0001564590-20-051994 | 10-Q | XBRL Viewer | Summit Midstream Partners LP

$ 90,153

$ 100,187

$ 287,063

$ 331,281

Cost of natural gas and NGLs

8,632

7,472

22,945

50,802

Operation and maintenance

22,168

26,231

65,131

74,771

General and administrative

10,561

10,029

39,908

38,979

Depreciation and amortization

29,505

27,443

88,801

82,044

Transaction costs

726

129

1,944

2,562

Gain on asset sales, net

(104)

(347)

(270)

(1,595)

Long-lived asset impairment

4,475

45,021

Goodwill impairment

16,211

Total costs and expenses

71,488

87,168

222,934

308,795

Other income

795

644

304

Interest expense

(19,018)

(23,462)

(64,836)

(68,547)

Gain on early extinguishment of debt

24,690

78,925

Income (loss) before income taxes and equity method investment income (loss)

25,132

(10,431)

78,862

(45,757)

Income tax benefit (expense)

(298)

(21)

104

(1,427)

Income (loss) from equity method investees

795

(677)

7,146

(1,197)

Net income (loss) attributable to noncontrolling interest

25,629

(11,129)

86,112

(48,381)

(10,340)

(3,274)

(37,251)

25,629

(789)

89,386

(11,130)

54,945

Series A Preferred Units

6,481

7,125

20,731

21,375

Series A Preferred Units | Subsidiaries

54,945

7,298

9,640

Common Units

Net income (loss) per limited partner unit:

$ 66,795

$ (7,914)

$ 113,960

$ (32,505)

Basic (in dollars per share)

$ 1.29

$ (0.17)

$ 2.41

$ (0.72)

Diluted (in dollars per share)

$ 1.25

$ (0.17)

$ 2.34

$ (0.72)

Weighted-average limited partner units outstanding:

Basic (shares)

^[1]

51,974

45,319

47,331

45,319

Diluted (shares)

53,650

45,319

48,782

45,319

Natural Gas, Gathering, Transportation, Marketing and Processing

Revenues:

$ 71,964

$ 80,968

$ 229,667

$ 243,039

Oil and Condensate

Revenues:

Product and Service, Other

10,783

12,219

35,246

68,438

Revenues:

Beginning balance at Dec. 31, 2018

$ 7,406

$ 7,000

$ 22,150

$ 19,804

[1]	As a result of the GP Buy-In Transaction, our historical results are those of Summit Investments. The number of common units of 45.3 million as of September 30, 2019 represents those of Summit Investments and has been used for the earnings per unit calculations presented herein.

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF PARTNERS' CAPITAL - USD ($)
$ in Thousands

Total

Partners' Capital

Series A Preferred Units

Noncontrolling Interest

Series A Preferred Units

Noncontrolling Interest

Common Noncontrolling Interest

^[1]

$ 1,391,567

$ 543,479

$ 293,616

$ 554,472

(40,280)

(21,835)

7,125

(25,570)

(27,374)

2,526

Tax withholdings and associated payments on vested SMLP LTIP awards

(2,387)

2,387

(2,524)

Conversion of noncontrolling interest related to cancellation of subsidiary incentive distribution rights

48,203

(48,203)

Ending balance at Mar. 31, 2019

1,323,915

567,460

300,741

455,714

3,028

(2,756)

7,125

(1,341)

Net cash distributions to Energy Capital Partners

(28,076)

(14,250)

(13,826)

(68,984)

1,393

Tax withholdings and associated payments on vested SMLP LTIP awards

(40)

(93)

Ending balance at Jun. 30, 2019

1,231,183

495,680

293,616

441,887

(11,129)

(7,914)

7,125

(10,340)

(13,829)

1,451

Tax withholdings and associated payments on vested SMLP LTIP awards

(173)

173

Ending balance at Sep. 30, 2019

1,207,731

487,593

300,741

419,397

Beginning balance at Dec. 31, 2019

785,236

305,550

293,616

186,070

2,817

(2,427)

7,125

(1,881)

(6,037)

2,723

Tax withholdings and associated payments on vested SMLP LTIP awards

(2,322)

2,322

(984)

Ending balance at Mar. 31, 2020

783,755

300,801

300,741

182,213

Beginning balance at Dec. 31, 2019

785,236

305,550

293,616

186,070

Conversion of noncontrolling interest related to cancellation of subsidiary incentive distribution rights

54,945

Ending balance at Sep. 30, 2020

816,635

567,284

$ 249,351

Beginning balance at Mar. 31, 2020

783,755

300,801

300,741

182,213

55,324

49,592

2,375

4,750

(1,393)

Tax withholdings and associated payments on vested SMLP LTIP awards

1,846

515

1,331

(62)

(28)

(34)

GP Buy-In Transaction assumption of noncontrolling interest in SMLP

182,117

305,491

$ (305,491)

$ (182,117)

Repurchase of common units under GP Buy-In Transaction

(44,078)

Other

(61)

Ending balance at Jun. 30, 2020

796,724

488,858

307,866

18,331

11,850

6,481

Tax withholdings and associated payments on vested SMLP LTIP awards

1,622

(117)

Tax withholdings on Series A Preferred Unit Exchange

(237)

Conversion of Series A Preferred Units to SMLP common units inclusive of a $54.9 million deemed contribution to common unit holders (Note 10)

64,996

(64,996)

Other

312

Conversion of noncontrolling interest related to cancellation of subsidiary incentive distribution rights

54,945

Ending balance at Sep. 30, 2020

$ 816,635

$ 567,284

$ 249,351

[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 CONSOLIDATED STATEMENTS OF PARTNERS' CAPITAL (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
Statement Of Partners Capital [Abstract]
Deemed contribution on exchange of preferred units	$ 54,945	$ 54,945

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income (loss)	$ 86,112	$ (48,381)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	89,505	83,030
Noncash lease expense	1,925	2,299
Amortization of debt issuance costs	4,870	4,719
Unit-based and noncash compensation	6,191	5,370
(Income) loss from equity method investees	(7,146)	1,197
Distributions from equity method investees	19,859	28,008
Gain on asset sales, net	(270)	(1,595)
Gain on early extinguishment of debt	(78,925)	0
Gain on fair value of warrants	(838)	0
Long-lived asset impairment	4,475	45,021
Goodwill impairment	0	16,211
Changes in operating assets and liabilities:
Accounts receivable	20,922	8,363
Trade accounts payable	470	820
Accrued expenses	(1,078)	(11,965)
Deferred revenue, net	7,379	1,910
Ad valorem taxes payable	(1,546)	(2,061)
Accrued interest	2,680	3,065
Accrued environmental remediation, net	(1,368)	(2,025)
Other, net	(6,410)	(6,369)
Net cash provided by operating activities	146,807	127,617
Cash flows from investing activities:
Capital expenditures	(35,312)	(151,663)
Proceeds from asset sale (net of cash of $1,475 for the period ended September 30, 2019)	0	90,111
Distribution from equity method investment	0	7,252
Investment in equity method investee	(92,072)	(11,330)
Other, net	2,486	343
Net cash used in investing activities	(124,898)	(65,287)
Cash flows from financing activities:
Net cash distributions to noncontrolling interest SMLP unitholders	(6,037)	(55,029)
Series A Preferred Unit distributions	0	(14,250)
Net cash distributions to Energy Capital Partners	0	(68,984)
Borrowings under Revolving Credit Facility	165,500	265,000
Repayments on Revolving Credit Facility	(34,000)	(131,000)
Repayments on SMPH Term Loan	(6,300)	(59,500)
Proceeds from issuance of Subsidiary Series A preferred units, net of issuance costs	48,710	0
Borrowings under ECP Loans (Note 8)	35,000	0
Repayment of ECP Loans (Note 8)	(35,000)	0
Purchase of common units in GP Buy-In Transaction	(41,778)	0
Debt issuance costs	(835)	(584)
Proceeds from asset sale	288	0
Other, net	(2,527)	(3,930)
Net cash provided by (used in) financing activities	(8,535)	(68,277)
Net change in cash, cash equivalents and restricted cash	13,374	(5,947)
Cash, cash equivalents and restricted cash, beginning of period	36,922	16,173
Cash, cash equivalents and restricted cash, end of period	50,296	10,226
Open Market Repurchases
Cash flows from financing activities:
Repurchases of 2022 and 2025 Senior Notes (Note 8)	(82,844)	0
Tender Offers
Cash flows from financing activities:
Repurchases of 2022 and 2025 Senior Notes (Note 8)	$ (48,712)	$ 0

ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION

9 Months Ended

Sep. 30, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION

1. ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION

Organization. SMLP, a Delaware limited partnership, was formed in May 2012 and began operations in October 2012. SMLP is a value-oriented limited partnership focused on developing, owning and operating midstream energy infrastructure assets that are strategically located in unconventional resource basins, primarily shale formations, in the continental United States. Our business activities are conducted through various operating subsidiaries, each of which is owned or controlled by our wholly owned subsidiary holding company, Summit Holdings, a Delaware limited liability company. References to the "Partnership," "we," or "our" refer collectively to SMLP and its subsidiaries.

On May 28, 2020, the Partnership closed the transactions contemplated by the Purchase Agreement (the “Purchase Agreement”), dated May 3, 2020, with affiliates of its then private equity sponsor, Energy Capital Partners II, LLC (“ECP”), to acquire Summit Midstream Partners, LLC (“Summit Investments”). The purchase of Summit Investments resulted in the Partnership acquiring an indirect ownership interest in Summit Midstream Partners Holdings, LLC, a Delaware limited liability company (“SMP Holdings”), which in turn owned (a) 34,604,581 SMLP common units representing limited partner interests in the Partnership (the “common units”) that were pledged as collateral under the SMPH Term Loan, (b) 10,714,285 SMLP common units that were not pledged as collateral under the SMPH Term Loan and (c) a deferred purchase price obligation receivable owed by the Partnership. In addition, the Partnership acquired 5,915,827 SMLP common units held by an affiliate of ECP. The total purchase price was $35.0 million in cash and warrants to purchase up to 10 million SMLP common units (refer to Note 11 – Partners’ Capital and Mezzanine Capital for additional details). Pursuant to the Purchase Agreement, the Partnership, through its indirect ownership interest of SMP Holdings, will retain any liabilities stemming from the release of produced water from a produced water pipeline operated by Meadowlark Midstream Company, LLC, a subsidiary of the Partnership, that occurred near Williston, North Dakota and was discovered on January 6, 2015. These transactions are collectively referred to as the “GP Buy-In Transaction.”

As a result of the GP Buy-In Transaction, the Partnership indirectly owns its General Partner. Following the closing of the GP Buy-In Transaction, the Partnership retired 16,630,112 SMLP common units it acquired that are not pledged as collateral under the SMPH Term Loan. The 34,604,581 SMLP common units that are pledged as collateral under the SMPH Term Loan are not considered outstanding with respect to voting and distributions under the Partnership Agreement so long as they are held by a subsidiary of the Partnership.

Under GAAP, the GP Buy-In Transaction was deemed a transaction among entities under common control with a change in reporting entity. Although SMLP is the surviving entity for legal purposes, Summit Investments is the surviving entity for accounting purposes; therefore, the historical financial results included herein, prior to the GP Buy-In Transaction are those of Summit Investments. Prior to the GP Buy-In Transaction, Summit Investments controlled SMLP and SMLP’s financial statements were consolidated into Summit Investments.

Business Operations. The Partnership provides natural gas gathering, compression, treating and processing services as well as crude oil and produced water gathering services pursuant to primarily long-term, fee-based agreements with its customers. The Partnership’s results are primarily driven by the volumes of natural gas that it gathers, compresses, treats and/or processes as well as by the volumes of crude oil and produced water that it gathers.

Presentation and Consolidation. The condensed consolidated financial statements contained in this report include all normal and recurring material adjustments that, in the opinion of management, are necessary for a fair statement of the financial position, results of operations and cash flows for the interim periods presented herein.

The accompanying condensed consolidated financial statements were prepared using GAAP for interim financial information and in accordance with the rules and regulations of the Securities and Exchange Commission. As permitted under those rules, certain information relating to the Partnership’s organization and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been appropriately condensed or omitted. Therefore, these condensed consolidated financial statements should be read in conjunction with the

consolidated financial statements and the notes thereto included in the Partnership’s Annual Report for the year ended December 31, 2019 (“2019 Annual Report”). The Partnership believes the disclosures made are adequate to make the information presented not misleading.

Risks and Uncertainties. The Partnership is closely monitoring the impact of the outbreak of COVID-19 on all aspects of its business, including how it has impacted and will impact its customers, employees, supply chain and distribution network. While COVID-19 did not have a material adverse effect on the Partnership’s reported results for the first nine months of 2020, the Partnership is unable to predict the ultimate impact that COVID-19 may have on its business, future results of operations, financial position or cash flows.

Given the dynamic nature of the COVID-19 pandemic and related market conditions, the Partnership cannot reasonably estimate the period of time that these events will persist or the full extent of the impact they will have on its business. The full extent to which the Partnership’s operations may be impacted by the COVID-19 pandemic will depend largely on future developments, which are highly uncertain and cannot be accurately predicted, including changes in the severity of the pandemic, countermeasures taken by governments, businesses and individuals to slow the spread of the pandemic, and the ability of pharmaceutical companies to develop effective and safe vaccines and therapeutic drugs. Furthermore, the impacts of a potential worsening of global economic conditions and the continued disruptions to and volatility in the financial markets remain unknown.

SUMMARY OF RECENTLY ISSUED ACCOUNTING STANDARDS APPLICABLE TO THE PARTNERSHIP

9 Months Ended

Sep. 30, 2020

Accounting Policies [Abstract]

SUMMARY OF RECENTLY ISSUED ACCOUNTING STANDARDS APPLICABLE TO THE PARTNERSHIP

2. SUMMARY OF RECENTLY ISSUED ACCOUNTING STANDARDS APPLICABLE TO THE PARTNERSHIP

Recent Accounting Pronouncements. Accounting standard setters frequently issue new or revised accounting rules. The Partnership reviews new pronouncements to determine the impact, if any, on its financial statements. Accounting standards that have or could possibly have a material effect on the Partnership’s financial statements are discussed below.

Recently Adopted Accounting Pronouncements. The Partnership recently adopted the following accounting pronouncements:

•

ASU No. 2018-13 Fair Value Measurement (“ASU 2018-13”). ASU 2018-13 updates the disclosure requirements on fair value measurements including new disclosures for the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. ASU 2018-13 modifies existing disclosures including clarifying the measurement uncertainty disclosure. ASU 2018-13 removes certain existing disclosure requirements including the amount and reasons for transfers between Level 1 and Level 2 fair value measurements and the policy for the timing of transfer between levels. The adoption of ASU 2018-13 on January 1, 2020 did not have a material impact on the Partnership’s condensed consolidated financial statements or disclosures.

•

ASU No. 2016-13 Financial Instruments – Credit Losses (“ASU 2016-13”). ASU 2016-13 requires the use of a current expected loss model for financial assets measured at amortized cost and certain off-balance sheet credit exposures. Under this model, entities will be required to estimate the lifetime expected credit losses on such instruments based on historical experience, current conditions, and reasonable and supportable forecasts. This amended guidance also expands the disclosure requirements to enable users of financial statements to understand an entity’s assumptions, models and methods for estimating expected credit losses. The changes are effective for annual and interim periods beginning after December 15, 2019, and amendments should be applied using a modified retrospective approach. The adoption of ASU 2016-13 on January 1, 2020 did not have a material impact on the Partnership’s condensed consolidated financial statements or disclosures.

Accounting Pronouncements Not Yet Adopted. The Partnership has not yet adopted the following accounting pronouncements as of September 30, 2020:

•

ASU No. 2020-06 Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815 – 40) (“ASU 2020-06”). ASU 2020-06 simplifies the

accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. The ASU is part of the FASB’s simplification initiative, which aims to reduce unnecessary complexity in U.S. GAAP. The ASU’s amendments are effective for fiscal years beginning after December 15, 2023, and interim periods within those fiscal years. The Partnership is currently evaluating the provisions of ASU 2020-06 to determine its impact on the Partnership’s condensed consolidated financial statements and disclosures.

•

ASU No. 2020-04 Reference Rate Reform (“ASU 2020-04”). ASU 2020-04 provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform on financial reporting. The amendments in ASU 2020-04 are effective as of March 12, 2020 through December 31, 2022. The Partnership is currently evaluating the provisions of ASU 2020-04 to determine its impact on the Partnership’s condensed consolidated financial statements and disclosures.

REVENUE

9 Months Ended

Sep. 30, 2020

Property Plant And Equipment [Abstract]

REVENUE

3. REVENUE

Performance obligations. 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.

	2020		2021		2022		2023		2024		Thereafter
	(In thousands)
Gathering services and related fees	$	29,678	$	102,127	$	84,736	$	66,693	$	50,608	$	56,912

Revenue by Category. In the following table, revenue is disaggregated by geographic area and major products and services. For more detailed information about reportable segments, see Note 16 – Segment Information.

	Three months ended September 30, 2020
	Gathering services and related fees		Natural gas, NGLs and condensate sales		Other revenues		Total
	(in thousands)
Reportable Segments:
Utica Shale	$	8,385	$	-	$	-	$	8,385
Williston Basin		10,941		4,958		3,136		19,035
DJ Basin		6,051		17		826		6,894
Permian Basin		2,595		4,803		168		7,566
Piceance Basin		26,576		528		1,233		28,337
Barnett Shale		10,545		477		1,399		12,421
Marcellus Shale		6,871		—		—		6,871
Total reportable segments		71,964		10,783		6,762		89,509
All other segments		—		—		644		644
Total	$	71,964	$	10,783	$	7,406	$	90,153

	Three months ended September 30, 2019
	Gathering services and related fees		Natural gas, NGLs and condensate sales			Other revenues		Total
	(in thousands)
Reportable Segments:
Utica Shale	$	8,865	$	-		$	-	$	8,865
Williston Basin		16,685		1,878			2,555		21,118
DJ Basin		7,039		93			735		7,867
Permian Basin		986		3,797			102		4,885
Piceance Basin		30,120		1,733			1,258		33,111
Barnett Shale		11,286		4,828			1,706		17,820
Marcellus Shale		5,987		—			—		5,987
Total reportable segments		80,968		12,329			6,356		99,653
All other segments		—		(110	)		644		534
Total	$	80,968	$	12,219		$	7,000	$	100,187

	Nine months ended September 30, 2020
	Gathering services and related fees		Natural gas, NGLs and condensate sales		Other revenues		Total
	(in thousands)
Reportable Segments:
Utica Shale	$	26,885	$	-	$	-	$	26,885
Williston Basin		47,145		12,413		9,054		68,612
DJ Basin		18,134		158		2,853		21,145
Permian Basin		7,617		13,537		481		21,635
Piceance Basin		79,987		1,932		3,394		85,313
Barnett Shale		30,865		7,206		4,437		42,508
Marcellus Shale		19,034		—		—		19,034
Total reportable segments		229,667		35,246		20,219		285,132
All other segments		—		—		1,931		1,931
Total	$	229,667	$	35,246	$	22,150	$	287,063

	Nine months ended September 30, 2019
	Gathering services and related fees			Natural gas, NGLs and condensate sales		Other revenues		Total
	(in thousands)
Reportable Segments:
Utica Shale	$	23,951		$	-	$	-	$	23,951
Williston Basin		58,076			11,231		8,133		77,440
DJ Basin		14,784			279		2,776		17,839
Permian Basin		1,938			10,424		183		12,545
Piceance Basin		92,515			6,139		3,341		101,995
Barnett Shale		35,739			11,705		5,008		52,452
Marcellus Shale		18,081			—		—		18,081
Total reportable segments		245,084			39,778		19,441		304,303
All other segments		(2,045	)		28,660		363		26,978
Total	$	243,039		$	68,438	$	19,804	$	331,281

Contract balances. Contract assets relate to the Partnership’s rights to consideration for work completed but not billed at the reporting date and consist of the estimated MVC shortfall payments expected from customers and unbilled activity associated with contributions in aid of construction. Contract assets are transferred to trade receivables when the rights become unconditional. The following table provides information about contract assets from contracts with customers:

	September 30, 2020
	(In thousands)
Contract assets, January 1, 2020	$	3,902
Additions		16,442
Transfers out		(2,275	)
Contract assets, September 30, 2020	$	18,069

As of September 30, 2020, receivables with customers totaled $53.8 million and contract assets totaled $18.1 million and are included in the accounts receivable caption on the unaudited condensed consolidated balance sheets.

As of December 31, 2019, receivables with customers totaled $90.4 million and contract assets totaled $3.9 million and are included in the accounts receivable caption on the unaudited condensed consolidated balance sheets.

Contract liabilities (deferred revenue) relate to the advance consideration received from customers primarily for contributions in aid of construction. The Partnership recognizes contract liabilities under these arrangements in revenue over the contract period. For the three months ended September 30, 2020 and 2019, the Partnership recognized $2.4 million and $2.4 million of gathering services and related fees, respectively, which are included in the contract liability balance as of the beginning of the period. For the nine months ended September 30, 2020 and 2019, the Partnership recognized $7.1 million and $7.8 million of gathering services and related fees, respectively, which

are included in the contract liability balance at the beginning of the period. See Note 7 – Deferred Revenue for additional details.

PROPERTY, PLANT, AND EQUIPMENT, NET

9 Months Ended

Sep. 30, 2020

PROPERTY, PLANT, AND EQUIPMENT, NET

4. PROPERTY, PLANT AND EQUIPMENT, NET

Details on property, plant and equipment follow.

	September 30, 2020		December 31, 2019
	(In thousands)
Gathering and processing systems and related equipment	$	2,197,087	$	2,182,950
Construction in progress		78,146		78,716
Land and line fill		10,440		10,137
Other		60,589		54,595
Total		2,346,262		2,326,398
Less accumulated depreciation		(505,978)		(443,909)
Property, plant and equipment, net	$	1,840,284	$	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, the Partnership 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, the Partnership performed a recoverability assessment of certain assets within these reporting segments, the results of which are described below.

In March 2019, the Partnership determined that certain processing plant assets in the DJ Basin related to its existing 20 MMcf/d plant would no longer be utilized due to the Partnership’s 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, the Partnership recorded an impairment charge of $34.7 million related to these assets in the first quarter of 2019.

In March 2019, the Partnership determined that certain compressor station assets in the Barnett Shale were impaired and recorded an impairment charge of $10.2 million, comprised of a $9.7 million impairment of fixed assets and a $0.5 million impairment of rights-of-way.

Depreciation expense and capitalized interest follow.

	Three months ended September 30,				Nine months ended September 30,
	2020		2019		2020		2019
	(In thousands)
Depreciation expense	$	21,537	$	19,474	$	64,899	$	58,160
Capitalized interest		1,449		1,391		2,268		5,752

GOODWILL

9 Months Ended

Sep. 30, 2020

Goodwill And Intangible Assets Disclosure [Abstract]

GOODWILL

5. GOODWILL

Goodwill. The Partnership evaluates goodwill for impairment annually on September 30^th. In 2019, the Partnership performed its annual goodwill impairment test for the Mountaineer Midstream reporting unit using a combination of the income and market approaches and determined that the fair value of the Mountaineer Midstream reporting unit did not exceed its carrying value, including goodwill. As a result, the Partnership recognized a goodwill impairment charge of $16.2 million for the three and nine months ended September 30, 2019. The Partnership had no goodwill on its balance sheet after September 30, 2019.

Fair Value Measurement. The Partnership’s impairment determinations, in the context of (i) its annual impairment evaluations and (ii) its other-than-annual impairment evaluations, involve significant assumptions and judgments, as discussed in the 2019 Annual Report. Differing assumptions regarding any of these inputs could have a significant effect on the valuations. As such, the fair value measurements utilized within these models are classified as non-recurring Level 3 measurements in the fair value hierarchy because they are not observable from objective sources.

EQUITY METHOD INVESTMENTS

9 Months Ended

Sep. 30, 2020

Equity Method Investments And Joint Ventures [Abstract]

EQUITY METHOD INVESTMENTS

6. EQUITY METHOD INVESTMENTS

Double E

The Partnership is responsible for leading the development, permitting and construction of the Double E Project. During the three and nine month periods ended September 30, 2020, the Partnership made cash investments of $12.4 million and $92.1 million, respectively, in the Double E Project.

For the three and nine months ended September 30, 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

As of September 30, 2020 and December 31, 2019, the Partnership’s ownership interest in Ohio Gathering was 38.2% and 38.5%, respectively, and provided below is the September 30, 2020 reconciliation of the difference between the carrying amount of the Partnership’s interest in Ohio Gathering and the Partnership’s underlying investment per Ohio Gathering's books and records (in thousands).

Investment in Ohio Gathering, September 30, 2020	$	263,639
September cash distributions		3,870
Basis difference		218,757
Investment in Ohio Gathering (Books and records), August 31, 2020	$	486,266

DEFERRED REVENUE

9 Months Ended

Sep. 30, 2020

PARTNERS' CAPITAL AND MEZZANINE CAPITAL

DEFERRED REVENUE

7. DEFERRED REVENUE

A rollforward of current deferred revenue follows.

	Total
	(In thousands)
Current deferred revenue, January 1, 2020	$	13,493
Additions		15,433
Less: revenue recognized		(11,099)
Current deferred revenue, September 30, 2020	$	17,827

A rollforward of noncurrent deferred revenue follows.

	Total
	(In thousands)
Noncurrent deferred revenue, January 1, 2020	$	38,709
Additions		18,402
Less: reclassification to current deferred revenue		(15,356)
Noncurrent deferred revenue, September 30, 2020	$	41,755

DEBT

9 Months Ended

Sep. 30, 2020

Debt Disclosure [Abstract]

DEBT

8. DEBT

Debt consisted of the following:

	September 30, 2020			December 31, 2019
	(In thousands)
Revolving Credit Facility: Summit Holdings' variable rate senior secured Revolving Credit Facility (2.90% at September 30, 2020 and 4.55% at December 31, 2019) due May 2022	$	808,500		$	677,000
ECP Loans: Summit Holdings' 8.00% senior secured term loans due March 2021		—			—
2022 Senior Notes: Summit Holdings' 5.5% senior unsecured notes due August 2022		234,047			300,000
Less: unamortized debt issuance costs ⁽¹⁾		(997	)		(1,686	)
2025 Senior Notes: Summit Holdings' 5.75% senior unsecured notes due April 2025		355,071			500,000
Less: unamortized debt issuance costs ⁽¹⁾		(3,055	)		(5,015	)
SMPH Term Loan: SMP Holdings' variable rate senior secured term loan (7.00% at September 30, 2020 and 7.80% at December 31, 2019) due May 2022		155,200			161,500
Less: unamortized debt issuance costs ⁽¹⁾		(2,724	)		(3,974	)
Total debt		1,546,042			1,627,825
Less: current portion		(155,200)			(5,546)
Total long-term debt	$	1,390,842		$	1,622,279

⁽¹⁾ Issuance costs are being amortized over the life of the SMPH Term Loan and the Senior Notes.

Revolving Credit Facility. The Partnership’s subsidiary, Summit Holdings, has a senior secured revolving credit facility (the “Revolving Credit Facility”) which allows for revolving loans, letters of credit and swingline loans. The Revolving Credit Facility has a $1.25 billion borrowing capacity, matures in May 2022, and includes a $250.0 million accordion feature. At September 30, 2020, the applicable margin under LIBOR borrowings was 2.75%, the interest rate was 2.90% and the unused portion of the Revolving Credit Facility totaled $437.4 million, subject to a commitment fee of 0.50%, after giving effect to the issuance thereunder of a $4.1 million outstanding but undrawn irrevocable standby letter of credit. Based on covenant limits, our available borrowing capacity under the Revolving Credit Facility as of September 30, 2020 was approximately $172.0 million. As of and during the nine months ended September 30, 2020, we were in compliance with the Revolving Credit Facility's financial covenants. There were no defaults or events of default during the nine months ended September 30, 2020.

Significant updates to the Partnership’s indebtedness for the three and nine months ended September 30, 2020 included the following matters.

ECP Loans. On May 28, 2020, in connection with the closing of the GP Buy-In Transaction, Summit Holdings, entered into (i) a Term Loan Credit Agreement (the “ECP NewCo Term Loan Credit Agreement”), with SMP TopCo, LLC, a Delaware limited liability company and affiliate of ECP (“ECP NewCo”), as lender and administrative agent, and Mizuho Bank (USA) (“Mizuho”), as collateral agent, in a principal amount of $28.2 million (the “ECP NewCo Loan”), and (ii) a Term Loan Credit Agreement (the “ECP Holdings Term Loan Credit Agreement” and together with the ECP NewCo Term Loan Credit Agreement, the “ECP Term Loan Credit Agreements”), with ECP Holdings, as lender, and ECP NewCo, as administrative agent and Mizuho, as collateral agent, in a principal amount of $6.8 million (the “ECP Holdings Loan” and together with the ECP NewCo Loan, the “ECP Loans”). The ECP Loans were set to mature on March 31, 2021 and bore interest at a rate of 8.00% per annum, with the interest payment due at maturity of the ECP Loans. With borrowings under the Partnership’s Revolving Credit Facility, the Partnership fully repaid all amounts outstanding under the ECP Loans ($35 million of principal and $0.6 million of accrued interest) on August 7, 2020.

SMPH Term Loan. On April 17, 2020, the Partnership entered into a derivative financial instrument to convert a portion of its variable rate SMPH Term Loan to a fixed rate debt consisting of a 1% LIBOR interest rate cap for a fee of $0.2 million (exclusive of the applicable bank margin charged by our lender) on a $125.0 million notional amount

beginning April 30, 2020 and ending on April 30, 2022. The Partnership did not designate the interest rate cap for hedge accounting as defined by GAAP and recognized an unsettled gain of $0.1 million on the interest rate cap in the other income line item on our unaudited condensed consolidated statement of operations for the three and nine month periods ended September 30, 2020.

Liability Management Transactions. During the three and nine months ended September 30, 2020, the Partnership completed several liability management transactions, described below, that resulted in the early extinguishment of $210.8 million of the Partnership’s 2022 and 2025 Senior Notes.

Open Market Repurchases. During the nine months ended September 30, 2020, the Partnership made a number of open market repurchases of its 2022 and 2025 Senior Notes that resulted in the extinguishment of $32.4 million of face value of the 2022 Senior Notes and $106.2 million of face value of the 2025 Senior Notes (the “Open Market Repurchases”). Total cash consideration paid to repurchase the principal amounts outstanding of the 2022 and 2025 Senior Notes, plus accrued interest totaled $82.9 million and the Partnership recognized a $56.2 million gain on the extinguishment of debt during the nine months ended September 30, 2020.

Tender Offers. In September 2020, the Partnership completed cash tender offers (the “Tender Offers”) to purchase a portion of the 2022 and 2025 Senior Notes. Upon concluding the Tender Offers, the Partnership repurchased $33.5 million principal amount of the 2022 Senior Notes and $38.7 million principal amount of the 2025 Senior Notes. Total cash consideration paid to repurchase the principal amounts outstanding of the 2022 and 2025 Senior Notes, plus accrued interest, totaled $48.7 million and the Partnership recognized a $23.3 million gain on the extinguishment of debt during the nine months ended September 30, 2020.

SMPH Term Loan Restructuring. On September 29, 2020, SMP Holdings and the Partnership entered into the Transaction Support Agreement (the “TSA”) with an ad hoc group of SMP Holdings’ lenders under the $155.2 million SMPH Term Loan (the “Term Loan Lenders”) that will result in a consensual debt discharge and restructuring transaction (the “TL Restructuring”) of the full amount owed under SMPH Term Loan in exchange for (i) a cash payment of $26.5 million to the Term Loan Lenders, (ii) the execution of a strict foreclosure by the collateral agent under the SMPH Term Loan for the benefit of the Term Loan Lenders on the 34.6 million SMLP common units pledged as collateral under the SMPH Term Loan, and (iii) the payment of certain fees and expenses by the Partnership. Upon consummation of the TL Restructuring, which is expected to occur during the quarterly period ended December 31, 2020, the SMPH Term Loan will be fully satisfied and cease to exist. Upon closing of the TL Restructuring the Partnership will recognize a gain equal to the difference between the face value of the cancelled debt and the fair value of the total consideration transferred, including unamortized debt issuance costs, and certain direct transaction costs related to the restructuring. As a result of the TL Restructuring, at September 30, 2020 the Partnership classified the SMPH Term Loan as current. Concurrently with the closing of the TL Restructuring, the Partnership will make a $26.5 million cash payment on the Deferred Purchase Price Obligation to SMP Holdings and fully settle the obligation.

Gain on Extinguishment of Debt. The Partnership recognized a $78.9 million gain on extinguishment of debt during the nine months ended September 30, 2020, primarily as the result of the its Open Market Repurchases and its Tender Offers.

	ECP Loan Repayment			Open Market Repurchases						Tender Offers						Total
				2022			2025			2022			2025
				Senior Notes			Senior Notes			Senior Notes			Senior Notes
	(in thousands)
Gain on repurchases of Senior Notes	$	-		$	11,554		$	46,003		$	9,223		$	15,479		$	82,259
Debt issue costs		(361	)		(143	)		(965	)		(125	)		(351	)		(1,945	)
Transaction cost		(249	)		(105	)		(105	)		(465	)		(465	)		(1,389	)
Gain (loss) on extinguishment	$	(610	)	$	11,306		$	44,933		$	8,633		$	14,663		$	78,925

FINANCIAL INSTRUMENTS

9 Months Ended

Sep. 30, 2020

Fair Value Disclosures [Abstract]

FINANCIAL INSTRUMENTS

9. FINANCIAL INSTRUMENTS

Fair Value. A summary of the estimated fair value of our debt financial instruments follows.

	September 30, 2020				December 31, 2019
	Carrying Value, Net		Estimated fair value (Level 2)		Carrying Value, Net		Estimated fair value (Level 2)
	(In thousands)
2022 Senior Notes	$	233,050	$	169,684	$	298,314	$	266,750
2025 Senior Notes		352,016		204,758		494,985		382,708

The carrying value on the balance sheet of the Revolving Credit Facility is its fair value due to their floating interest rates. The fair value for the 2022 and 2025 Senior Notes is based on an average of nonbinding broker quotes. The use of different market assumptions or valuation methodologies may have a material effect on the estimated fair value of the 2022 and 2025 Senior Notes.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

PARTNERS' CAPITAL AND MEZZANINE CAPITAL

9 Months Ended

Sep. 30, 2020

Equity [Abstract]

10. PARTNERS' CAPITAL AND MEZZANINE CAPITAL

A rollforward of the number of common units follows.

	Common Units
Units, December 31, 2019⁽¹⁾		45,318,866
Net units issued under the SMLP LTIP		1,028,654
Impact of GP Buy-In Transaction		(1,990,303	)
Preferred Unit Exchange		12,267,670
Units, September 30, 2020⁽¹⁾		56,624,887

⁽¹⁾ As a result of the GP Buy-In Transaction, the Partnership recast its historical financial statements, which resulted in a recasted SMLP common limited partner unit count of 45.3 million units at December 31, 2019. Prior to the GP Buy-In Transaction, the SMLP common limited partner unit count was 94.5 million units, and after adjusting for (i) the effect of 1.0 million SMLP units issued following the closing of the GP Buy-In transaction through September 30, 2020 for the SMLP LTIP, (ii) the 12.3 million SMLP common units issued in the Exchange Offer, and (iii) the GP Buy-In Transaction which included the Partnership acquiring SMP Holdings which owns the 34.6 million SMLP units pledged under the SMPH Term Loan, the 10.7 million SMLP units not pledged under the SMPH Term Loan, and the 5.9 million SMLP units owned by ECP, the SMLP common limited partner unit count would have been an otherwise identical 56.6 million SMLP common units at September 30, 2020.

GP Buy-In Transaction. The purchase price for the SMLP common units reflected in the unaudited condensed consolidated statement of partners’ capital for the nine months ended September 30, 2020 is comprised of the (i) the $35.0 million cash payment to ECP, (ii) the $2.3 million fair value for the issuance of 10,000,000 warrants, and (iii) $6.8 million of advisory fees and other direct costs related to closing the GP Buy-In Transaction.

Series A Preferred Units. In 2017, the Partnership issued 300,000 Series A Preferred Units representing limited partner interests in the Partnership at a price to the public of $1,000 per unit as described in the 2019 Annual Report. In connection with the GP Buy-In Transaction, the Partnership suspended its distributions to holders of its Series A Preferred Units, commencing with respect to the quarter ending March 31, 2020. On June 18, 2020, the Partnership, commenced an offer to exchange any and all of its Series A Preferred Units for newly issued SMLP common units (the “Exchange Offer”). On July 28, 2020, the Exchange Offer expired and the Partnership exchanged 62,816 Series A Preferred Units for 12,267,670 SMLP common units, net of units withheld for tax withholdings. As of September 30, 2020, the Partnership had 237,184 Series A Preferred Units outstanding.

Subsidiary Series A Preferred Units. The Partnership issued 53,784 Subsidiary Series A Preferred Units during the nine months ended September 30, 2020 at a price of $1,000 per unit and has cumulatively issued 83,842 Subsidiary Series A Preferred Units since the instrument’s initial issuance in December 2019. Net proceeds received during the nine months ended September 30, 2020 totaled $48.7 million (after deducting underwriting discounts and offering expenses) and were used to fund the Partnership’s share of capital expenditures associated with the Double E Project. The proceeds associated with the issuance of Subsidiary Series A Preferred Units are restricted for funding the Double E Project and are classified as restricted cash in the accompanying unaudited condensed consolidated balance sheets.

The Partnership records its Subsidiary Series A Preferred Units at fair value upon issuance, net of issuance costs, and subsequently records an effective interest method accretion amount each reporting period to accrete the carrying value to a most probable redemption value that is based on a predetermined internal rate of return measure. The Partnership also elected to make payment-in-kind (“PIK”) distributions to holders of the Subsidiary Series A Preferred Units during the nine months ended September 30, 2020 and these PIK distributions increase the liquidation preference on each Subsidiary Series A Preferred Unit. Ultimately, Net Income (Loss) Attributable to common limited partners includes adjustments for PIK distributions and redemption accretion.

If the Subsidiary Series A Preferred Units were redeemed on September 30, 2020, the redemption amount would be $104.8 million when considering the applicable multiple of invested capital metric and make-whole amount provisions contained in the Subsidiary Series A Preferred Unit agreement. The following table shows the change in our Subsidiary Series A Preferred Unit balance from December 31, 2019 to September 30, 2020:

	September 30, 2020
	(in thousands)
Balance at December 31, 2019	$	27,450
New issuances		50,000
PIK distributions		3,784
Issuance costs		(1,290	)
Redemption accretion		5,856
Balance at September 30, 2020⁽¹⁾	$	85,800

⁽¹⁾ Amount is net of $3.9 million of issuance costs at September 30, 2020.

Warrants. On May 28, 2020 and in connection with the GP Buy-In Transaction, the Partnership issued (i) a warrant to purchase up to 8,059,609 SMLP common units to ECP NewCo (the “ECP NewCo Warrant”) and (ii) a warrant to purchase up to 1,940,391 SMLP common units to ECP Holdings (the “ECP Holdings Warrant” and together with the ECP NewCo Warrant, the “ECP Warrants”). The exercise price under the ECP Warrants is $1.023 per SMLP common unit and the Partnership may issue a maximum of 10,000,000 SMLP common units under the ECP Warrants.

Upon exercise of the ECP Warrants, each of ECP NewCo and ECP Holdings may receive, at its election: (i) a number of SMLP common units equal to the number of SMLP common units for which the ECP Warrants are being exercised, if exercising the ECP Warrants by cash payment of the exercise price; (ii) a number of SMLP common units equal to the product of the number of common units being exercised multiplied by (a) the difference between the average of the daily volume-weighted average price (“VWAP”) of the SMLP common units on the New York Stock Exchange (the “NYSE”) on each of the three trading days prior to the delivery of the notice of exercise (the “VWAP Average”) and the exercise price (the “VWAP Difference”), divided by (b) the VWAP Average; and/or (iii) an amount in cash, to the extent that the Partnership’s leverage ratio would be at least 0.5x less than the maximum applicable ratio set forth in the Revolving Credit Facility, equal to the product of (a) the number of SMLP common units exercised and (b) the VWAP Difference, subject to certain adjustments under the ECP Warrants.

The ECP Warrants are subject to standard anti-dilution adjustments for stock dividends, stock splits (including reverse splits) and recapitalizations and are exercisable at any time on or before May 28, 2023. Upon exercise of the ECP Warrants, the proceeds to the holders of the ECP Warrants, whether in the form of cash or common units, will be capped at $2.00 per SMLP common unit above the exercise price.

At issuance the ECP Warrants were valued at $2.3 million using a Black-Scholes model and accounted for as a liability instrument. At September 30, 2020, the ECP Warrants were valued at $1.5 million.

SMLP General Partner and Incentive Distribution Rights (“IDR”) Exchange. In March 2019, and prior to the GP Buy-In Transaction, a subsidiary of Summit Investments cancelled its IDR agreement with SMLP and converted its 2% economic general partner interest to a non-economic general partner interest in exchange for 8,750,000 SMLP common units. This exchange is reflected in the Consolidated Statements of Partners’ Capital as a reduction to noncontrolling interest and an increase to Partners’ Capital.

Cash Distributions Paid and Declared. Prior to the GP Buy-In Transaction, SMLP paid the following per-unit distributions during the three and nine month periods ended September 30 (all payments represent per-unit distributions based on the SMLP common units outstanding prior to the GP Buy-In Transaction):

	Three months ended September 30,				Nine months ended September 30,
	2020		2019		2020		2019
Per-unit distributions to unitholders	$	—	$	0.2875	$	0.125	$	1.1500

In connection with the GP Buy-In Transaction, the Partnership suspended its distributions to holders of its common units, commencing with respect to the quarter ending March 31, 2020.

With respect to our Subsidiary Series A Preferred Units relating to the three and nine months ended September 30, 2020, the Partnership declared a PIK of the quarterly distribution, which resulted in the issuance of 45 Subsidiary Series A Preferred Units and 1,442 Subsidiary Series A Preferred Units, respectively. This PIK amount equates to a distribution of $32.1133 and $17.5099 per Subsidiary Series A Preferred Unit for the three and nine months ended September 30, 2020, respectively, or $70 on an annualized basis. In addition, the Partnership issued approximately 38 Subsidiary Series A Preferred Units related to the remaining undrawn commitment (as defined in the underlying agreement with TPG Energy Solutions Anthem, L.P.) as of and for the nine months ended September 30, 2020.

EARNINGS PER UNIT

9 Months Ended

Sep. 30, 2020

Earnings Per Share [Abstract]

EARNINGS PER UNIT

11. EARNINGS PER UNIT

The following table details the components of EPU.

	Three months ended September 30,					Nine months ended September 30,
	2020		2019			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	$	25,629	$	(789	)	$	89,386	$	(11,130	)
Less:
Net income attributable to Series A Preferred Units		6,481		7,125			20,731		21,375
Net income attributable to Subsidiary Series A Preferred Units		7,298		—			9,640		—
Add:
Deemed capital contribution from Series A Preferred Unit Exchange Offer		54,945		—			54,945		—
Net income (loss) attributable to common limited partners	$	66,795	$	(7,914	)	$	113,960	$	(32,505	)

Denominator for basic and diluted EPU:
Weighted-average common units outstanding – basic⁽¹⁾		51,974		45,319			47,331		45,319
Effect of nonvested phantom units		1,676		—			1,451		—
Weighted-average common units outstanding – diluted		53,650		45,319			48,782		45,319

Net Income (Loss) per limited partner unit:
Common unit – basic	$	1.29	$	(0.17	)	$	2.41	$	(0.72	)
Common unit – diluted	$	1.25	$	(0.17	)	$	2.34	$	(0.72	)

Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU		4,031		176			3,353		70

⁽¹⁾ As a result of the GP Buy-In Transaction, our historical results are those of Summit Investments. The number of common units of 45.3 million as of September 30, 2019 represents those of Summit Investments and has been used for the earnings per unit calculations presented herein.

As discussed in Note 8 - Debt, the SMPH Term Loan is secured by 34.6 million SMLP common units owned by SMP Holdings. These common units are not included in the calculation of EPU because they are not deemed contingently issuable under GAAP. Upon closing the TL Restructuring, the 34.6 million SMLP common units pledged under the SMPH Term Loan will be considered outstanding and included in the calculation of EPU.

SUPPLEMENTAL CASH FLOW INFORMATION

9 Months Ended

Sep. 30, 2020

Supplemental Cash Flow Elements [Abstract]

SUPPLEMENTAL CASH FLOW INFORMATION

12. SUPPLEMENTAL CASH FLOW INFORMATION

	Nine months ended September 30,
	2020		2019
	(In thousands)
Supplemental cash flow information:
Cash interest paid	$	62,441	$	66,435
Less capitalized interest		2,268		5,752
Interest paid (net of capitalized interest)	$	60,173	$	60,683

Cash paid for taxes	$	—	$	150

Noncash investing and financing activities:
Capital expenditures in trade accounts payable (period-end accruals)	$	10,233	$	22,166
Warrant issuance for GP Buy-In Transaction		2,300		—
Asset contribution to an equity method investment		—		23,643
Right-of-use assets relating to ASC Topic 842		2,964		5,448
Accretion of Subsidiary Series A Preferred Units		5,856		—

UNIT-BASED AND NONCASH COMPENSATION

9 Months Ended

Sep. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

UNIT-BASED AND NONCASH COMPENSATION

13. UNIT-BASED AND NONCASH COMPENSATION

SMLP Long-Term Incentive Plan. The SMLP LTIP provides for equity awards to eligible officers, employees, consultants and directors. Items to note:

•

In March 2020, the Partnership granted 3,811,301 phantom units and associated distribution equivalent rights to employees in connection with the Partnership’s 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, the Partnership issued 549,450 common units to the Partnership’s three independent directors in connection with their annual compensation plan.

•

In June 2020, the Partnership issued 187,500 common units to three new independent directors in connection with their annual compensation plan.

•

During the nine months ended September 30, 2020, 0.8 million phantom units vested.

•

In March 2020, the Partnership 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 September 30, 2020, approximately 6.3 million common units remained available for future issuance under the SMLP LTIP.

COMMITMENTS AND CONTINGENCIES

9 Months Ended

Sep. 30, 2020

Commitments And Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

14. COMMITMENTS AND CONTINGENCIES

Environmental Matters. Although the Partnership believes that it is in material compliance with applicable environmental regulations, the risk of environmental remediation costs and liabilities are inherent in pipeline ownership and operation. Furthermore, the Partnership can provide no assurances that significant environmental remediation costs and liabilities will not be incurred by the Partnership in the future. The Partnership is not aware of any material contingent liabilities that exist with respect to environmental matters, except as noted below.

In 2015, the Partnership 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 Partnership’s undiscounted accrued environmental remediation liabilities follows.

	Total
	(In thousands)
Accrued environmental remediation, January 1, 2020	$	4,651
Payments made		(1,095	)
Accrued environmental remediation, September 30, 2020	$	3,556

As of September 30, 2020, the Partnership has 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 expected to be incurred subsequent to September 30, 2021. Each of these amounts represent our best estimate for costs expected to be incurred. Neither of these amounts have been discounted to its present value.

Prior to the GP Buy-In Transaction, Summit Investments and SMP Holdings indemnified the Partnership for certain obligations and liabilities related to the incident. As a result of the GP Buy-In Transaction, the Partnership continues to be indemnified by Summit Investments and SMP Holdings, both subsidiaries of the Partnership, but is no longer indemnified for these obligations by a third party that is not a subsidiary of the Partnership.

The U.S. Department of Justice issued grand jury subpoenas to the Partnership requesting certain materials related to the Meadowlark Midstream rupture. Based on information currently available to the Partnership, the Partnership believes a loss for claims and/or actions arising from the Meadowlark Midstream rupture is probable. Due to the complexity surrounding the resolution of the Meadowlark Midstream rupture, the Partnership is not able to reasonably estimate the extent of the Partnership’s loss for this matter, or to express an opinion regarding the ultimate outcome. Any such loss, if incurred, could be material.

Legal Proceedings. The Partnership is involved in various litigation and administrative proceedings arising in the normal course of business. In the opinion of management, any liabilities that may result from these claims or those arising in the normal course of business would not individually or in the aggregate have a material adverse effect on the Partnership's financial position or results of operations.

DISPOSITIONS AND RESTRUCTURING

9 Months Ended

Sep. 30, 2020

Business Combinations [Abstract]

DISPOSITIONS AND RESTRUCTURING

15. DISPOSITIONS AND RESTRUCTURING

Tioga Midstream Disposition. In February 2019, the Partnership entered into two Purchase and Sale Agreements (the “Tioga PSAs”) with Hess Infrastructure Partners LP and Hess North Dakota Pipelines LLC (collectively, “Hess Infrastructure”), pursuant to which the Partnership agreed to sell the Tioga Midstream system to Hess Infrastructure for a combined cash purchase price of $90 million, subject to adjustments as provided in the Tioga PSAs (the “Tioga Midstream Sale”). On March 22, 2019, the Partnership closed the Tioga Midstream Sale and recorded a gain on sale of $0.9 million based on the difference between the consideration received and the carrying value for Tioga Midstream at closing. The gain is included in the Gain on asset sales, net caption on the unaudited condensed consolidated statement of operations. The financial results of Tioga Midstream (a component of the Williston Basin reportable segment) are included in the Partnership’s unaudited condensed consolidated financial statements and footnotes for the period from January 1, 2019 through March 22, 2019.

Restructuring Activities. As of December 31, 2019, the Partnership had $3.3 million of unpaid employee severance costs related to 2019 restructuring initiatives that resulted in certain management, facility and organizational changes. During the three and nine month periods ended September 30, 2020, the Partnership’s 2019 restructuring initiatives resulted in additional restructuring costs of $0.1 million and $3.4 million, respectively. The Partnership paid out $6.4 million of these 2019 restructuring costs during the nine months ended September 30, 2020 and has a $0.3 million current liability for unpaid employee severance costs at September 30, 2020 related to these 2019 restructuring initiatives. The 2019 restructuring activities primarily consisted of employee-related costs and consulting costs in support of the restructuring initiatives. Restructuring costs are included within the general and administrative expense caption on the condensed consolidated statement of operations.

SEGMENT INFORMATION

9 Months Ended

Sep. 30, 2020

Segment Reporting [Abstract]

SEGMENT INFORMATION

16. SEGMENT INFORMATION

As of September 30, 2020, the Partnership’s 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, Bison Midstream and Meadowlark 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, the Partnership owned Tioga Midstream, a crude oil, produced water and associated natural gas gathering system operating in the Williston Basin. Refer to Note 15 – Dispositions and Restructuring to the unaudited condensed consolidated financial statements for details on the sale of Tioga Midstream.

Each of the Partnership’s reportable segments provide midstream services in a specific geographic area and reflect the way in which the Partnership internally reports the financial information used to make decisions and allocate resources in connection with the Partnership’s operations.

For the three and nine months ended September 30, 2020, other than the investment activity described in Note 6 – Equity Method Investments, 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 fourth 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 the Partnership’s 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.

	September 30, 2020		December 31, 2019
	(In thousands)
Assets⁽¹⁾:
Utica Shale	$	208,090	$	206,368
Ohio Gathering		263,639		275,000
Williston Basin		443,506		452,152
DJ Basin		204,206		205,308
Permian Basin		167,707		185,708
Piceance Basin		596,148		631,140
Barnett Shale		349,254		350,638
Marcellus Shale		182,900		184,631
Total reportable segment assets		2,415,450		2,490,945
Corporate and Other		158,029		83,153
Total assets	$	2,573,479	$	2,574,098

⁽¹⁾

^{At September 30, 2020, Corporate and Other included $125.4 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.}

Segment adjusted EBITDA by reportable segment follows.

	Three months ended September 30,				Nine months ended September 30,
	2020		2019		2020		2019
	(In thousands)
Reportable segment adjusted EBITDA
Utica Shale	$	7,453	$	7,864	$	24,074	$	20,697
Ohio Gathering		7,129		10,435		22,582		29,584
Williston Basin		11,713		13,840		40,632		49,224
DJ Basin		4,766		6,554		15,016		12,043
Permian Basin		893		210		4,302		(996	)
Piceance Basin		21,503		24,044		66,794		74,627
Barnett Shale		7,205		10,901		24,475		33,483
Marcellus Shale		6,022		4,958		16,230		14,735
Total of reportable segments' measures of profit	$	66,684	$	78,806	$	214,105	$	233,397

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 follows.

	Three months ended September 30,						Nine months ended September 30,
	2020			2019			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	$	25,132		$	(10,431	)	$	78,862		$	(45,757	)
Add:
Corporate and Other expense		6,874			7,119			28,484			32,024
Interest expense		19,018			23,462			64,836			68,547
Gain on early extinguishment of debt		(24,690	)		—			(78,925	)		—
Depreciation and amortization⁽¹⁾		29,739			27,677			89,505			83,030
Proportional adjusted EBITDA for equity method investees		7,129			10,435			22,582			29,584
Adjustments related to MVC shortfall payments		2,292			3,534			(859	)		2,868
Adjustments related to capital reimbursement activity		(328	)		(145	)		(776	)		(1,906	)
Unit-based and noncash compensation		1,622			1,291			6,191			5,370
Gain on asset sales, net		(104	)		(347	)		(270	)		(1,595	)
Long-lived asset impairment		—			—			4,475			45,021
Goodwill impairment		—			16,211			—			16,211
Total of reportable segments' measures of profit	$	66,684		$	78,806		$	214,105		$	233,397

⁽¹⁾ Includes the amortization expense associated with our favorable gas gathering contracts as reported in other revenues.

SUBSEQUENT EVENTS

9 Months Ended

Sep. 30, 2020

Subsequent Events [Abstract]

SUBSEQUENT EVENTS

17. SUBSEQUENT EVENTS

Open Market Repurchases of 2025 Senior Notes. In October 2020, the Partnership repurchased an additional $95.6 million of the outstanding 2025 Senior Notes for total cash consideration of $64.8 million.

TL Restructuring. In October 2020, the Partnership obtained consents for the TL Restructuring from 100% of the Term Loan Lenders and subsequently filed a Form S-1 registration statement with the Securities and Exchange Commission on November 3, 2020 to register the 34.6 million SMLP common units to be issued to the lenders of the SMPH Term Loan upon consummation of the TL Restructuring. Once the Form S-1 registration statement becomes effective and administrative procedures are performed, the Partnership will close the TL Restructuring and recognize a gain on early debt extinguishment.

Reverse Unit Split. On October 15, 2020, the Board of Directors of the General Partner authorized a reverse unit split (the “Reverse Unit Split”) of the Partnership’s common units. The exchange ratio of the Reverse Unit Split is 1-for-15 and will be effective on November 9, 2020. The common units will begin trading on a split-adjusted basis on November 10, 2020. The Reverse Unit Split is intended to, among other things, increase the per unit trading price of the Partnership’s common units to satisfy the $1.00 minimum bid price requirement for continued listing on the NYSE. As a result of the Reverse Unit Split, each 15 pre-split common units will automatically be combined into one issued and outstanding common unit without any action on the part of the unitholder. Any fractional common units issued as a result of the Reverse Unit Split will be rounded to the nearest whole number of common units. Once effective, the number of outstanding shares of common units will be reduced from 56,624,887 common units as of October 30, 2020 to 3,774,992 common units.

FERC Approval. In October 2020, Double E received Federal Energy Regulatory Commission ("FERC") approval of its application to construct and operate the Double E Pipeline Project, pursuant to Section 7(c) of the Natural Gas Act. Upon fulfilling certain remaining requirements, including finalizing a right-of-way grant from the Bureau of Land Management and filing an implementation plan with the FERC, Double E expects to receive FERC's notice to proceed with construction.

SUMMARY OF RECENTLY ISSUED ACCOUNTING STANDARDS APPLICABLE TO THE PARTNERSHIP (Policies)

9 Months Ended

Sep. 30, 2020

Accounting Policies [Abstract]

Recent Accounting Pronouncements

Recently Adopted Accounting Pronouncements. The Partnership recently adopted the following accounting pronouncements:

•

Accounting Pronouncements Not Yet Adopted. The Partnership has not yet adopted the following accounting pronouncements as of September 30, 2020:

•

Basis of Presentation

REVENUE (Tables)

9 Months Ended

Sep. 30, 2020

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.

	2020		2021		2022		2023		2024		Thereafter
	(In thousands)
Gathering services and related fees	$	29,678	$	102,127	$	84,736	$	66,693	$	50,608	$	56,912

Schedule of Disaggregated Revenue by Geographic Area and Major Products and Services Reportable Segments

	Three months ended September 30, 2020
	Gathering services and related fees		Natural gas, NGLs and condensate sales		Other revenues		Total
	(in thousands)
Reportable Segments:
Utica Shale	$	8,385	$	-	$	-	$	8,385
Williston Basin		10,941		4,958		3,136		19,035
DJ Basin		6,051		17		826		6,894
Permian Basin		2,595		4,803		168		7,566
Piceance Basin		26,576		528		1,233		28,337
Barnett Shale		10,545		477		1,399		12,421
Marcellus Shale		6,871		—		—		6,871
Total reportable segments		71,964		10,783		6,762		89,509
All other segments		—		—		644		644
Total	$	71,964	$	10,783	$	7,406	$	90,153

	Three months ended September 30, 2019
	Gathering services and related fees		Natural gas, NGLs and condensate sales			Other revenues		Total
	(in thousands)
Reportable Segments:
Utica Shale	$	8,865	$	-		$	-	$	8,865
Williston Basin		16,685		1,878			2,555		21,118
DJ Basin		7,039		93			735		7,867
Permian Basin		986		3,797			102		4,885
Piceance Basin		30,120		1,733			1,258		33,111
Barnett Shale		11,286		4,828			1,706		17,820
Marcellus Shale		5,987		—			—		5,987
Total reportable segments		80,968		12,329			6,356		99,653
All other segments		—		(110	)		644		534
Total	$	80,968	$	12,219		$	7,000	$	100,187

	Nine months ended September 30, 2020
	Gathering services and related fees		Natural gas, NGLs and condensate sales		Other revenues		Total
	(in thousands)
Reportable Segments:
Utica Shale	$	26,885	$	-	$	-	$	26,885
Williston Basin		47,145		12,413		9,054		68,612
DJ Basin		18,134		158		2,853		21,145
Permian Basin		7,617		13,537		481		21,635
Piceance Basin		79,987		1,932		3,394		85,313
Barnett Shale		30,865		7,206		4,437		42,508
Marcellus Shale		19,034		—		—		19,034
Total reportable segments		229,667		35,246		20,219		285,132
All other segments		—		—		1,931		1,931
Total	$	229,667	$	35,246	$	22,150	$	287,063

	Nine months ended September 30, 2019
	Gathering services and related fees			Natural gas, NGLs and condensate sales		Other revenues		Total
	(in thousands)
Reportable Segments:
Utica Shale	$	23,951		$	-	$	-	$	23,951
Williston Basin		58,076			11,231		8,133		77,440
DJ Basin		14,784			279		2,776		17,839
Permian Basin		1,938			10,424		183		12,545
Piceance Basin		92,515			6,139		3,341		101,995
Barnett Shale		35,739			11,705		5,008		52,452
Marcellus Shale		18,081			—		—		18,081
Total reportable segments		245,084			39,778		19,441		304,303
All other segments		(2,045	)		28,660		363		26,978
Total	$	243,039		$	68,438	$	19,804	$	331,281

Schedule of Information about Contract Assets from Contracts with Customers

The following table provides information about contract assets from contracts with customers:

	September 30, 2020
	(In thousands)
Contract assets, January 1, 2020	$	3,902
Additions		16,442
Transfers out		(2,275	)
Contract assets, September 30, 2020	$	18,069

PROPERTY, PLANT, AND EQUIPMENT, NET (Tables)

9 Months Ended

Sep. 30, 2020

Property Plant And Equipment [Abstract]

Schedule of property, plant, and equipment, net

Details on property, plant and equipment follow.

	September 30, 2020		December 31, 2019
	(In thousands)
Gathering and processing systems and related equipment	$	2,197,087	$	2,182,950
Construction in progress		78,146		78,716
Land and line fill		10,440		10,137
Other		60,589		54,595
Total		2,346,262		2,326,398
Less accumulated depreciation		(505,978)		(443,909)
Property, plant and equipment, net	$	1,840,284	$	1,882,489

Schedule of depreciation expense and capitalized interest costs

Depreciation expense and capitalized interest follow.

	Three months ended September 30,				Nine months ended September 30,
	2020		2019		2020		2019
	(In thousands)
Depreciation expense	$	21,537	$	19,474	$	64,899	$	58,160
Capitalized interest		1,449		1,391		2,268		5,752

EQUITY METHOD INVESTMENTS (Tables)

9 Months Ended

Sep. 30, 2020

Equity Method Investments And Joint Ventures [Abstract]

Equity Method Investments

Investment in Ohio Gathering, September 30, 2020	$	263,639
September cash distributions		3,870
Basis difference		218,757
Investment in Ohio Gathering (Books and records), August 31, 2020	$	486,266

DEFERRED REVENUE (Tables)

9 Months Ended

Sep. 30, 2020

Rollforward of deferred revenue

A rollforward of current deferred revenue follows.

	Total
	(In thousands)
Current deferred revenue, January 1, 2020	$	13,493
Additions		15,433
Less: revenue recognized		(11,099)
Current deferred revenue, September 30, 2020	$	17,827

A rollforward of noncurrent deferred revenue follows.

	Total
	(In thousands)
Noncurrent deferred revenue, January 1, 2020	$	38,709
Additions		18,402
Less: reclassification to current deferred revenue		(15,356)
Noncurrent deferred revenue, September 30, 2020	$	41,755

DEBT (Tables)

9 Months Ended

Sep. 30, 2020

Debt Disclosure [Abstract]

Schedule of debt and capital leases

Debt consisted of the following:

	September 30, 2020			December 31, 2019
	(In thousands)
Revolving Credit Facility: Summit Holdings' variable rate senior secured Revolving Credit Facility (2.90% at September 30, 2020 and 4.55% at December 31, 2019) due May 2022	$	808,500		$	677,000
ECP Loans: Summit Holdings' 8.00% senior secured term loans due March 2021		—			—
2022 Senior Notes: Summit Holdings' 5.5% senior unsecured notes due August 2022		234,047			300,000
Less: unamortized debt issuance costs ⁽¹⁾		(997	)		(1,686	)
2025 Senior Notes: Summit Holdings' 5.75% senior unsecured notes due April 2025		355,071			500,000
Less: unamortized debt issuance costs ⁽¹⁾		(3,055	)		(5,015	)
SMPH Term Loan: SMP Holdings' variable rate senior secured term loan (7.00% at September 30, 2020 and 7.80% at December 31, 2019) due May 2022		155,200			161,500
Less: unamortized debt issuance costs ⁽¹⁾		(2,724	)		(3,974	)
Total debt		1,546,042			1,627,825
Less: current portion		(155,200)			(5,546)
Total long-term debt	$	1,390,842		$	1,622,279

⁽¹⁾ Issuance costs are being amortized over the life of the SMPH Term Loan and the Senior Notes.

Schedule of extinguishment of debt

	ECP Loan Repayment			Open Market Repurchases						Tender Offers						Total
				2022			2025			2022			2025
				Senior Notes			Senior Notes			Senior Notes			Senior Notes
	(in thousands)
Gain on repurchases of Senior Notes	$	-		$	11,554		$	46,003		$	9,223		$	15,479		$	82,259
Debt issue costs		(361	)		(143	)		(965	)		(125	)		(351	)		(1,945	)
Transaction cost		(249	)		(105	)		(105	)		(465	)		(465	)		(1,389	)
Gain (loss) on extinguishment	$	(610	)	$	11,306		$	44,933		$	8,633		$	14,663		$	78,925

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28541-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21538-112644

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

FINANCIAL INSTRUMENTS (Tables)

9 Months Ended

Sep. 30, 2020

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.

	September 30, 2020				December 31, 2019
	Carrying Value, Net		Estimated fair value (Level 2)		Carrying Value, Net		Estimated fair value (Level 2)
	(In thousands)
2022 Senior Notes	$	233,050	$	169,684	$	298,314	$	266,750
2025 Senior Notes		352,016		204,758		494,985		382,708

PARTNERS' CAPITAL AND MEZZANINE CAPITAL (Tables)

9 Months Ended

Sep. 30, 2020

Equity [Abstract]

Schedule of partner units activity

A rollforward of the number of common units follows.

	Common Units
Units, December 31, 2019⁽¹⁾		45,318,866
Net units issued under the SMLP LTIP		1,028,654
Impact of GP Buy-In Transaction		(1,990,303	)
Preferred Unit Exchange		12,267,670
Units, September 30, 2020⁽¹⁾		56,624,887

Change in subsidiary

The following table shows the change in our Subsidiary Series A Preferred Unit balance from December 31, 2019 to September 30, 2020:

	September 30, 2020
	(in thousands)
Balance at December 31, 2019	$	27,450
New issuances		50,000
PIK distributions		3,784
Issuance costs		(1,290	)
Redemption accretion		5,856
Balance at September 30, 2020⁽¹⁾	$	85,800

⁽¹⁾ Amount is net of $3.9 million of issuance costs at September 30, 2020.

Details of cash distributions

Prior to the GP Buy-In Transaction, SMLP paid the following per-unit distributions during the three and nine month periods ended September 30 (all payments represent per-unit distributions based on the SMLP common units outstanding prior to the GP Buy-In Transaction):

	Three months ended September 30,				Nine months ended September 30,
	2020		2019		2020		2019
Per-unit distributions to unitholders	$	—	$	0.2875	$	0.125	$	1.1500

EARNINGS PER UNIT (Tables)

9 Months Ended

Sep. 30, 2020

Earnings Per Share [Abstract]

Schedule of earnings per limited partner unit

The following table details the components of EPU.

	Three months ended September 30,					Nine months ended September 30,
	2020		2019			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	$	25,629	$	(789	)	$	89,386	$	(11,130	)
Less:
Net income attributable to Series A Preferred Units		6,481		7,125			20,731		21,375
Net income attributable to Subsidiary Series A Preferred Units		7,298		—			9,640		—
Add:
Deemed capital contribution from Series A Preferred Unit Exchange Offer		54,945		—			54,945		—
Net income (loss) attributable to common limited partners	$	66,795	$	(7,914	)	$	113,960	$	(32,505	)

Denominator for basic and diluted EPU:
Weighted-average common units outstanding – basic⁽¹⁾		51,974		45,319			47,331		45,319
Effect of nonvested phantom units		1,676		—			1,451		—
Weighted-average common units outstanding – diluted		53,650		45,319			48,782		45,319

Net Income (Loss) per limited partner unit:
Common unit – basic	$	1.29	$	(0.17	)	$	2.41	$	(0.72	)
Common unit – diluted	$	1.25	$	(0.17	)	$	2.34	$	(0.72	)

Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU		4,031		176			3,353		70

SUPPLEMENTAL CASH FLOW INFORMATION (Tables)

9 Months Ended

Sep. 30, 2020

Supplemental Cash Flow Elements [Abstract]

Schedule of supplemental cash flow information

	Nine months ended September 30,
	2020		2019
	(In thousands)
Supplemental cash flow information:
Cash interest paid	$	62,441	$	66,435
Less capitalized interest		2,268		5,752
Interest paid (net of capitalized interest)	$	60,173	$	60,683

Cash paid for taxes	$	—	$	150

Noncash investing and financing activities:
Capital expenditures in trade accounts payable (period-end accruals)	$	10,233	$	22,166
Warrant issuance for GP Buy-In Transaction		2,300		—
Asset contribution to an equity method investment		—		23,643
Right-of-use assets relating to ASC Topic 842		2,964		5,448
Accretion of Subsidiary Series A Preferred Units		5,856		—

COMMITMENTS AND CONTINGENCIES (Tables)

9 Months Ended

Sep. 30, 2020

Commitments And Contingencies Disclosure [Abstract]

Schedule of accrued environmental remediation

A rollforward of the Partnership’s undiscounted accrued environmental remediation liabilities follows.

	Total
	(In thousands)
Accrued environmental remediation, January 1, 2020	$	4,651
Payments made		(1,095	)
Accrued environmental remediation, September 30, 2020	$	3,556

SEGMENT INFORMATION (Tables)

9 Months Ended

Sep. 30, 2020

Segment Reporting [Abstract]

Schedule of assets by reportable segment

Assets by reportable segment follow.

	September 30, 2020		December 31, 2019
	(In thousands)
Assets⁽¹⁾:
Utica Shale	$	208,090	$	206,368
Ohio Gathering		263,639		275,000
Williston Basin		443,506		452,152
DJ Basin		204,206		205,308
Permian Basin		167,707		185,708
Piceance Basin		596,148		631,140
Barnett Shale		349,254		350,638
Marcellus Shale		182,900		184,631
Total reportable segment assets		2,415,450		2,490,945
Corporate and Other		158,029		83,153
Total assets	$	2,573,479	$	2,574,098

⁽¹⁾

Reconciliation of net income to adjusted EBITDA

Segment adjusted EBITDA by reportable segment follows.

	Three months ended September 30,				Nine months ended September 30,
	2020		2019		2020		2019
	(In thousands)
Reportable segment adjusted EBITDA
Utica Shale	$	7,453	$	7,864	$	24,074	$	20,697
Ohio Gathering		7,129		10,435		22,582		29,584
Williston Basin		11,713		13,840		40,632		49,224
DJ Basin		4,766		6,554		15,016		12,043
Permian Basin		893		210		4,302		(996	)
Piceance Basin		21,503		24,044		66,794		74,627
Barnett Shale		7,205		10,901		24,475		33,483
Marcellus Shale		6,022		4,958		16,230		14,735
Total of reportable segments' measures of profit	$	66,684	$	78,806	$	214,105	$	233,397

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 follows.

	Three months ended September 30,						Nine months ended September 30,
	2020			2019			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	$	25,132		$	(10,431	)	$	78,862		$	(45,757	)
Add:
Corporate and Other expense		6,874			7,119			28,484			32,024
Interest expense		19,018			23,462			64,836			68,547
Gain on early extinguishment of debt		(24,690	)		—			(78,925	)		—
Depreciation and amortization⁽¹⁾		29,739			27,677			89,505			83,030
Proportional adjusted EBITDA for equity method investees		7,129			10,435			22,582			29,584
Adjustments related to MVC shortfall payments		2,292			3,534			(859	)		2,868
Adjustments related to capital reimbursement activity		(328	)		(145	)		(776	)		(1,906	)
Unit-based and noncash compensation		1,622			1,291			6,191			5,370
Gain on asset sales, net		(104	)		(347	)		(270	)		(1,595	)
Long-lived asset impairment		—			—			4,475			45,021
Goodwill impairment		—			16,211			—			16,211
Total of reportable segments' measures of profit	$	66,684		$	78,806		$	214,105		$	233,397

⁽¹⁾ Includes the amortization expense associated with our favorable gas gathering contracts as reported in other revenues.

ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
	May 28, 2020	Sep. 30, 2020	Dec. 31, 2019
Organization And Business Operations [Line Items]
Purchase agreement date		May 28, 2020
Common limited partner capital (shares)		56,624,887	45,318,866
Common Units
Organization And Business Operations [Line Items]
Number of common units purchased.	8,059,609
Common Units \| Energy Capital Partners
Organization And Business Operations [Line Items]
Common limited partner capital (shares)		5,915,827
Summit Midstream Partners Holdings L L C
Organization And Business Operations [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
Common units retire		16,630,112
Summit Investments
Organization And Business Operations [Line Items]
Cash paid to Acquire investment		$ 35.0
Summit Investments \| Common Units
Organization And Business Operations [Line Items]
Number of common units purchased.		10,000,000

REVENUE - Schedule of Estimated Revenue Expected to be Recognized and MVC Shortfall Payments (Details) - Gathering Services and Related Fees $ in Thousands	Sep. 30, 2020 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-10-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, Period	3 months
Revenue, remaining performance obligation	$ 29,678
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
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	$ 102,127
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01
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	$ 84,736
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2023-01-01
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	$ 66,693
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2024-01-01
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	$ 50,608
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2025-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, Period
Revenue, remaining performance obligation	$ 56,912

REVENUE - Schedule of Disaggregated Revenue by Geographic Area and Major Products and Services Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Total revenues	$ 90,153	$ 100,187	$ 287,063	$ 331,281
All Other Segments
Disaggregation Of Revenue [Line Items]
Total revenues	644	534	1,931	26,978
Reportable Segments
Disaggregation Of Revenue [Line Items]
Total revenues	89,509	99,653	285,132	304,303
Reportable Segments \| Utica Shale
Disaggregation Of Revenue [Line Items]
Total revenues	8,385	8,865	26,885	23,951
Reportable Segments \| Williston Basin
Disaggregation Of Revenue [Line Items]
Total revenues	19,035	21,118	68,612	77,440
Reportable Segments \| DJ Basin
Disaggregation Of Revenue [Line Items]
Total revenues	6,894	7,867	21,145	17,839
Reportable Segments \| Permian Basin
Disaggregation Of Revenue [Line Items]
Total revenues	7,566	4,885	21,635	12,545
Reportable Segments \| Piceance Basin
Disaggregation Of Revenue [Line Items]
Total revenues	28,337	33,111	85,313	101,995
Reportable Segments \| Barnett Shale
Disaggregation Of Revenue [Line Items]
Total revenues	12,421	17,820	42,508	52,452
Reportable Segments \| Marcellus Shale
Disaggregation Of Revenue [Line Items]
Total revenues	6,871	5,987	19,034	18,081
Gathering Services and Related Fees
Disaggregation Of Revenue [Line Items]
Total revenues	71,964	80,968	229,667	243,039
Gathering Services and Related Fees \| All Other Segments
Disaggregation Of Revenue [Line Items]
Total revenues	0	0	0	(2,045)
Gathering Services and Related Fees \| Reportable Segments
Disaggregation Of Revenue [Line Items]
Total revenues	71,964	80,968	229,667	245,084
Gathering Services and Related Fees \| Reportable Segments \| Utica Shale
Disaggregation Of Revenue [Line Items]
Total revenues	8,385	8,865	26,885	23,951
Gathering Services and Related Fees \| Reportable Segments \| Williston Basin
Disaggregation Of Revenue [Line Items]
Total revenues	10,941	16,685	47,145	58,076
Gathering Services and Related Fees \| Reportable Segments \| DJ Basin
Disaggregation Of Revenue [Line Items]
Total revenues	6,051	7,039	18,134	14,784
Gathering Services and Related Fees \| Reportable Segments \| Permian Basin
Disaggregation Of Revenue [Line Items]
Total revenues	2,595	986	7,617	1,938
Gathering Services and Related Fees \| Reportable Segments \| Piceance Basin
Disaggregation Of Revenue [Line Items]
Total revenues	26,576	30,120	79,987	92,515
Gathering Services and Related Fees \| Reportable Segments \| Barnett Shale
Disaggregation Of Revenue [Line Items]
Total revenues	10,545	11,286	30,865	35,739
Gathering Services and Related Fees \| Reportable Segments \| Marcellus Shale
Disaggregation Of Revenue [Line Items]
Total revenues	6,871	5,987	19,034	18,081
Natural Gas, NGLs and Condensate Sales
Disaggregation Of Revenue [Line Items]
Total revenues	10,783	12,219	35,246	68,438
Natural Gas, NGLs and Condensate Sales \| All Other Segments
Disaggregation Of Revenue [Line Items]
Total revenues	0	(110)	0	28,660
Natural Gas, NGLs and Condensate Sales \| Reportable Segments
Disaggregation Of Revenue [Line Items]
Total revenues	10,783	12,329	35,246	39,778
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	4,958	1,878	12,413	11,231
Natural Gas, NGLs and Condensate Sales \| Reportable Segments \| DJ Basin
Disaggregation Of Revenue [Line Items]
Total revenues	17	93	158	279
Natural Gas, NGLs and Condensate Sales \| Reportable Segments \| Permian Basin
Disaggregation Of Revenue [Line Items]
Total revenues	4,803	3,797	13,537	10,424
Natural Gas, NGLs and Condensate Sales \| Reportable Segments \| Piceance Basin
Disaggregation Of Revenue [Line Items]
Total revenues	528	1,733	1,932	6,139
Natural Gas, NGLs and Condensate Sales \| Reportable Segments \| Barnett Shale
Disaggregation Of Revenue [Line Items]
Total revenues	477	4,828	7,206	11,705
Natural Gas, NGLs and Condensate Sales \| Reportable Segments \| Marcellus Shale
Disaggregation Of Revenue [Line Items]
Total revenues	0	0	0	0
Other Revenues
Disaggregation Of Revenue [Line Items]
Total revenues	7,406	7,000	22,150	19,804
Other Revenues \| All Other Segments
Disaggregation Of Revenue [Line Items]
Total revenues	644	644	1,931	363
Other Revenues \| Reportable Segments
Disaggregation Of Revenue [Line Items]
Total revenues	6,762	6,356	20,219	19,441
Other Revenues \| Reportable Segments \| Utica Shale
Disaggregation Of Revenue [Line Items]
Total revenues	0	0	0	0
Other Revenues \| Reportable Segments \| Williston Basin
Disaggregation Of Revenue [Line Items]
Total revenues	3,136	2,555	9,054	8,133
Other Revenues \| Reportable Segments \| DJ Basin
Disaggregation Of Revenue [Line Items]
Total revenues	826	735	2,853	2,776
Other Revenues \| Reportable Segments \| Permian Basin
Disaggregation Of Revenue [Line Items]
Total revenues	168	102	481	183
Other Revenues \| Reportable Segments \| Piceance Basin
Disaggregation Of Revenue [Line Items]
Total revenues	1,233	1,258	3,394	3,341
Other Revenues \| Reportable Segments \| Barnett Shale
Disaggregation Of Revenue [Line Items]
Total revenues	1,399	1,706	4,437	5,008
Other Revenues \| Reportable Segments \| Marcellus Shale
Disaggregation Of Revenue [Line Items]
Total revenues	$ 0	$ 0	$ 0	$ 0

REVENUE - Schedule of Information about Contract Assets from Contracts with Customers (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Contract With Customer Asset And Liability [Abstract]
Contract assets, beginning of period	$ 3,902
Additions	16,442
Transfers out	(2,275)
Contract assets, end of period	$ 18,069

REVENUE - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
REVENUE - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Revenue From Contract With Customer [Line Items]
Receivables with customers	$ 53,800		$ 53,800		$ 90,400
Contract assets included in accounts receivable	18,069		18,069		$ 3,902
Gathering Services and Related Fees
Revenue From Contract With Customer [Line Items]
Contract liabilities, revenue	$ 2,400	$ 2,400	$ 7,100	$ 7,800

PROPERTY, PLANT, AND EQUIPMENT, NET - Schedule of Property, Plant, and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 2,346,262	$ 2,326,398
Less accumulated depreciation	(505,978)	(443,909)
Property, plant and equipment, net	1,840,284	1,882,489
Gathering and processing systems and related equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,197,087	2,182,950
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	78,146	78,716
Land and line fill
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	10,440	10,137
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 60,589	$ 54,595

PROPERTY, PLANT, AND EQUIPMENT, NET - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Property, Plant and Equipment [Line Items]
Asset impairment charges			$ 10.2
Rights-of-way
Property, Plant and Equipment [Line Items]
Asset impairment charges			0.5
DJ Basin
Property, Plant and Equipment [Line Items]
Asset impairment charges	$ 34.7	$ 3.6
Barnett Shale \| Fixed Assets
Property, Plant and Equipment [Line Items]
Asset impairment charges			$ 9.7

PROPERTY, PLANT, AND EQUIPMENT, NET - Schedule of Depreciation Expense and Capitalized Interest (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Property Plant And Equipment [Abstract]
Depreciation expense	$ 21,537	$ 19,474	$ 64,899	$ 58,160
Capitalized interest	$ 1,449	$ 1,391	$ 2,268	$ 5,752

GOODWILL - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
GOODWILL - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Goodwill [Line Items]
Goodwill impairment	$ 16,211	$ 0	$ 16,211
Mountaineer Midstream
Goodwill [Line Items]
Goodwill impairment	$ 16,200		$ 16,200

EQUITY METHOD INVESTMENTS - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Schedule Of Equity Method Investments [Line Items]
Additional cash investments	$ 12,400	$ 92,100
Double E
Schedule Of Equity Method Investments [Line Items]
Result of operations	$ 0	$ 0
OGC \| Principal Owner
Schedule Of Equity Method Investments [Line Items]
Percentage of ownership interest	38.20%	38.20%	38.50%

EQUITY METHOD INVESTMENTS - Rollforward of the Investment in Equity Method Investees (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019
Schedule Of Equity Method Investments [Line Items]
Investment in Ohio Gathering, September 30, 2020	$ 389,088	$ 389,088
September cash distributions		19,859	$ 28,008
Investment in Ohio Gathering (Books and records), August 31, 2020		309,728
OGC \| Summit Midstream Partners, LLC
Schedule Of Equity Method Investments [Line Items]
Investment in Ohio Gathering, September 30, 2020	263,639	$ 263,639
September cash distributions	3,870
Basis difference	218,757
Investment in Ohio Gathering (Books and records), August 31, 2020	$ 486,266

DEFERRED REVENUE - Rollforward of deferred revenue (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Movement in Deferred Revenue [Roll Forward]
Current deferred revenue, beginning balance	$ 13,493
Current deferred revenue, Additions	15,433
Current deferred revenue, Less revenue recognized	(11,099)
Current deferred revenue, ending balance	17,827
Noncurrent deferred revenue, beginning balance	38,709
Noncurrent deferred revenue, Additions	18,402
Noncurrent deferred revenue, Less reclassification to current deferred revenue	(15,356)
Noncurrent deferred revenue, ending balance	$ 41,755

DEBT - Components of Long-Term Debt (Details) - USD ($)
$ in Thousands

Sep. 30, 2020

Dec. 31, 2019

Summit Midstream Partners Holdings L L C

Long-term debt

$ 1,390,842

$ 1,622,279

Summit Midstream Partners Holdings L L C | Senior Secured Revolving Credit Facility Due May 2022

Total debt

1,546,042

1,627,825

Less: current portion

(155,200)

(5,546)

Long-term debt

1,390,842

1,622,279

Revolving credit facility

808,500

677,000

Summit Midstream Partners Holdings L L C | Senior Secured Term Loan Due March 2021

Revolving credit facility

Summit Midstream Partners Holdings L L C | Senior Notes Due August 2022

Less unamortized debt issuance costs

Unsecured notes

234,047

300,000

^[1]

(997)

(1,686)

Summit Midstream Partners Holdings L L C | Senior Secured Term Loan Due May 2022

Revolving credit facility

155,200

161,500

Less unamortized debt issuance costs

^[1]

(2,724)

(3,974)

Summit Midstream Partners Holdings L L C | Senior Notes Due April 2025

Less unamortized debt issuance costs

Unsecured notes

355,071

500,000

^[1]

$ (3,055)

$ (5,015)

[1]	Issuance costs are being amortized over the life of the SMPH Term Loan and the Senior Notes.

DEBT - Components of Long-Term Debt (Parenthetical) (Details) - Summit Midstream Partners Holdings L L C	Sep. 30, 2020	Dec. 31, 2019
Senior Secured Term Loan Due May 2022
Line of Credit Facility [Line Items]
Variable interest rate	7.00%	7.80%
Senior Secured Revolving Credit Facility Due May 2022
Line of Credit Facility [Line Items]
Variable interest rate	2.90%	4.55%
Senior Notes Due August 2022
Line of Credit Facility [Line Items]
Stated interest rate	5.50%	5.50%
Senior Notes Due April 2025
Line of Credit Facility [Line Items]
Stated interest rate	5.75%	5.75%
Senior Secured Term Loan Due March 2021
Line of Credit Facility [Line Items]
Stated interest rate	8.00%	8.00%

DEBT - Revolving Credit Facility (Narrative) (Details)	9 Months Ended
DEBT - Revolving Credit Facility (Narrative) (Details)	Sep. 30, 2020 USD ($)
Line of Credit Facility [Line Items]
Line of credit facility, outstanding amount	$ 4,100,000
Current borrowing capacity	172,000,000.0
Debt defaults	0
Revolving credit facility
Line of Credit Facility [Line Items]
Borrowing capacity	$ 1,250,000,000
Revolving credit facility maturity date	2022-05
Accordion feature	$ 250,000,000.0
Commitment fee on unused portion of the facility	0.50%
Interest rate at period end	2.90%
Unused portion under the facility	$ 437,400,000
Revolving credit facility \| LIBOR
Line of Credit Facility [Line Items]
Applicable margin	2.75%

DEBT - ECP Loans (Narrative) (Details) $ in Millions	May 28, 2020 USD ($)
Debt Instrument [Line Items]
Line of credit facility description	(i) a Term Loan Credit Agreement (the “ECP NewCo Term Loan Credit Agreement”), with SMP TopCo, LLC, a Delaware limited liability company and affiliate of ECP (“ECP NewCo”), as lender and administrative agent, and Mizuho Bank (USA) (“Mizuho”), as collateral agent, in a principal amount of $28.2 million (the “ECP NewCo Loan”), and (ii) a Term Loan Credit Agreement (the “ECP Holdings Term Loan Credit Agreement” and together with the ECP NewCo Term Loan Credit Agreement, the “ECP Term Loan Credit Agreements”), with ECP Holdings, as lender, and ECP NewCo, as administrative agent and Mizuho, as collateral agent, in a principal amount of $6.8 million (the “ECP Holdings Loan” and together with the ECP NewCo Loan, the “ECP Loans”). The ECP Loans were set to mature on March 31, 2021 and bore interest at a rate of 8.00% per annum, with the interest payment due at maturity of the ECP Loans. With borrowings under the Partnership’s Revolving Credit Facility, the Partnership fully repaid all amounts outstanding under the ECP Loans ($35 million of principal and $0.6 million of accrued interest) on August 7, 2020.
ECP NewCo Term Loan Credit Agreement [Member]
Debt Instrument [Line Items]
Debt instrument principal amount	$ 28.2
ECP Term Loan Credit Agreements [Member]
Debt Instrument [Line Items]
Debt instrument principal amount	$ 6.8
Maturity date	Mar. 31, 2021
Stated interest rate	8.00%
Repayments of loans	$ 35.0
Accrued interest on loan	$ 0.6

DEBT - Term Loan (Narrative) (Details) - Term Loan B [Member] - USD ($) $ in Millions		3 Months Ended	9 Months Ended
	Apr. 17, 2020	Sep. 30, 2020	Sep. 30, 2020
Debt Instrument [Line Items]
Derivative, notional amount	$ 125.0
Derivative, beginning date	Apr. 30, 2020
Derivative, maturity date	Apr. 30, 2022
Unsettled gain		$ 0.1	$ 0.1
Debt issuance costs incurred			$ 0.2
LIBOR
Debt Instrument [Line Items]
Derivative, fixed interest rate	1.00%

DEBT - Liability Management Transactions (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
	Sep. 29, 2020	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019
Debt Instrument [Line Items]
Gains on extinguishment of debt		$ 24,690	$ 78,925	$ 0
Liability Management Transactions \| Open Market Repurchases
Debt Instrument [Line Items]
Gains on extinguishment of debt			56,200
Liability Management Transactions \| Tender Offers
Debt Instrument [Line Items]
Gains on extinguishment of debt			23,300
Liability Management Transactions \| SMPH Term Loan Restructuring
Debt Instrument [Line Items]
Term Loan result in consensual debt discharge of full amount owed under Term Loan exchange	$ 155,200
Cash payments to creditors	26,500
Amount of common units pledged as collateral	34,600
Cash payment on the Deferred Purchase Price Obligation	$ 26,500
Liability Management Transactions \| Senior Notes Due 2022 And 2025
Debt Instrument [Line Items]
Early extinguishment of debt		210,800	210,800
Liability Management Transactions \| Senior Notes Due 2022 \| Open Market Repurchases
Debt Instrument [Line Items]
Senior Notes repurchased		32,400	32,400
Cash consideration paid		82,900	82,900
Liability Management Transactions \| Senior Notes Due 2022 \| Tender Offers
Debt Instrument [Line Items]
Senior Notes repurchased		33,500	33,500
Cash consideration paid		48,700	48,700
Liability Management Transactions \| Senior Notes Due April 2025 \| Open Market Repurchases
Debt Instrument [Line Items]
Senior Notes repurchased		106,200	106,200
Cash consideration paid		82,900	82,900
Liability Management Transactions \| Senior Notes Due April 2025 \| Tender Offers
Debt Instrument [Line Items]
Senior Notes repurchased		38,700	38,700
Cash consideration paid		$ 48,700	$ 48,700

DEBT - Gain on Extinguishment of Debt (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019
Debt Instrument [Line Items]
Gains on extinguishment of debt	$ 24,690	$ 78,925	$ 0
Liability Management Transactions \| Open Market Repurchases and Tender Offer Repurchase
Debt Instrument [Line Items]
Gains on extinguishment of debt		$ 78,900

DEBT - Schedule of Extinguishment of Debt (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019
Extinguishment Of Debt [Line Items]
Gain on repurchases of Senior Notes		$ 82,259
Debt issue costs		(1,945)
Transaction cost		(1,389)
Gain (loss) on extinguishment	$ 24,690	78,925	$ 0
ECP Loan Repayment
Extinguishment Of Debt [Line Items]
Debt issue costs		(361)
Transaction cost		(249)
Gain (loss) on extinguishment		(610)
Senior Notes Due 2022 \| Open Market Repurchases
Extinguishment Of Debt [Line Items]
Gain on repurchases of Senior Notes		11,554
Debt issue costs		(143)
Transaction cost		(105)
Gain (loss) on extinguishment		11,306
Senior Notes Due 2022 \| Tender Offers
Extinguishment Of Debt [Line Items]
Gain on repurchases of Senior Notes		9,223
Debt issue costs		(125)
Transaction cost		(465)
Gain (loss) on extinguishment		8,633
Senior Notes Due 2025 \| Open Market Repurchases
Extinguishment Of Debt [Line Items]
Gain on repurchases of Senior Notes		46,003
Debt issue costs		(965)
Transaction cost		(105)
Gain (loss) on extinguishment		44,933
Senior Notes Due 2025 \| Tender Offers
Extinguishment Of Debt [Line Items]
Gain on repurchases of Senior Notes		15,479
Debt issue costs		(351)
Transaction cost		(465)
Gain (loss) on extinguishment		$ 14,663

FINANCIAL INSTRUMENTS - Fair value of Debt Instruments (Details) - Summit Holdings - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
2022 Senior Notes \| Carrying Value, Net
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	$ 233,050	$ 298,314
2022 Senior Notes \| Fair Value \| Estimated fair value (Level 2)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	169,684	266,750
2025 Senior Notes \| Carrying Value, Net
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	352,016	494,985
2025 Senior Notes \| Fair Value \| Estimated fair value (Level 2)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	$ 204,758	$ 382,708

PARTNERS' CAPITAL AND MEZZANINE CAPITAL - Partners' Capital and Schedule of Units (Details) - Common Units	9 Months Ended
	Sep. 30, 2020 shares
Rollforwards of the number of partner units
Units, beginning balance (in shares)	45,318,866
Net units issued under the SMLP LTIP (in shares)	1,028,654
Impact of GP Buy-In Transaction	(1,990,303)
Preferred Unit Exchange	12,267,670
Units, ending balance (in shares)	56,624,887

PARTNERS' CAPITAL AND MEZZANINE CAPITAL - Partners' Capital and Schedule of Units (Parenthetical) (Details) - shares	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Partners Capital [Line Items]
Common limited partner capital (in shares), issued	56,624,887	45,318,866
Common Units
Partners Capital [Line Items]
Partners capital account units	56,600,000	45,300,000
Common limited partner capital (in shares), issued	1,000,000.0
Common Units \| Preferred Unit Exchange
Partners Capital [Line Items]
Exchange Offer	12,300,000
Common Units \| Term Loan B [Member]
Partners Capital [Line Items]
Common units pledged as collateral	34,600,000
Common units not pledged as collateral	10,700,000
Common Units \| Energy Capital Partners
Partners Capital [Line Items]
Common units owned by ECP	5,900,000
Previously Reported \| Common Units
Partners Capital [Line Items]
Partners capital account units	94,500,000

PARTNERS' CAPITAL AND MEZZANINE CAPITAL - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended
	Jul. 28, 2020	May 28, 2020	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2017
Partners Capital [Line Items]
Preferred units issued				237,184	237,184		300,000
Common limited partner capital (in shares), outstanding				56,624,887	56,624,887		45,318,866
Series A Preferred Units
Partners Capital [Line Items]
Preferred units issued	62,816			53,784	53,784		83,842	300,000
Interest in partnership per unit				$ 1,000	$ 1,000			$ 1,000
Common limited partner capital (in shares), outstanding				237,184	237,184
Proceeds from issuance of common limited partners units					$ 48,700
Redemption amount				$ 104,800	$ 104,800
Series A Preferred Units \| Paid-in-Kind Distributions
Partners Capital [Line Items]
Pro-rated issuance of preferred units				45	1,442
Pro-rated distribution of preferred units				$ 32.1133	$ 17.5099
Pro-rated distribution of preferred units						$ 70
Pro-rated issuance of preferred units related to undrawn commitment					38
Common Units
Partners Capital [Line Items]
Number of common units purchased.		8,059,609
General partner units converted	12,267,670
Exercise price of Warrants		$ 1.023
Valuation of warrants		$ 2,300		$ 1,500	$ 1,500
Warrant or right, reason for issuance, description					Upon exercise of the ECP Warrants, each of ECP NewCo and ECP Holdings may receive, at its election: (i) a number of SMLP common units equal to the number of SMLP common units for which the ECP Warrants are being exercised, if exercising the ECP Warrants by cash payment of the exercise price; (ii) a number of SMLP common units equal to the product of the number of common units being exercised multiplied by (a) the difference between the average of the daily volume-weighted average price (“VWAP”) of the SMLP common units on the New York Stock Exchange (the “NYSE”) on each of the three trading days prior to the delivery of the notice of exercise (the “VWAP Average”) and the exercise price (the “VWAP Difference”), divided by (b) the VWAP Average; and/or (iii) an amount in cash, to the extent that the Partnership’s leverage ratio would be at least 0.5x less than the maximum applicable ratio set forth in the Revolving Credit Facility, equal to the product of (a) the number of SMLP common units exercised and (b) the VWAP Difference, subject to certain adjustments under the ECP Warrants.
Common Units \| Summit Midstream Partners, LP
Partners Capital [Line Items]
General partner units converted			8,750,000
Common Units \| ECP Holdings Warrant
Partners Capital [Line Items]
Number of common units purchased.		1,940,391
Common Units \| Energy Capital Partners
Partners Capital [Line Items]
Warrants exercisable date		May 28, 2023
Common Units \| Maximum
Partners Capital [Line Items]
Exercise price of Warrants		$ 2.00
Common units, issued		10,000,000
General Partner \| Summit Midstream Partners, LP
Partners Capital [Line Items]
General partner interest			2.00%
General Partner \| Common Units
Partners Capital [Line Items]
Cash paid to Acquire investment					$ 35,000
Number of common units purchased.					10,000,000
Advisory fees and other direct costs					$ 6,800
Fair value of warrants					$ 2,300

PARTNERS' CAPITAL AND MEZZANINE CAPITAL- Change in Subsidiary (Details)

9 Months Ended

Sep. 30, 2020

USD ($)

Partners Capital [Line Items]

Issuance costs

$ (3,900,000)

Series A Preferred Units

Partners Capital [Line Items]

Balance

$ 27,450,000

New issuances | shares

50,000

PIK distributions | shares

3,784

Issuance costs

$ (1,290,000)

Redemption accretion

5,856,000

Balance

$ 85,800,000

^[1]

[1]	⁽¹⁾ Amount is net of $3.9 million of issuance costs at September 30, 2020

PARTNERS' CAPITAL AND MEZZANINE CAPITAL - Parenthetical (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($)
Equity [Abstract]
Issuance costs	$ 3.9

PARTNERS' CAPITAL AND MEZZANINE CAPITAL - Cash Distributions Paid and Declared (Details) - $ / shares	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Equity [Abstract]
Per-unit annual distributions to unitholders (in dollars per unit)	$ 0.2875	$ 0.125	$ 1.1500

EARNINGS PER UNIT (Details) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

9 Months Ended

Sep. 30, 2020

Sep. 30, 2019

Sep. 30, 2020

Sep. 30, 2019

Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]

$ 25,629

$ (789)

$ 89,386

$ (11,130)

Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]

$ 54,945

Phantom Units

Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU

4,031

176

3,353

Limited Partner Interest Before Subordinated Units Converted To Common Units

Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]

Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]

$ 25,629

$ (789)

$ 89,386

$ (11,130)

Series A Preferred Units

6,481

7,125

20,731

21,375

Series A Preferred Units | Subsidiaries

54,945

Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]

Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]

7,298

9,640

Common units