis; we therefore have not included any amounts attributable to renewals in the measurement
Minimum \| Office Space
Loss Contingencies [Line Items]
Operating leases, term of contract		3 years		3 years
Operating lease, number of renewal terms \| Agreement		1
Lease agreements renewal periods		2 years		2 years
Minimum \| Equipment
Loss Contingencies [Line Items]
Operating leases, term of contract		3 years		3 years
Maximum \| Meadowlark Midstream Gathering System \| Principal Owner
Loss Contingencies [Line Items]
Coverage from pollution liability insurance policy		$ 25,000,000		$ 25,000,000
Coverage from property and business interruption insurance policy		$ 200,000,000		$ 200,000,000
Maximum \| Office Space
Loss Contingencies [Line Items]
Operating leases, term of contract		10 years		10 years
Operating lease, number of renewal terms \| Agreement		3
Lease agreements renewal periods		5 years		5 years
Maximum \| Equipment
Loss Contingencies [Line Items]
Operating leases, term of contract		4 years		4 years
Senior Secured Term Loan B
Loss Contingencies [Line Items]
Finance operating Lease obligations not exceed consolidated total assets		$ 5,000,000		$ 5,000,000

LEASES, COMMITMENTS AND CONTI_4

LEASES, COMMITMENTS AND CONTINGENCIES - Schedule of Right of Use Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Right-of-use asset	$ 4,306	$ 3,580
Finance	2,649	3,159
Total	6,955	6,739
Lease liabilities, current
Operating	967	1,221
Finance	1,023	1,246
Total	1,990	2,467
Lease liabilities, noncurrent
Operating	3,482	2,513
Finance	483	676
Total	$ 3,965	$ 3,189

LEASES, COMMITMENTS AND CONTI_5

LEASES, COMMITMENTS AND CONTINGENCIES - Schedule of Lease Cost and Other Information (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Lease cost
Amortization of ROU assets (included in depreciation and amortization)	$ 352	$ 368	$ 1,559
Interest on lease liabilities (included in interest expense)	18	23	102
Operating lease cost (included in general and administrative expense)	772	832	3,345
Total lease cost	1,142	1,223	5,006
Other information
Operating cash outflows from operating leases	708	821	3,396
Operating cash outflows from finance leases	18	23	102
Financing cash outflows from finance leases	417	445	1,873
ROU assets obtained in exchange for new operating lease liabilities	$ 1,199		1,218
ROU assets obtained in exchange for new finance lease liabilities		$ 693	$ 1,350
Weighted-average remaining lease term (years) - operating leases	6 years	3 years 6 months	5 years 9 months 18 days
Weighted-average remaining lease term (years) - finance leases	2 years	2 years	2 years
Weighted-average discount rate - operating leases	5.00%	5.00%	5.00%
Weighted-average discount rate - finance leases	4.00%	4.00%	4.00%

LEASES, COMMITMENTS AND CONTI_6

LEASES, COMMITMENTS AND CONTINGENCIES - Rent Expense (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Lease expense	$ 953	$ 990	$ 4,038	$ 4,108	$ 3,963

LEASES, COMMITMENTS AND CONTI_7

LEASES, COMMITMENTS AND CONTINGENCIES - Future Minimum Lease Payments Due and Future Minimum Rentals to be Received under Noncancelable Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Operating lease, Future minimum lease payments, 2020	$ 1,046	$ 1,705
Operating lease, Future minimum lease payments, 2021	1,125	1,004
Operating lease, Future minimum lease payments, 2022	883	551
Operating lease, Future minimum lease payments, 2023	741	408
Operating lease, Future minimum lease payments, 2024	555	240
Operating lease, Future minimum lease payments, 2025	464	153
Operating lease, Future minimum lease payments, Thereafter	742	742
Operating lease, Total future minimum lease payments	5,556	4,803
Finance lease, Future minimum lease payments, 2020	873	1,299
Finance lease, Future minimum lease payments, 2021	606	616
Finance lease, Future minimum lease payments, 2022	76	76
Finance lease, Total future minimum lease payments	$ 1,555	$ 1,991

LEASES, COMMITMENTS AND CONTI_8

LEASES, COMMITMENTS AND CONTINGENCIES - Schedule of Future Minimum Rental Payments for Operating Leases (Details) $ in Thousands	Dec. 31, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
2019	$ 3,133
2020	1,018
2021	550
2022	506
2023	373
Thereafter	621
Total future minimum lease payments	$ 6,201

LEASES, COMMITMENTS AND CONTI_9

LEASES, COMMITMENTS AND CONTINGENCIES - Schedule of Future Payments Due Under Finance Leases (Details) $ in Thousands	Dec. 31, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
2019	$ 1,473
2020	902
2021	174
Total finance lease obligations	2,549
Less: Amounts representing interest	(104)
Net present value of finance lease obligations	2,445
Less: Amount representing current portion (included in Other current liabilities)	(1,406)
Finance lease obligations, less current portion (included in Other noncurrent liabilities)	$ 1,039

LEASES, COMMITMENTS AND CONT_10

LEASES, COMMITMENTS AND CONTINGENCIES - Environmental Matters (Details) - Meadowlark Midstream Gathering System - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accrual for Environmental Loss Contingencies [Roll Forward]
Accrued environmental remediation, beginning balance	$ 4,651	$ 5,636	$ 5,344
Payments made	(17)	(2,284)	(3,808)
Additional accruals		1,299	4,100
Accrued environmental remediation, ending balance	$ 4,634	$ 4,651	$ 5,636

DISPOSITIONS, DROP DOWN TRANS_2

DISPOSITIONS, DROP DOWN TRANSACTIONS AND RESTRUCTURING - Red Rock Gathering Asset Disposition (Details) - USD ($) $ in Thousands	Dec. 02, 2019	Dec. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Proceeds from asset sale			$ 0	$ 89,461	$ 102,111	$ 496	$ 2,300
Long-lived asset impairment			$ 3,821	$ 44,951	$ 60,507	$ 7,186	$ 188,702
Red Rock Gathering Company LLC \| Disposal, not discontinued operations \| Purchase and Sale Agreement
Business Acquisition [Line Items]
Proceeds from asset sale		$ 12,000
Long-lived asset impairment	$ 14,200

DISPOSITIONS, DROP DOWN TRANS_3

DISPOSITIONS, DROP DOWN TRANSACTIONS AND RESTRUCTURING - Tioga Midstream Disposition (Details) - Tioga Midstream, LLC - Disposal, not discontinued operations - Purchase and Sale Agreement $ in Millions	Mar. 22, 2019USD ($)	Feb. 28, 2019USD ($)Agreement
Business Acquisition [Line Items]
Number of purchase and sale agreements \| Agreement		2
Cash purchase price of disposals		$ 90
Gain on sale of business	$ 0.9

DISPOSITIONS, DROP DOWN TRANS_4

DISPOSITIONS, DROP DOWN TRANSACTIONS AND RESTRUCTURING - Restructuring Activities (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Employee Related Costs
Business Acquisition [Line Items]
Restructuring and related cost, expected cost	$ 4.1	$ 6
Severance costs	1.9	3.8
Cash payment	2.1
Employee related cost included in current liabilities	2.4	2.7
Consultants
Business Acquisition [Line Items]
Restructuring costs	0.9	1.2
Restructuring and related cost, expected cost	0.2	0.2
Cash payment	1.1
Consultant related liabilities current	0.4	0.6
General and administrative expense
Business Acquisition [Line Items]
Restructuring costs	$ 2.8	$ 5

UNAUDITED QUARTERLY FINANCIAL_3

UNAUDITED QUARTERLY FINANCIAL DATA (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended									12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Limited Partners' Capital Account [Line Items]
Total revenues	$ 104,903	$ 112,247	$ 100,187	$ 99,686	$ 131,408	$ 133,671	$ 127,479	$ 128,183	$ 117,320	$ 443,528	$ 506,653	$ 488,741
Net (loss) income attributable to SMLP		(345,345)	(11,129)	3,028	(40,280)	(3,401)	14,353	11,861	11,507
Net (loss) income attributable to noncontrolling interest	(1,881)	(172,024)	(10,340)	(1,341)	(25,570)	18,535	30,453	(37,712)	(8,502)	(209,275)	2,774	46,497
Net (loss) income attributable to limited partners	5,643				(14,710)					(184,451)	31,546	(183,411)
Series A Preferred Units
Limited Partners' Capital Account [Line Items]
Net (loss) income attributable to limited partners	7,125	7,125	7,125	7,125	7,125	7,125	7,125	7,125	7,125	28,500	28,500	3,563
Series A Preferred Units \| Subsidiary
Limited Partners' Capital Account [Line Items]
Net (loss) income attributable to limited partners	945	58			0					58	0	0
Common units
Limited Partners' Capital Account [Line Items]
Net (loss) income attributable to limited partners	$ (2,427)	$ (180,504)	$ (7,914)	$ (2,756)	$ (21,835)	$ (29,061)	$ (23,225)	$ 42,448	$ 12,884	$ (213,009)	$ 3,046	$ (186,974)
Common unit – basic	$ (0.05)	$ (3.98)	$ (0.17)	$ (0.06)	$ (0.48)	$ (0.64)	$ (0.51)	$ 0.94	$ 0.28	$ (4.70)	$ 0.07	$ (4.13)
Common unit – diluted	$ (0.05)	$ (3.98)	$ (0.17)	$ (0.06)	$ (0.48)	$ (0.64)	$ (0.51)	$ 0.93	$ 0.28	$ (4.70)	$ 0.07	$ (4.13)

SUBSEQUENT EVENTS - Narrative (

SUBSEQUENT EVENTS - Narrative (Details) $ / shares in Units, $ in Millions	May 28, 2020USD ($)shares	Apr. 10, 2020d$ / shares	Mar. 31, 2020
Subsequent Event [Line Items]
Purchase agreement date	May 28, 2020
Closing price of common stock units \| $ / shares		$ 1
Number of consecutive days \| d		30
Notice period to cure the deficiency and regain compliance		6 months
Plan to reduction in capital expenditures and ongoing implementation of expense, percentage		30.00%
Stated interest rate			7.00%
Summit Investments
Subsequent Event [Line Items]
Payments to Acquire Businesses, Gross \| $	$ 35
Summit Investments \| Common units
Subsequent Event [Line Items]
Business acquisition, share issued (shares)	10,000,000
Summit Investments \| Common units one
Subsequent Event [Line Items]
Business acquisition, share issued (shares)	5,915,827
SMP Holdings
Subsequent Event [Line Items]
SMLP common units pledged as collateral under the SMPH Term Loan	34,604,581
SMLP common units not pledged as collateral under the SMPH Term Loan	10,714,285
Term Loan Credit Agreements
Subsequent Event [Line Items]
Borrowing capacity \| $	$ 35
Maturity date	Mar. 31, 2021
Stated interest rate	8.00%
Line of Credit Facility, Description	The Loans under the Term Loan Credit Agreements will bear interest at a rate of 8.00% per annum, and will generally be (i) guaranteed by the Partnership and each subsidiary of the Borrower that guarantees the obligations under the Borrower’s Revolving Credit Facility, and (ii) secured by a first priority lien on and security interest in all property that secures the obligations under the Revolving Credit Facility.