Summit Midstream Partners (SMLP) 10-K 27 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 16, 2017	Jun. 30, 2016
Entity Information [Line Items]
Entity Registrant Name	Summit Midstream Partners, LP
Entity Central Index Key	1,549,922
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 700,056,455
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
General Partner Units
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		1,471,187
Common units
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		72,111,121

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 7,428	$ 21,793	$ 27,811
Accounts receivable	97,364	89,581
Other current assets	4,309	3,573
Total current assets	109,101	114,947
Property, plant and equipment, net	1,853,671	1,812,783
Intangible assets, net	421,452	461,310
Goodwill	16,211	16,211	265,062
Investment in equity method investees	707,415	751,168
Other noncurrent assets	7,329	8,253
Total assets	3,115,179	3,164,672	3,242,462
Current liabilities:
Trade accounts payable	16,251	40,808
Accrued expenses	11,389	6,776
Due to affiliate	258	1,149
Deferred revenue	0	677	2,377
Ad valorem taxes payable	10,588	10,271
Accrued interest	17,483	17,483
Accrued environmental remediation	4,301	7,900
Other current liabilities	11,471	6,521
Total current liabilities	71,741	91,585
Long-term debt	1,240,301	1,267,270
Deferred Purchase Price Obligation	563,281	0
Deferred revenue	57,465	45,486	55,239
Noncurrent accrued environmental remediation	5,152	5,764
Other noncurrent liabilities	7,566	7,268
Total liabilities	1,945,506	1,417,373
Commitments and contingencies (Note 15)
Common limited partner capital (72,111 units issued and outstanding at December 31, 2016 and 42,063 units issued and outstanding at December 31, 2015)	1,129,132	744,977
Subordinated limited partner capital (0 units issued and outstanding at December 31, 2016 and 24,410 units issued and outstanding at December 31, 2015)	0	213,631
General partner interests (1,471 units issued and outstanding at December 31, 2016 and 1,355 units issued and outstanding at December 31, 2015)	29,294	25,634
Noncontrolling interest	11,247	0
Summit Investments' equity in contributed subsidiaries	0	763,057
Total partners' capital	1,169,673	1,747,299	$ 1,830,678
Total liabilities and partners' capital	$ 3,115,179	$ 3,164,672

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares shares in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Common limited partner capital (in shares)	72,111	42,063
Common limited partner capital (in shares)	72,111	42,063
Subordinated limited partner capital (in shares)	0	24,410
Subordinated limited partner capital (in shares)	0	24,410
General partner interests (in shares)	1,471	1,355
General partner interests (in shares)	1,471	1,355

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Gathering services and related fees	$ 345,961	$ 337,819	$ 267,478
Natural gas, NGLs and condensate sales	35,833	42,079	97,094
Other revenues	20,568	20,659	22,597
Total revenues	402,362	400,557	387,169
Costs and expenses:
Cost of natural gas and NGLs	27,421	31,398	72,415
Operation and maintenance	95,334	94,986	94,869
General and administrative	52,410	45,108	43,281
Depreciation and amortization	112,239	105,117	90,878
Transaction costs	1,321	1,342	2,985
Environmental remediation	0	21,800	5,000
Loss (gain) on asset sales, net	93	(172)	442
Long-lived asset impairment	1,764	9,305	5,505
Goodwill impairment	0	248,851	54,199
Total costs and expenses	290,582	557,735	369,574
Other income	116	2	1,189
Interest expense	(63,810)	(59,092)	(48,586)
Deferred Purchase Price Obligation expense	(55,854)	0	0
Loss before income taxes and loss from equity method investees	(7,768)	(216,268)	(29,802)
Income tax (expense) benefit	(75)	603	(854)
Loss from equity method investees	(30,344)	(6,563)	(16,712)
Net loss	(38,187)	(222,228)	(47,368)
Net income (loss) attributable to Summit Investments	2,745	(30,016)	(23,376)
Net loss attributable to noncontrolling interest	(14)	0	0
Net loss attributable to SMLP	(40,918)	(192,212)	(23,992)
Less net loss and IDRs attributable to General Partner	7,261	3,398	3,125
Net loss attributable to limited partners	(48,179)	(195,610)	(27,117)
Common units
Costs and expenses:
Net loss attributable to limited partners	$ (48,179)	$ (125,437)	$ (16,324)
Loss per limited partner unit:
Basic (in dollars per share)	$ (0.71)	$ (3.20)	$ (0.49)
Diluted (in dollars per share)	$ (0.71)	$ (3.20)	$ (0.49)
Weighted-average limited partner units outstanding:
Basic (shares)	68,264	39,217	33,311
Diluted (shares)	68,264	39,217	33,311
Subordinated Units
Costs and expenses:
Net loss attributable to limited partners		$ (70,173)	$ (10,793)
Loss per limited partner unit:
Basic (in dollars per share)		$ (2.88)	$ (0.44)
Diluted (in dollars per share)		$ (2.88)	$ (0.44)
Weighted-average limited partner units outstanding:
Basic (shares)		24,410	24,410
Diluted (shares)		24,410	24,410

CONSOLIDATED STATEMENTS OF PART

CONSOLIDATED STATEMENTS OF PARTNERS' CAPITAL - USD ($) $ in Thousands	Total	Class B membership interest	Noncontrolling interest	Summit Investments' equity in contributed subsidiaries	Summit Investments' equity in contributed subsidiariesClass B membership interest	Common	CommonClass B membership interest	Limited partners, Subordinated	General Partner
Beginning balance at Dec. 31, 2013	$ 1,395,806			$ 426,663		$ 566,532		$ 379,287	$ 23,324
Increase (Decrease) in Partners' Capital [Roll Forward]
Net (loss) income	(47,368)			(23,376)		(15,948)		(11,169)	3,125
Distributions to unitholders	(122,224)					(67,658)		(49,796)	(4,770)
Compensation	4,696	$ 1,145			$ 1,145	4,696
Tax withholdings on vested SMLP LTIP awards	(656)					(656)
Issuance of common units, net of offering costs	197,806					197,806
Contribution from General Partner	4,235								4,235
Purchase of Red Rock Gathering	(307,941)			(307,941)
Excess of purchase price over acquired carrying value of Red Rock Gathering				66,124		(37,910)		(26,891)	(1,323)
Assets contributed to Red Rock Gathering from Summit Investments	4,233					2,426		1,722	85
Cash advance from Summit Investments to contributed subsidiaries, net	674,383			674,383
Expenses paid by Summit Investments on behalf of contributed subsidiaries	24,884			24,884
Capitalized interest allocated to contributed subsidiaries from Summit Investments	1,310			1,310
Capital expenditures paid by Summit Investments on behalf of contributed subsidiaries	597			597
Repurchase of SMLP LTIP units	(228)					(228)
Excess of acquired carrying value over consideration paid for Polar and Divide	0
Distribution of debt related to Carve-Out Financial Statements of Summit Investments	0
Ending balance at Dec. 31, 2014	1,830,678			863,789		649,060		293,153	24,676
Increase (Decrease) in Partners' Capital [Roll Forward]
Net (loss) income	(222,228)			(30,016)		(123,817)		(71,793)	3,398
Distributions to unitholders	(152,074)					(86,880)		(55,410)	(9,784)
Compensation	6,174	843			843	6,174
Tax withholdings on vested SMLP LTIP awards	(1,616)					(1,616)
Issuance of common units, net of offering costs	221,977					221,977
Contribution from General Partner	4,737								4,737
Purchase of Red Rock Gathering	(285,677)			(285,677)
Assets contributed to Red Rock Gathering from Summit Investments	0
Cash advance from Summit Investments to contributed subsidiaries, net	320,527			320,527
Expenses paid by Summit Investments on behalf of contributed subsidiaries	22,879			22,879
Capitalized interest allocated to contributed subsidiaries from Summit Investments	1,079			1,079
Capital expenditures paid by Summit Investments on behalf of contributed subsidiaries	0
Excess of acquired carrying value over consideration paid for Polar and Divide	0			(130,367)		80,079		47,681	2,607
Distribution of debt related to Carve-Out Financial Statements of Summit Investments	0
Ending balance at Dec. 31, 2015	1,747,299		$ 0	763,057		744,977		213,631	25,634
Increase (Decrease) in Partners' Capital [Roll Forward]
Net (loss) income	(38,187)		(14)	2,745		(49,219)		1,040	7,261
Distributions to unitholders	(167,504)					(142,214)		(14,034)	(11,256)
Compensation	7,550	$ 435			$ 130	7,550	$ 305
Tax withholdings on vested SMLP LTIP awards	(1,181)					(1,181)
Issuance of common units, net of offering costs	125,233					125,233
Contribution from General Partner	2,702								2,702
Purchase of Red Rock Gathering	(866,858)			(866,858)
Assets contributed to Red Rock Gathering from Summit Investments	0
Cash advance from Summit Investments to contributed subsidiaries, net	12,214			12,214
Expenses paid by Summit Investments on behalf of contributed subsidiaries	4,821			4,821
Capitalized interest allocated to contributed subsidiaries from Summit Investments	223			223
Capital expenditures paid by Summit Investments on behalf of contributed subsidiaries	0
Excess of acquired carrying value over consideration paid for Polar and Divide	247,997			(247,997)		243,044			4,953
Subordinated units conversion						200,637		(200,637)
Establishment of noncontrolling interest			11,261	(11,261)
Distribution of debt related to Carve-Out Financial Statements of Summit Investments	342,926			342,926
Ending balance at Dec. 31, 2016	$ 1,169,673		$ 11,247	$ 0		$ 1,129,132		$ 0	$ 29,294

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net (loss) income	$ (38,187)	$ (222,228)	$ (47,368)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	112,661	105,903	91,822
Amortization of debt issuance costs	3,976	4,309	3,836
Deferred Purchase Price Obligation expense	55,854	0	0
Unit-based and noncash compensation	7,985	7,017	5,841
Loss from equity method investees	30,344	6,563	16,712
Distributions from equity method investees	44,991	34,641	2,992
Loss (gain) on asset sales, net	93	(172)	442
Long-lived asset impairment	1,764	9,305	5,505
Goodwill impairment	0	248,851	54,199
Write-off of debt issuance costs	0	727	1,554
Purchase accounting adjustment	0	0	(1,185)
Changes in operating assets and liabilities:
Accounts receivable	(7,783)	3,328	(21,503)
Insurance receivable	0	25,000	(25,000)
Trade accounts payable	2,001	(1,450)	(420)
Accrued expenses	4,613	(1,967)	509
Due to affiliate	(891)	1,377	(883)
Change in deferred revenue	11,302	(11,453)	26,378
Ad valorem taxes payable	317	1,092	804
Accrued interest	0	(1,375)	6,714
Accrued environmental remediation, net	(4,211)	(16,336)	30,000
Other, net	5,666	(1,757)	2,004
Net cash provided by operating activities	230,495	191,375	152,953
Cash flows from investing activities:
Capital expenditures	(142,719)	(272,225)	(343,380)
Initial contribution to Ohio Gathering	0	0	(8,360)
Acquisition of Ohio Gathering Option	0	0	(190,000)
Option Exercise	0	0	(382,385)
Contributions to equity method investees	(31,582)	(86,200)	(145,131)
Acquisition of gathering systems	0	0	(10,872)
Acquisitions of gathering systems from affiliate, net of acquired cash	(359,431)	(288,618)	(305,000)
Other, net	(394)	323	325
Net cash used in investing activities	(534,126)	(646,720)	(1,384,803)
Cash flows from financing activities:
Distributions to unitholders	(167,504)	(152,074)	(122,224)
Borrowings under Revolving Credit Facility	520,300	367,000	294,295
Repayments under Revolving Credit Facility	(204,300)	(151,000)	(430,295)
Borrowings under term loan	0	0	400,000
Repayments under term loan	0	(182,500)	(100,000)
Debt issuance costs	(3,032)	(412)	(8,323)
Proceeds from issuance of common units, net	125,233	221,977	197,806
Contribution from General Partner	2,702	4,737	4,235
Cash advance (to) from Summit Investments (from) to contributed subsidiaries, net	12,214	320,527	674,383
Expenses paid by Summit Investments on behalf of contributed subsidiaries	4,821	22,879	24,884
Issuance of senior notes	0	0	300,000
Repurchase of equity-based compensation awards	0	0	(228)
Other, net	(1,168)	(1,807)	(656)
Net cash provided by financing activities	289,266	449,327	1,233,877
Net change in cash and cash equivalents	(14,365)	(6,018)	2,027
Cash and cash equivalents, beginning of period	21,793	27,811	25,784
Cash and cash equivalents, end of period	7,428	21,793	27,811
Supplemental cash flow disclosures:
Cash interest paid	63,000	59,302	38,453
Less capitalized interest	3,709	3,372	4,646
Interest paid (net of capitalized interest)	59,291	55,930	33,807
Cash paid for taxes	0	0	0
Noncash investing and financing activities:
Capital expenditures in trade accounts payable (period-end accruals)	8,422	34,977	31,110
Issuance of Deferred Purchase Price Obligation to affiliate to partially fund the 2016 Drop Down	507,427	0	0
Excess of acquired carrying value over consideration paid and recognized for 2016 Drop Down Assets	247,997	0	0
Distribution of debt related to Carve-Out Financial Statements of Summit Investments	342,926	0	0
Excess of acquired carrying value over consideration paid for Polar and Divide	0	130,367	0
Capitalized interest allocated to contributed subsidiaries from Summit Investments	223	1,079	1,310
Capital expenditures paid by Summit Investments on behalf of contributed subsidiaries	0	0	597
Excess of consideration paid over acquired carrying value of Red Rock Gathering	0	0	(66,124)
Assets contributed to Red Rock Gathering from Summit Investments	$ 0	$ 0	$ 4,233

ORGANIZATION, BUSINESS OPERATIO

ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION	ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION Organization. SMLP, a Delaware limited partnership, was formed in May 2012 and began operations in October 2012 in connection with its IPO of common limited partner units. SMLP is a growth-oriented limited partnership focused on developing, owning and operating midstream energy infrastructure assets that are strategically located in the core producing areas of 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. The General Partner, a Delaware limited liability company, manages our operations and activities. Summit Investments, a Delaware limited liability company, is the ultimate owner of our General Partner and has the right to appoint the entire Board of Directors of our General Partner. Summit Investments is controlled by Energy Capital Partners. In addition to its approximate 2% general partner interest in SMLP (including the IDRs) in respect of SMLP, Summit Investments has indirect ownership interests in our common units. As of December 31, 2016 , Summit Investments beneficially owned 29,854,581 SMLP common units. Neither SMLP nor its subsidiaries have any employees. All of the personnel that conduct our business are employed by Summit Investments, but these individuals are sometimes referred to as our employees. Effective with the completion of its IPO, SMLP had a 100% ownership interest in Summit Holdings, which had a 100% ownership interest in both DFW Midstream and Grand River. In February 2013, Summit Investments acquired all of the outstanding membership interests of Bear Tracker Energy, LLC and subsequently renamed it Meadowlark Midstream. In June 2013, the Partnership acquired all of the membership interests of Bison Midstream from a subsidiary of Summit Investments (the "Bison Drop Down"). As such, the Bison Drop Down was determined to be a transaction among entities under common control. The net assets that comprise Bison Midstream were carved out from Meadowlark Midstream in connection with the Bison Drop Down. Common control of Bison Midstream began in February 2013. In June 2013, Mountaineer Midstream, LLC, a newly formed, wholly owned subsidiary of the Partnership, acquired natural gas gathering pipeline and compression assets from an affiliate of MarkWest Energy Partners, L.P. In December 2013, Mountaineer Midstream, LLC was merged into DFW Midstream. In March 2014, the Partnership acquired all of the membership interests of Red Rock Gathering from a subsidiary of Summit Investments (the "Red Rock Drop Down"). As such, the Red Rock Drop Down was determined to be a transaction among entities under common control. Common control of Red Rock Gathering began in October 2012. Concurrent with the closing of the Red Rock Drop Down, SMLP contributed its interest in Red Rock Gathering to Grand River. In May 2015, the Partnership acquired all of the membership interests of Polar Midstream and Epping from a subsidiary of Summit Investments (the "Polar and Divide Drop Down"). As such, the Polar and Divide Drop Down was determined to be a transaction among entities under common control. Polar Midstream's net assets were carved out of Meadowlark Midstream immediately prior to the Polar and Divide Drop Down. Concurrent with the closing of the Polar and Divide Drop Down, Epping became a wholly owned subsidiary of Polar Midstream and SMLP contributed Polar Midstream (including Epping) to Bison Midstream. Common control began in (i) February 2013 for Polar Midstream and (ii) April 2014 for Epping. In February 2016, the Partnership and SMP Holdings, a wholly owned subsidiary of Summit Investments, entered into a contribution agreement (the "Contribution Agreement") pursuant to which SMP Holdings agreed to contribute to the Partnership substantially all of its limited partner interest in OpCo, a Delaware limited partnership that owns (i) 100% of the issued and outstanding membership interests of Summit Utica, Meadowlark Midstream and Tioga Midstream and collectively with Summit Utica and Meadowlark Midstream, the "Contributed Entities"), each a limited liability company and (ii) a 40% ownership interest in each of OGC and OCC (collectively with OpCo and the Contributed Entities, the “2016 Drop Down Assets”)(the “2016 Drop Down”). The 2016 Drop Down closed in March 2016; concurrent therewith, a subsidiary of Summit Investments retained a 1% noncontrolling interest in OpCo, which is managed by OpCo GP, a Delaware limited liability company and a wholly owned subsidiary of Summit Holdings. Business Operations. We provide natural gas gathering, treating and processing services as well as crude oil and produced water gathering services pursuant to primarily long-term and fee-based agreements with our customers. Our results are driven primarily by the volumes of natural gas that we gather, treat, compress and process as well as by the volumes of crude oil and produced water that we gather. We are the owner-operator of or have significant ownership interests in the following gathering systems: • Ohio Gathering, a natural gas gathering system and a condensate stabilization facility operating in the Appalachian Basin, which includes the Utica and Point Pleasant shale formations in southeastern Ohio; • Summit Utica, a natural gas gathering system operating in the Appalachian Basin, which includes the Utica and Point Pleasant shale formations in southeastern Ohio; • Bison Midstream, an associated natural gas gathering system operating in the Williston Basin, which includes the Bakken and Three Forks shale formations in northwestern North Dakota; • Polar and Divide, crude oil and produced water gathering systems and transmission pipelines located in the Williston Basin, which includes the Bakken and Three Forks shale formations in northwestern North Dakota; • Tioga Midstream, crude oil, produced water and associated natural gas gathering systems, operating in the Williston Basin, which includes the Bakken and Three Forks shale formations in northwestern North Dakota; • Grand River, a natural gas gathering and processing system located in the Piceance Basin, which includes the Mesaverde formation and the Mancos and Niobrara shale formations in western Colorado and eastern Utah; • Niobrara G&P, an associated natural gas gathering and processing system operating in the DJ Basin, which includes the Niobrara and Codell shale formations in northeastern Colorado; • DFW Midstream, a natural gas gathering system operating in the Fort Worth Basin, which includes the Barnett Shale formation in north-central Texas; and • Mountaineer Midstream, a natural gas gathering system operating in the Appalachian Basin, which includes the Marcellus Shale formation in northern West Virginia. Meadowlark Midstream is the legal entity which owns (i) certain crude oil and produced water gathering pipelines, which are managed and reported as part of the Polar and Divide system subsequent to the 2016 Drop Down and (ii) Niobrara G&P, which is managed and reported as part of the Grand River system subsequent to the 2016 Drop Down. Presentation and Consolidation. We prepare our consolidated financial statements in accordance with GAAP as established by the FASB. We make estimates and assumptions that affect the reported amounts of assets and liabilities at the balance sheet dates, including fair value measurements, the reported amounts of revenue and expense and the disclosure of contingencies. Although management believes these estimates are reasonable, actual results could differ from its estimates. The consolidated financial statements include the assets, liabilities and results of operations of SMLP and its wholly owned subsidiaries. All intercompany transactions among the consolidated entities have been eliminated in consolidation. For the purposes of the consolidated financial statements, SMLP's results of operations reflect the results of operations of: (i) Bison Midstream, Polar and Divide, Grand River, Niobrara G&P, DFW Midstream and Mountaineer Midstream for all periods presented, (ii) Ohio Gathering since January 2014, (iii) Tioga Midstream since April 2014 and (iv) Summit Utica since December 2014. The financial position, results of operations and cash flows of Polar and Divide and Niobrara G&P included herein have been derived from the accounting records of Meadowlark Midstream on a carve-out basis (see Note 2). The carve-out allocations and estimates were based on methodologies that management believes are reasonable. The carve-out results reflected herein, however, may not reflect what these entities' financial position, results of operations or cash flows would have been if any had been a stand-alone company. SMLP recognized its drop down acquisitions at Summit Investments' historical cost because the acquisitions were executed by entities under common control. The excess of Summit Investments' net investment over the consideration paid and recognized for a contributed subsidiary is recognized as an addition to partners' capital, while the excess of purchase price paid and recognized over net investment is recognized as a reduction to partners' capital. Due to the common control aspect, we account for drop down transactions on an “as-if pooled” basis for the periods during which common control existed. Reclassifications. In the first quarter of 2016, we adopted ASU No. 2015-03 Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs ("ASU 2015-03"). As a result, these consolidated financial statements reflect the retrospective reclassification of $9.2 million of debt issuance costs from other noncurrent assets to long-term debt at December 31, 2015 (see Note 2).

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Cash and Cash Equivalents. Cash and cash equivalents include temporary cash investments with original maturities of three months or less. Accounts Receivable. Accounts receivable relate to gathering and other services provided to our customers and other counterparties. We evaluate the collectability of accounts receivable and the need for an allowance for doubtful accounts based on customer-specific facts and circumstances. To the extent we doubt the collectability of a specific customer or counterparty receivable, we recognize an allowance for doubtful accounts. Other Current Assets. Other current assets primarily consist of the current portion of prepaid expenses that are charged to expense over the period of benefit or the life of the related contract. Property, Plant and Equipment. We record property, plant and equipment at historical cost of construction or fair value of the assets at acquisition. We capitalize expenditures that extend the useful life of an asset or enhance its productivity or efficiency from its original design over the expected remaining period of use. For maintenance and repairs that do not add capacity or extend the useful life of an asset, we recognize expenditures as an expense as incurred. We capitalize project costs incurred during construction, including interest on funds borrowed to finance the construction of facilities, as construction in progress. To the extent that Summit Investments incurred interest expense related to capital projects of assets that have been acquired by the Partnership, the associated interest expense is allocated to the drop down assets as a noncash equity contribution and capitalized into the basis of the asset. We record depreciation on a straight-line basis over an asset’s estimated useful life. We base our estimates for useful life on various factors including age (in the case of acquired assets), manufacturing specifications, technological advances and historical data concerning useful lives of similar assets. Estimates of useful lives follow. Useful lives (In years) Gathering and processing systems and related equipment 30 Other 4-15 Construction in progress is depreciated consistent with its applicable asset class once it is placed in service. Land and line fill are not depreciated. We base an asset’s carrying value on estimates, assumptions and judgments for useful life and salvage value. Upon sale, retirement or other disposal, we remove the carrying value of an asset and its accumulated depreciation from our balance sheet and recognize the related gain or loss, if any. Accrued capital expenditures are reflected in trade accounts payable. Asset Retirement Obligations. We record a liability for asset retirement obligations only if and when a future asset retirement obligation with a determinable life is identified. For identified asset retirement obligations, we then evaluate whether the expected date and related costs of retirement can be estimated. We have concluded that our gathering and processing assets have an indeterminate life because they are owned and will operate for an indeterminate period when properly maintained. Because we did not have sufficient information to reasonably estimate the amount or timing of such obligations and we have no current plan to discontinue use of any significant assets, we did not provide for any asset retirement obligations as of December 31, 2016 or 2015 . Amortizing Intangibles. Upon the acquisition of DFW Midstream, certain of its gas gathering contracts were deemed to have above-market pricing structures while another was deemed to have pricing that was below market. We have recognized the above-market contracts as favorable gas gathering contracts. We have recognized the below-market contract as the unfavorable gas gathering contract and included it in other noncurrent liabilities. We amortize these contracts using a straight-line method over the contract's estimated useful life. We define useful life as the period over which the contract is expected to contribute to our future cash flows. These contracts have original terms ranging from 10 years to 20 years. We recognize the amortization expense associated with these contracts in other revenues. We amortize all other gas gathering contracts, or contract intangibles, over the period of economic benefit based upon expected revenues over the life of the contract. The useful life of these contracts ranges from 10 years to 25 years. We recognize the amortization expense associated with these contracts in depreciation and amortization expense. We have rights-of-way associated with city easements and easements granted within existing rights-of-way. We amortize these intangible assets over the shorter of the contractual term of the rights-of-way or the estimated useful life of the gathering system. The contractual terms of the rights-of-way range from 20 years to 30 years. We recognize the amortization expense associated with rights-of-way assets in depreciation and amortization expense. Goodwill. Goodwill represents consideration paid in excess of the fair value of the net identifiable assets acquired in a business combination. We evaluate goodwill for impairment annually on September 30. We also evaluate goodwill whenever events or circumstances indicate that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. We test goodwill for impairment using a two-step quantitative test. In the first step, we compare the fair value of the reporting unit to its carrying value, including goodwill. To estimate the fair value of the reporting units under step one, we utilize two valuation methodologies: the market approach and the income approach. Both of these approaches incorporate significant estimates and assumptions to calculate enterprise fair value for a reporting unit. The most significant estimates and assumptions inherent within these two valuation methodologies are: (i) determination of the weighted-average cost of capital; (ii) the selection of guideline public companies; (iii) market multiples; (iv) weighting of the income and market approaches; (v) growth rates; (vi) commodity prices; and (vi) the expected levels of throughput volume gathered. Changes in these and other assumptions could materially affect the estimated amount of fair value for any of our reporting units. If the reporting unit’s fair value exceeds its carrying amount, we conclude that the goodwill of the reporting unit has not been impaired and no further work is performed. If we determine that the reporting unit’s carrying value exceeds its fair value, we proceed to step two. In step two, we compare the carrying value of the reporting unit to its implied fair value. Significant estimates and assumptions utilized in the determination of a reporting unit's implied fair value are based on a variety of factors specific to a given reporting unit's individual assets and liabilities as well as market and industry considerations. If we determine that the carrying amount of a reporting unit's goodwill exceeds its implied fair value, we recognize the excess of the carrying value over the implied fair value as an impairment loss. Equity Method Investments. We account for investments in which we exercise significant influence using the equity method so long as we (i) do not control the investee and (ii) are not the primary beneficiary. We recognize these investments in investment in equity method investees in the accompanying consolidated balance sheets. We recognize our proportionate share of earnings or loss in net income on a one-month lag. We recognize an other-than-temporary impairment for losses in the value of equity method investees when evidence indicates that the carrying amount is no longer supportable. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the equity method investee to sustain an earnings capacity that would justify the carrying amount of the investment. A current fair value of an investment that is less than its carrying amount may indicate a loss in value of the investment. We evaluate our equity method investments whenever evidence exists that would indicate a need to assess the investment for potential impairment. Other Noncurrent Assets. Other noncurrent assets primarily consist of external costs incurred in connection with the closing of our Revolving Credit Facility and related amendments. We capitalize and then amortize these debt issuance costs on a straight-line basis over the life of the respective debt instrument. We recognize amortization of Revolving Credit Facility debt issuance costs in interest expense. Debt Issuance Costs. Debt issuance costs, other than those associated with our Revolving Credit Facility, are reflected in the carrying value of the Senior Notes as an adjustment to the principal amount and amortized on a straight-line basis over the life of the respective debt instrument. We recognize Senior Notes debt issuance costs in interest expense. Deferred Purchase Price Obligation. We recognize a liability for the Deferred Purchase Price Obligation (as defined later) to reflect the expected value of the Remaining Consideration to be paid in 2020 for the acquisition of the 2016 Drop Down Assets. We estimate Remaining Consideration by summing the calculations of (i) actual capital expenditures incurred and Business Adjusted EBITDA (as defined later) recognized from the 2016 Drop Down Assets during the period since closing the 2016 Drop Down to the current balance sheet date and (ii) estimates of projected capital expenditures and Business Adjusted EBITDA related to the 2016 Drop Down Assets for periods subsequent to the respective balance sheet date until December 31, 2019. We discount the Remaining Consideration using a commensurate risk-adjusted discount rate and recognize the change in present value of the Remaining Consideration in earnings in the period of change. Our recognition of the change in present value of the Remaining Consideration in the consolidated statements of operations represents the change in present value, which comprises a time value of money concept, as well as (i) actual results from the 2016 Drop Down Assets and (ii) adjustments to projections and the expected value of the Remaining Consideration (see Note 16). Impairment of Long-Lived Assets. We test assets for impairment when events or circumstances indicate that the carrying value of a long-lived asset may not be recoverable. The carrying value of a long-lived asset (except goodwill) is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from its use and eventual disposition. If we conclude that an asset's carrying value will not be recovered through future cash flows, we recognize an impairment loss on the long-lived asset equal to the amount by which the carrying value exceeds its fair value. We determine fair value using either a market-based approach or an income-based approach. We discuss our policy for goodwill impairment above. Derivative Contracts. We have commodity price exposure related to our sale of the physical natural gas we retain from certain DFW Midstream system customers and our procurement of electricity to operate the DFW Midstream system's electric-drive compression assets. Our gas gathering agreements with certain DFW Midstream customers permit us to retain a certain quantity of natural gas that we gather to offset the power costs we incur to operate these electric-drive compression assets. We manage this direct exposure to natural gas and power prices through the use of forward power purchase contracts with wholesale power providers that require us to purchase a fixed quantity of power at a fixed heat rate based on prevailing natural gas prices based on the Waha Hub Index. Because we sell our retainage gas from these customers at prices that are based on the Waha Hub Index, we have effectively fixed the relationship between a portion of our compression electricity expense and natural gas retainage sales. Accounting standards related to derivative instruments and hedging activities allow for normal purchase or sale elections and hedge accounting designations, which generally eliminate or defer the requirement for mark-to-market recognition in net income and thus reduce the volatility of net income that can result from fluctuations in fair values. We have designated these contracts as normal under the normal purchase and sale exception under the accounting standards for derivatives. We do not enter into risk management contracts for speculative purposes. Fair Value of Financial Instruments. The fair-value-measurement standard under GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The standard characterizes inputs used in determining fair value according to a hierarchy that prioritizes those inputs based upon the degree to which the inputs are observable. The three levels of the fair value hierarchy are as follows: • Level 1. Inputs represent quoted prices in active markets for identical assets or liabilities; • Level 2. Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly (for example, quoted market prices for similar assets or liabilities in active markets or quoted market prices for identical assets or liabilities in markets not considered to be active, inputs other than quoted prices that are observable for the asset or liability, or market-corroborated inputs); and • Level 3. Inputs that are not observable from objective sources, such as management’s internally developed assumptions used in pricing an asset or liability (for example, an internally developed present value of future cash flows model that underlies management's fair value measurement). Commitments and Contingencies. We record accruals for loss contingencies when we determine that it is probable that a liability has been incurred and that such economic loss can be reasonably estimated. Such determinations are subject to interpretations of current facts and circumstances, forecasts of future events and estimates of the financial impacts of such events. We recognize gain contingencies when their realization is assured beyond a reasonable doubt. Noncontrolling Interest. Noncontrolling interest represents the ownership interests of third-party entities in the net assets of our consolidated subsidiaries. For financial reporting purposes, we consolidate OpCo and its wholly owned subsidiaries with our wholly owned subsidiaries and the 1% ownership interest in OpCo is reflected as noncontrolling interest in partners' capital. We reflect changes in our ownership of OpCo as adjustments to noncontrolling interest. Revenue Recognition. We generate the majority of our revenue from the gathering, treating and processing services that we provide to our customers. We also generate revenue from our marketing of natural gas, NGLs and condensate. We realize revenues by receiving fees from our customers or by selling the residue natural gas, NGLs and condensate. We recognize revenue earned from fee-based gathering, treating and processing services in gathering services and related fees revenue. We also earn revenue from the sale of physical natural gas purchased from our customers under percentage-of-proceeds arrangements. These revenues are recognized in natural gas, NGLs and condensate sales with corresponding expense recognition for the producer's share of the proceeds in cost of natural gas and NGLs. We sell substantially all of the natural gas that we retain from certain DFW Midstream customers to offset the power expenses of the electric-driven compression on the DFW Midstream system. We also sell condensate retained from our gathering services at Grand River. Revenues from the retainage of natural gas and condensate are recognized in natural gas, NGLs and condensate sales; the associated expense is included in operation and maintenance expense. Certain customers reimburse us for costs we incur on their behalf. We record costs incurred and reimbursed by our customers on a gross basis, with the revenue component recognized in other revenues. We recognize revenue when all of the following criteria are met: (i) persuasive evidence of an exchange arrangement exists, (ii) delivery has occurred or services have been rendered, (iii) the price is fixed or determinable and (iv) collectability is reasonably assured. We provide gathering and/or processing services principally under contracts that contain one or more of the following arrangements: • Fee-based arrangements. Under fee-based arrangements, we receive a fee or fees for one or more of the following services (i) natural gas gathering, treating and/or processing and (ii) crude oil and/or produced water gathering. • Percent-of-proceeds arrangements. Under percent-of-proceeds arrangements, we generally purchase natural gas from producers at the wellhead, or other receipt points, gather the wellhead natural gas through our gathering system, treat the natural gas, process the natural gas and/or sell the natural gas to a third party for processing. We then remit to our producers an agreed-upon percentage of the actual proceeds received from sales of the residue natural gas and NGLs. Certain of these arrangements may also result in returning all or a portion of the residue natural gas and/or the NGLs to the producer, in lieu of returning sales proceeds. The margins earned are directly related to the volume of natural gas that flows through the system and the price at which we are able to sell the residue natural gas and NGLs. Certain of our gathering and processing agreements provide for a monthly, quarterly or annual MVC. Under these MVCs, our customers agree to ship and/or process a minimum volume of production on our gathering systems or to pay a minimum monetary amount over certain periods during the term of the MVC. A customer must make a shortfall payment to us at the end of the contracted measurement period if its actual throughput volumes are less than its MVC for that period. Certain customers are entitled to utilize shortfall payments to offset gathering fees in one or more subsequent contracted measurement periods to the extent that such customer's throughput volumes in a subsequent contracted measurement period exceed its MVC for that contracted measurement period. We recognize customer billings for obligations under their MVCs as revenue when the obligations are billable under the contract and the customer does not have the right to utilize shortfall payments to offset gathering or processing fees in excess of its MVCs in subsequent periods. We record customer billings for obligations under their MVCs as deferred revenue when the customer has the right to utilize shortfall payments to offset gathering or processing fees in subsequent periods. We recognize deferred revenue under these arrangements in revenue once all contingencies or potential performance obligations associated with the related volumes have either (i) been satisfied through the gathering or processing of future excess volume throughput, or (ii) expired (or lapsed) through the passage of time pursuant to the terms of the applicable gathering or processing agreement. We also recognize deferred revenue in revenues when it is determined that a given amount of MVC shortfall payments cannot be recovered by offsetting gathering or processing fees in subsequent contracted measurement periods. In making this determination, we consider both quantitative and qualitative facts and circumstances, including, but not limited to, contract terms, capacity of the associated pipeline or receipt point and/or expectations regarding future investment, drilling and production. We classify deferred revenue as a current liability for arrangements where the expiration of a customer's right to utilize shortfall payments is 12 months or less. We classify deferred revenue as noncurrent for arrangements where the expiration of the right to utilize shortfall payments and our estimate of its potential utilization is more than 12 months. Unit-Based Compensation. For awards of unit-based compensation, we determine a grant date fair value and recognize the related compensation expense in the statements of operations over the vesting period of the respective awards. Income Taxes. As a partnership, we are generally not subject to federal and state income taxes, except as noted below. However, our unitholders are individually responsible for paying federal and state income taxes on their share of our taxable income. Net income or loss for GAAP purposes may differ significantly from taxable income reportable to our unitholders as a result of differences between the tax basis and the GAAP basis of assets and liabilities and the taxable income allocation requirements under our Partnership Agreement. In general, legal entities that are chartered, organized or conducting business in the state of Texas are subject to a franchise tax (the "Texas Margin Tax"). The Texas Margin Tax has the characteristics of an income tax because it is determined by applying a tax rate to a tax base that considers both revenues and expenses. Our financial statements reflect provisions for these tax obligations. Earnings or Loss Per Unit. We determine basic EPU by dividing the net income or loss that is attributed, in accordance with the net income and loss allocation provisions of our Partnership Agreement, to limited partners under the two-class method, after deducting (i) the 1% noncontrolling interest in OpCo (for periods subsequent to the 2016 Drop Down), (ii) any net income or loss of contributed subsidiaries that is attributable to Summit Investments, (iii) the General Partner's approximate 2% interest in net income or loss and (iv) any payment of IDRs, by the weighted-average number of limited partner units outstanding. Diluted EPU reflects the potential dilution that could occur if securities or other agreements to issue common units, such as unit-based compensation, were exercised, settled or converted into common units and included in the weighted-average number of units outstanding. When it is determined that potential common units resulting from an award subject to performance or market conditions should be included in the diluted EPU calculation, the impact is reflected by applying the treasury stock method. Comprehensive Income or Loss. Comprehensive income or loss is the same as net income or loss for all periods presented. Environmental Matters. We are subject to various federal, state and local laws and regulations relating to the protection of the environment. Liabilities for loss contingencies, including environmental remediation costs, arising from claims, assessments, litigation, fines and penalties and other sources are charged to expense when it is probable that a liability has been incurred and the amount of the assessment and/or remediation can be reasonably estimated. We accrue for losses associated with environmental remediation obligations when such losses are probable and reasonably estimable. Such accruals are adjusted as further information develops or circumstances change. Recoveries of environmental remediation costs from other parties or insurers are recorded as assets when their realization is assured beyond a reasonable doubt. Carve-Out Entities, Assets, Liabilities and Expenses. For drop down transactions involving entities that were carved out of other entities, the majority of the assets and liabilities allocated to the carve-out entity are specifically identified based on the original entity's existing divisional organization. Goodwill is allocated to the carve-out entity based on initial purchase accounting estimates. Revenues and depreciation and amortization are specifically identified based on the relationship of the carve-out entity to the original entity's existing divisional structure. Operation and maintenance and general and administrative expenses are allocated to the carve-out entity based on volume throughput. For drop down transactions involving assets, liabilities and expenses that were carved out of other entities, the majority of the assets and liabilities allocated to the carve-out are specifically identified based on the original entity's existing divisional organization. Depreciation and amortization are specifically identified based on the relationship of the carve-out entity to the original entity's existing divisional structure. General and administrative expenses are allocated to the carve-out entity based on an allocation of Summit Investments' consolidated expenses. Allocation of Certain Liabilities in Drop Downs. For drop down transactions involving assets for which their development was funded with debt incurred by Summit Investments or a subsidiary thereof, which was allocated to but not ultimately assumed by the Partnership and later replaced with bank borrowings or debt capital at the Partnership, we allocate a portion of that debt, net of debt issuance costs, to the drop down assets during the common control period. Interest expense is allocated and recognized during the common control period. Any outstanding debt balance or principal is included in the calculation of the excess or deficit of acquired carrying value relative to consideration paid and recognized. Recent Accounting Pronouncements. Accounting standard setters frequently issue new or revised accounting rules. We review new pronouncements to determine the impact, if any, on our financial statements. Accounting standards that have or could possibly have a material effect on our financial statements are discussed below. Recently Adopted Accounting Pronouncements . We have recently adopted the following accounting pronouncements: • ASU No. 2015-03 Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs ("ASU 2015-03"). Under ASU 2015-03, entities that have historically presented debt issuance costs as an asset, related to a recognized debt liability, will be required to present those costs as a direct deduction from the carrying amount of that debt liability. In August 2015, the FASB amended ASU 2015-03 to address the presentation and subsequent measurement of debt issuance costs related to line of credit (“LOC”) arrangements. The amendment permits an entity to defer and present debt issuance costs as an asset and subsequently amortize debt issuance costs ratably over the term of a LOC arrangement, regardless of whether there are outstanding borrowings under that LOC arrangement. This new standard became effective for fiscal years and interim periods within those years, beginning after December 15, 2015. The January 2016 adoption of this update resulted in a reclassification from other noncurrent assets to long-term debt of the debt issuance costs associated with our Senior Notes (see Note 9). Debt issuance costs associated with the Revolving Credit Facility will remain in other noncurrent assets. This standard had no impact on interest expense, net income or loss, EPU or partners' capital. • ASU No. 2016-15 Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force) ("ASU 2016-15"). ASU 2016-15 addresses how certain cash receipts and cash payments are presented and classified in the statements of cash flows. The applicable provisions relate to distributions received from equity method investees. ASU 2016-15 prescribes a method for differentiating between returns of investment (which should be classified as inflows from investing activities) and returns on investment (which should be classified as inflows from operating activities). With respect to distributions from equity method investees, entities make this determination by applying a cumulative-earnings approach or a nature of the distribution approach. The ASU formalizes each of these methods and allows an entity to choose either one as an accounting policy election. ASU 2016-15 is effective for public business entities for fiscal years beginning after December 15, 2017. Early adoption is permitted. The amendments in ASU 2016-15 are to be applied using a retrospective transition method to each period presented. We have adopted the provisions of ASU 2016-15 as of December 31, 2016 and have elected the nature of the distribution approach. The adoption of this standard had no impact on our financial statements. Accounting Pronouncements Pending Adoption . We are currently in the process of evaluating the applicability and/or impact of the following accounting pronouncements: • ASU No. 2014-09 Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09"). Under ASU 2014-09, revenue will be recognized under a five-step model: (i) identify the contract with the customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to performance obligations; and (v) recognize revenue when (or as) the performance obligation is satisfied. ASU 2014-09 is effective for fiscal years and interim periods within those years, beginning after December 15, 2017 and allows for early adoption. We expect to adopt the provisions of ASU 2014-09 effective January 1, 2018 using the modified retrospective method. We have substantially completed our review of our existing contracts under the new guidance. However, we are still assessing the financial statement impact of adoption for certain items discussed below. For contracts where we perform gathering services and earn a per-unit fee which is recognized at a point in time, revenue will be recognized over time as the service is performed, which is expected to accelerate the recognition of revenue by an immaterial amount. In addition, our contracts generally contain forms of what will be considered variable consideration, which will likely be constrained as the volumes are susceptible to factors outside of our control and influence. However, we will be billing amounts that correspond directly to the value transferred such that the resulting revenue recognized will be similar to current GAAP. Due to certain open technical issues, such as contributions in aid of construction and noncash consideration, as well as completion of our evaluations of MVCs, we cannot currently fully conclude on the impact of adoption. We anticipate that we will be able to complete our assessment of the impact of adoption by the end of the third quarter of 2017. • ASU No. 2016-02 Leases (Topic 842) ("ASU 2016-02"). ASU 2016-02 requires that lessees recognize all leases on the balance sheet, with the exception of short-term leases. A lease liability will be recorded for the obligation of a lessee to make lease payments arising from a lease. A right-of-use asset will be recorded which represents the lessee’s right to use, or to control the use of, a specified asset for a lease term. We are currently evaluating the impact of this guidance on lessor accounting but have made no determinations at this time. ASU 2016-02 is effective for public companies for fiscal years beginning after December 15, 2018, and requires the modified retrospective approach for transition. We are currently evaluating the provisions of ASU 2016-02 to determine its impact on our financial statements and related disclosures and expect to adopt its provisions effective January 1, 2019. • ASU No. 2016-08 Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) ("ASU 2016-08"). ASU 2016-08 does not change the core principle of Topic 606, rather it clarifies the implementation guidance on principal versus agent considerations. We expect to adopt the provisions of ASU 2016-08 effective January 1, 2018. Our position regarding the impact of and transition method for this update is the same as for ASU 2014-09. • ASU No. 2016-09 Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting ("ASU 2016-09"). ASU 2016-09 simplifies several aspects for share-based payment award transactions, including income tax consequences, the liability or equity classification of awards and classification on the statements of cash flows. ASU 2016-09 is effective for public

SEGMENT INFORMATION

SEGMENT INFORMATION	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
SEGMENT INFORMATION	SEGMENT INFORMATION As of December 31, 2016, our reportable segments are: • the Utica Shale, which includes our ownership interest in Ohio Gathering and is served by Summit Utica; • the Williston Basin, which is served by Bison Midstream, Polar and Divide and Tioga Midstream; • the Piceance/DJ Basins, which is served by Grand River and Niobrara G&P; • the Barnett Shale, which is served by DFW Midstream; and • the Marcellus Shale, which is served by Mountaineer Midstream. Each of our reportable segments provides midstream services in a specific geographic area. Our reportable segments reflect the way in which we internally report the financial information used to make decisions and allocate resources in connection with our operations. As noted above, the Utica Shale reportable segment includes our investment in Ohio Gathering (see Note 7). Segment assets for the Utica Shale include the associated investment in equity method investees. Income or loss from equity method investees, as reflected on the statements of operations, solely relates to Ohio Gathering and is recognized and disclosed on a one-month lag (see Note 7). No other line items in the statements of operations or cash flows, as disclosed in the tables below, include results for our investment in Ohio Gathering. Corporate and other represents those results that are (i) not specifically attributable to a reportable segment (ii) not individually reportable or (iii) that have not been allocated to our reportable segments, including certain general and administrative expense items and transaction costs, for the purpose of evaluating their performance. Assets by reportable segment follow. December 31, 2016 2015 2014 (In thousands) Assets: Utica Shale (1) $ 906,807 $ 886,224 $ 735,587 Williston Basin 724,084 740,361 861,461 Piceance/DJ Basins 843,440 866,095 941,382 Barnett Shale 404,314 416,586 428,935 Marcellus Shale 224,709 233,116 243,884 Total reportable segment assets 3,103,354 3,142,382 3,211,249 Corporate and other 12,294 22,290 31,213 Eliminations (469 ) — — Total assets $ 3,115,179 $ 3,164,672 $ 3,242,462 __________ (1) Represents the investment in equity method investees for Ohio Gathering (see Note 7) and total assets for Summit Utica. For information on the sale or impairment of long-lived assets, other than goodwill, see Note 4. For information on goodwill by reportable segment, including goodwill impairments, see Note 6. Revenues by reportable segment follow. Year ended December 31, 2016 2015 2014 (In thousands) Revenues: Utica Shale (1) $ 24,263 $ 4,700 $ 190 Williston Basin 122,174 98,929 109,807 Piceance/DJ Basins 149,903 180,418 161,477 Barnett Shale 79,956 88,042 93,001 Marcellus Shale 26,111 28,468 22,694 Total reportable segments revenue 402,407 400,557 387,169 Corporate and other 412 — — Eliminations (457 ) — — Total revenues $ 402,362 $ 400,557 $ 387,169 __________ (1) Excludes revenues earned by Ohio Gathering due to equity method accounting. Counterparties accounting for more than 10% of total revenues were as follows: Year ended December 31, 2016 2015 2014 Percentage of total revenues (1): Counterparty A - Piceance/DJ Basins 14 % 16 % 18 % Counterparty B - Piceance/DJ Basins * 14 % * __________ * Less than 10% (1) Total revenues include recognition of revenue during the year ended December 31, 2015 that was previously deferred in connection with certain MVCs (see Note 8). Depreciation and amortization by reportable segment follows. Year ended December 31, 2016 2015 2014 (In thousands) Depreciation and amortization: Utica Shale (1) $ 4,331 $ 1,417 $ — Williston Basin 33,676 31,376 24,027 Piceance/DJ Basins 49,140 47,433 42,959 Barnett Shale (2) 16,093 16,392 16,601 Marcellus Shale 8,841 8,682 7,648 Total reportable segment depreciation and amortization 112,081 105,300 91,235 Corporate and other 580 603 587 Total depreciation and amortization $ 112,661 $ 105,903 $ 91,822 __________ (1) Excludes depreciation and amortization recognized by Ohio Gathering due to equity method accounting. (2) Includes the amortization expense associated with our favorable and unfavorable gas gathering contracts as reported in other revenues. Cash paid for capital expenditures by reportable segment follow. Year ended December 31, 2016 2015 2014 (In thousands) Cash paid for capital expenditures: Utica Shale (1) $ 78,708 $ 94,994 $ 24,787 Williston Basin 31,541 147,477 227,283 Piceance/DJ Basins 25,719 21,144 42,417 Barnett Shale 3,910 6,875 14,567 Marcellus Shale 1,173 1,306 33,866 Total reportable segment capital expenditures 141,051 271,796 342,920 Corporate and other 1,668 429 460 Total cash paid for capital expenditures $ 142,719 $ 272,225 $ 343,380 __________ (1) Excludes cash paid for capital expenditures by Ohio Gathering due to equity method accounting. We assess the performance of our reportable segments based on segment adjusted EBITDA. We define segment adjusted EBITDA as total revenues less total costs and expenses; plus (i) other income excluding interest income, (ii) our proportional adjusted EBITDA for equity method investees, (iii) depreciation and amortization, (iv) adjustments related to MVC shortfall payments, (v) unit-based and noncash compensation, (vi) Deferred Purchase Price Obligation expense; (vii) impairments and (viii) other noncash expenses or losses, less other noncash income or gains. We define proportional adjusted EBITDA for our equity method investees as the product of (i) total revenues less total expenses, excluding impairments and other noncash income or expense items and (ii) amortization for deferred contract costs; multiplied by our ownership interest in Ohio Gathering during the respective period. For the purpose of evaluating segment performance, we exclude the effect of corporate and other revenues and expenses, such as certain general and administrative expenses (including compensation-related expenses and professional services fees), transaction costs, interest expense, Deferred Purchase Price Obligation income or expense and income tax expense or benefit from segment adjusted EBITDA. In the first quarter of 2015, we discontinued allocating certain corporate expenses, primarily salaries, benefits, incentive compensation and rent expense, to our then-reportable segments. This change in allocation methodology was not implemented by Summit Investments with respect to Polar and Divide or the 2016 Drop Down Assets. As a result of accounting for their activity on an as-if pooled basis due to common control, general and administrative expense allocations were higher for Polar and Divide and the 2016 Drop Down Assets during their respective common control periods. Segment adjusted EBITDA by reportable segment follows. Year ended December 31, 2016 2015 2014 (In thousands) Reportable segment adjusted EBITDA: Utica Shale (1) $ 66,637 $ 35,873 $ 6,176 Williston Basin 79,475 34,008 30,009 Piceance/DJ Basins 109,241 110,222 110,763 Barnett Shale 54,634 59,526 60,528 Marcellus Shale 19,203 23,214 15,940 Total of reportable segments’ measures of profit or loss $ 329,190 $ 262,843 $ 223,416 __________ (1) Includes our proportional share of adjusted EBITDA for Ohio Gathering, based on a one-month lag. A reconciliation of loss before income taxes and loss from equity method investees to total of reportable segments' measures of profit or loss follows. Year ended December 31, 2016 2015 2014 (In thousands) Reconciliation of loss before income taxes and loss from equity method investees to total of reportable segments' measures of profit or loss: Loss before income taxes and loss from equity method investees $ (7,768 ) $ (216,268 ) $ (29,802 ) Add: Corporate and other 37,589 27,352 15,441 Interest expense 63,810 59,092 48,586 Deferred Purchase Price Obligation expense 55,854 — — Depreciation and amortization 112,661 105,903 91,822 Proportional adjusted EBITDA for equity method investees 45,602 33,667 6,006 Adjustments related to MVC shortfall payments 11,600 (11,902 ) 26,565 Unit-based and noncash compensation 7,985 7,017 5,841 Loss (gain) on asset sales, net 93 (172 ) 442 Long-lived asset impairment 1,764 9,305 5,505 Goodwill impairment — 248,851 54,199 Less: Interest income — 2 4 Impact of purchase price adjustment — — 1,185 Total of reportable segments' measures of profit or loss $ 329,190 $ 262,843 $ 223,416 We include adjustments related to MVC shortfall payments in our calculation of segment adjusted EBITDA to account for (i) the net increases or decreases in deferred revenue for MVC shortfall payments and (ii) our inclusion of expected annual MVC shortfall payments. With respect to the impact of a net change in deferred revenue for MVC shortfall payments, we treat increases in deferred revenue balances as a favorable adjustment to segment adjusted EBITDA, while decreases in deferred revenue balances are treated as an unfavorable adjustment to segment adjusted EBITDA. We also include a proportional amount of any historical and expected MVC shortfall payments in each quarter prior to the quarter in which we actually recognize the shortfall payment. The expected MVC shortfall payment adjustments have not been billed to our customers and are not recognized in our consolidated financial statements. Adjustments related to MVC shortfall payments by reportable segment follow. Year ended December 31, 2016 Williston Basin Piceance/DJ Basins Barnett Shale Total (In thousands) Adjustments related to MVC shortfall payments: Net change in deferred revenue for MVC shortfall payments $ 8,691 $ 3,288 $ (677 ) $ 11,302 Expected MVC shortfall payments — (317 ) 615 298 Total adjustments related to MVC shortfall payments $ 8,691 $ 2,971 $ (62 ) $ 11,600 Year ended December 31, 2015 Williston Basin Piceance/DJ Basins Barnett Shale Total (In thousands) Adjustments related to MVC shortfall payments: Net change in deferred revenue for MVC shortfall payments $ 11,870 $ (21,623 ) $ (1,700 ) $ (11,453 ) Expected MVC shortfall payments — 33 (482 ) (449 ) Total adjustments related to MVC shortfall payments $ 11,870 $ (21,590 ) $ (2,182 ) $ (11,902 ) Year ended December 31, 2014 Williston Basin Piceance/DJ Basins Barnett Shale Total (In thousands) Adjustments related to MVC shortfall payments: Net change in deferred revenue for MVC shortfall payments $ 10,743 $ 14,813 $ 821 $ 26,377 Expected MVC shortfall payments — 381 (193 ) 188 Total adjustments related to MVC shortfall payments $ 10,743 $ 15,194 $ 628 $ 26,565

PROPERTY, PLANT, AND EQUIPMENT,

PROPERTY, PLANT, AND EQUIPMENT, NET	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT, AND EQUIPMENT, NET	PROPERTY, PLANT AND EQUIPMENT, NET Details on property, plant and equipment follow. December 31, 2016 2015 (In thousands) Gathering and processing systems and related equipment $ 2,026,363 $ 1,883,139 Construction in progress 39,954 75,132 Land and line fill 11,442 11,055 Other 35,227 32,427 Total 2,112,986 2,001,753 Less accumulated depreciation 259,315 188,970 Property, plant and equipment, net $ 1,853,671 $ 1,812,783 During 2016, 2015 and 2014, we identified certain events, facts and circumstances which indicated that certain of our property, plant and equipment could be impaired. As such, we reviewed the assets that had been identified as potentially impaired and estimated the fair value of the identified property, plant and equipment using a market-based approach. For the assets which had fair values below their carrying value, we recognized the following long-lived asset impairments, by segment. Year ended December 31, 2016 2015 2014 (In thousands) Long-lived asset impairment: Williston Basin $ 569 $ 7,554 $ — Piceance/DJ Basins — 1,220 — Barnett Shale 1,195 531 5,505 Our impairment determinations, in the context of these reviews, involved significant assumptions and judgments. Differing assumptions regarding any of these inputs could have a significant effect on the various valuations. As such, the fair value measurements utilized within these estimates are classified as non-recurring Level 3 measurements in the fair value hierarchy because they are not observable from objective sources. Due to the volatility of the inputs used, we cannot predict the likelihood of any future impairment. During the fourth quarters of 2015 and 2014, we identified a need to evaluate the goodwill associated with certain of our gathering systems (see Note 6). In connection with these evaluations, we also evaluated the related property, plant and equipment associated therewith for impairment and concluded that no impairment was necessary. Depreciation expense and capitalized interest follow. Year ended December 31, 2016 2015 2014 (In thousands) Depreciation expense $ 70,770 $ 63,915 $ 53,064 Capitalized interest 3,709 3,372 4,646

AMORTIZING INTANGIBLE ASSETS AN

AMORTIZING INTANGIBLE ASSETS AND UNFAVORABLE GAS GATHERING CONTRACT	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
AMORTIZING INTANGIBLE ASSETS AND UNFAVORABLE GAS GATHERING CONTRACT	AMORTIZING INTANGIBLE ASSETS AND UNFAVORABLE GAS GATHERING CONTRACT Details regarding our intangible assets and the unfavorable gas gathering contract (included in other noncurrent liabilities), all of which are subject to amortization, follow. December 31, 2016 Useful lives (In years) Gross carrying amount Accumulated amortization Net (Dollars in thousands) Favorable gas gathering contracts 18.7 $ 24,195 $ (10,795 ) $ 13,400 Contract intangibles 12.5 426,464 (146,468 ) 279,996 Rights-of-way 26.1 153,015 (24,959 ) 128,056 Total intangible assets $ 603,674 $ (182,222 ) $ 421,452 Unfavorable gas gathering contract 10.0 $ 10,962 $ (6,916 ) $ 4,046 December 31, 2015 Useful lives (In years) Gross carrying amount Accumulated amortization Net (Dollars in thousands) Favorable gas gathering contracts 18.7 $ 24,195 $ (9,534 ) $ 14,661 Contract intangibles 12.5 426,464 (111,052 ) 315,412 Rights-of-way 26.3 150,143 (18,906 ) 131,237 Total intangible assets $ 600,802 $ (139,492 ) $ 461,310 Unfavorable gas gathering contract 10.0 $ 10,962 $ (6,077 ) $ 4,885 During the fourth quarters of 2015 and 2014, we identified a need to evaluate the goodwill associated with certain of our gathering systems (see Note 6). In connection with these evaluations, we also evaluated the related intangible assets associated therewith for impairment and concluded that no impairment was necessary. We recognized amortization expense in other revenues as follows: Year ended December 31, 2016 2015 2014 (In thousands) Amortization expense – favorable gas gathering contracts $ (1,261 ) $ (1,478 ) $ (1,741 ) Amortization expense – unfavorable gas gathering contract 839 692 797 We recognized amortization expense in costs and expenses as follows: Year ended December 31, 2016 2015 2014 (In thousands) Amortization expense – contract intangibles $ 35,416 $ 35,339 $ 32,554 Amortization expense – rights-of-way 6,053 5,863 5,260 The estimated aggregate annual amortization expected to be recognized as of December 31, 2016 for each of the five succeeding fiscal years follows. Intangible assets Unfavorable gas gathering contract (In thousands) 2017 $ 41,854 $ 2,158 2018 41,323 1,888 2019 41,154 — 2020 43,403 — 2021 41,630 —

GOODWILL

GOODWILL	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL	GOODWILL Current and historical goodwill is related to the original acquisitions of the Grand River, Bison Midstream, Polar and Divide and Mountaineer Midstream systems. The assets acquired in the Polar and Divide Drop Down were carved out of Meadowlark Midstream. As such, we elected to apply the historical cost approach to determine the amount of goodwill to assign to the Polar and Divide reporting unit. Our procedures indicated that the remaining goodwill balance at Meadowlark Midstream immediately prior to the Polar and Divide Drop Down was entirely attributable to the Polar and Divide reporting unit. A rollforward of goodwill by reportable segment and in total follows. Piceance/DJ Basins Williston Basin Marcellus Shale Total (In thousands) Goodwill, January 1, 2015 $ 45,478 $ 203,373 $ 16,211 $ 265,062 Goodwill impairment (45,478 ) (203,373 ) — (248,851 ) Goodwill, December 31, 2015 — — 16,211 16,211 Goodwill impairment — — — — Goodwill, December 31, 2016 $ — $ — $ 16,211 $ 16,211 Accumulated goodwill impairments by reportable segment for those reporting units that have previously recognized goodwill follow. December 31, 2016 2015 2014 (In thousands) Accumulated goodwill impairment: Piceance/DJ Basins $ 45,478 $ 45,478 $ — Williston Basin 257,572 257,572 54,199 Total accumulated goodwill impairment $ 303,050 $ 303,050 $ 54,199 As discussed in Note 2, we evaluate goodwill for impairment annually on September 30 and whenever events or circumstances indicate that it is more likely than not that the fair value of a reporting unit is less than its carrying value, including goodwill. We performed our annual goodwill impairment testing for the Mountaineer Midstream reporting unit as of September 30, 2016 using a combination of the income and market approaches. We determined that its fair value substantially exceeded its carrying value, including goodwill; as such, there were no impairments of goodwill during 2016. 2014 Annual Impairment Evaluation . In September 2014, we performed our annual goodwill impairment testing as of September 30 using a combination of the income and market approaches. We determined that the fair value of the Grand River, Mountaineer Midstream and Polar and Divide reporting units substantially exceeded their carrying value, including goodwill. We also determined that the fair value of the Bison Midstream reporting unit exceeded its carrying value. However, it did not exceed its carrying value, including goodwill, by a substantial amount. Because the fair value of each reporting unit exceeded its carrying value, including goodwill, there were no associated impairments of goodwill in connection with our 2014 annual goodwill impairment test. Fourth Quarter 2014 Goodwill Impairment . During the latter part of the fourth quarter of 2014, the declines in prices for natural gas, NGLs and crude oil accelerated, negatively impacting producers in each of our areas of operation. As a result, we considered whether the goodwill associated with our Grand River, Mountaineer Midstream, Polar and Divide and Bison Midstream reporting units could have been impaired. Our assessments related to Grand River and Mountaineer Midstream did not result in an indication that the associated goodwill had been impaired. Our assessment related to the Polar and Divide and Bison Midstream reporting units did result in an indication that the associated goodwill could have been impaired. We noted that both reporting units were impacted by the recent price declines. We also noted that a key Bison Midstream customer announced that it was delaying its previously announced drilling plans which caused SMLP to reduce its forecasted volume assumption. The impact of these events increased the likelihood that the goodwill associated with the Polar and Divide and Bison Midstream reporting units could have been impaired. As such, we concluded that a triggering event occurred during the fourth quarter of 2014 requiring that we test the goodwill associated with these reporting units for impairment. In connection therewith, we reperformed our step one analyses for each as of December 31, 2014. To estimate the fair value of the reporting units, we utilized two valuation methodologies: the market approach and the income approach. The results of our step one goodwill impairment testing indicated that the fair value of the Polar and Divide reporting unit exceeded its carrying value, including goodwill as of December 31, 2014. As a result, there was no associated impairment of goodwill in connection with the fourth quarter 2014 triggering event. The results of our step one goodwill impairment testing indicated that the fair value of the Bison Midstream reporting unit was below its carrying value, including goodwill as of December 31, 2014. As a result, we performed step two of the goodwill impairment test. To perform step two, we first determined the fair values of the identifiable assets and liabilities. Significant assumptions utilized in the determination of the fair value of each reporting unit's individual assets and liabilities included the determination of discount rate and contributory asset charge utilized in our calculation of the fair value of our contract intangibles, expected levels of throughput volume and associated capital expenditures and commodity prices. In the first quarter of 2015, we finalized our calculations of the fair values of the identified assets and liabilities in step two of the December 31, 2014 goodwill impairment testing for the Bison Midstream reporting unit. This process confirmed the preliminary goodwill impairment of $54.2 million that was recognized as of December 31, 2014. 2015 Annual Impairment Evaluation . We performed our annual goodwill impairment testing as of September 30, 2015 using a combination of the income and market approaches. We determined that the fair value of the Grand River, Mountaineer Midstream and Polar and Divide reporting units exceeded their carrying value, including goodwill. Because the fair value of each reporting unit exceeded its carrying value, including goodwill, there were no associated impairments of goodwill in connection with our 2015 annual goodwill impairment test. Fourth Quarter 2015 Goodwill Impairments . During the latter part of the fourth quarter of 2015 and the early part of the first quarter of 2016, the declines in forward prices for natural gas, NGLs and crude oil accelerated significantly. As a result, the energy sector's public debt and equity market experienced increased volatility, particularly for comparable companies operating in the midstream services sector. Additionally, during this period, the values of our publicly traded equity and debt instruments decreased as did those of comparable midstream companies. Due to (i) the increased market volatility, (ii) the decrease in market values of comparable companies, (iii) the continued trend of falling commodity prices and (iv) the finalization of our annual financial and operating plans which took into account changes resulting from expected levels of drilling activity, we concluded that a triggering event occurred during the fourth quarter of 2015 requiring that we test the goodwill associated with our Grand River and Polar and Divide reporting units. Our assessment related to Mountaineer Midstream did not result in an indication that a triggering event had occurred for Mountaineer Midstream. In connection therewith, we updated our step one analyses as of December 31, 2015. These updated analyses indicated that the carrying values for Grand River and Polar and Divide exceeded their estimated fair values. As a result, we then performed step two of the goodwill impairment test for both reporting units. To perform step two, we first determined the estimated fair values of the identifiable assets and liabilities. Significant assumptions utilized in the determination of the fair value of each reporting unit's individual assets and liabilities included the determination of discount rate taking into consideration company-specific risks and contributory asset charge utilized in our contract intangibles, expected levels of throughput volume and associated capital expenditures. In the first quarter of 2016, we finalized our calculations of the fair values of the identified assets and liabilities in step two of the December 31, 2015 goodwill impairment testing for the Grand River and Polar and Divide reporting units. This process confirmed the preliminary goodwill impairments of $45.5 million for Grand River and $203.4 million for Polar and Divide that were recognized as of December 31, 2015. Fair Value Measurement. Our impairment determinations, in the context of (i) our annual impairment evaluations and (ii) our other-than-annual impairment evaluations involved significant assumptions and judgments, as discussed above. Differing assumptions regarding any of these inputs could have a significant effect on the various valuations. As such, the fair value measurements utilized within these models are classified as non-recurring Level 3 measurements in the fair value hierarchy because they are not observable from objective sources. Due to the volatility of the inputs used, we cannot predict the likelihood of any future impairment.

EQUITY METHOD INVESTMENTS

EQUITY METHOD INVESTMENTS	12 Months Ended
	Dec. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
EQUITY METHOD INVESTMENTS	EQUITY METHOD INVESTMENTS Ohio Gathering owns, operates and is currently developing midstream infrastructure consisting of a liquids-rich natural gas gathering system, a dry natural gas gathering system and a condensate stabilization facility in the Utica Shale Play in southeastern Ohio. Ohio Gathering provides gathering services pursuant to primarily long-term, fee-based gathering agreements, which include acreage dedications. In January 2014, Summit Investments acquired a 1% ownership interest in Ohio Gathering from Blackhawk Midstream, LLC ("Blackhawk") for $190.0 million. Concurrent with this acquisition, Summit Investments made an $8.4 million capital contribution to Ohio Gathering to maintain its 1% ownership interest. The ownership interest Summit Investments acquired from Blackhawk included an option to increase the holder's ownership interest in Ohio Gathering to 40% (the "Option"). In May 2014, Summit Investments exercised the Option to increase its ownership to 40% (the "Option Exercise") and made the following payments (i) $326.6 million of capital contribution true-ups, (ii) $50.4 million of additional capital contributions to maintain its 40% ownership interest and (iii) $5.4 million of management fee payments that were recognized as capital contributions in its Ohio Gathering capital accounts. Concurrent with and subsequent to the Option Exercise, the non-affiliated owners have retained their respective 60% ownership interest in Ohio Gathering (the "Non-affiliated Owners"). Summit Investments accounted for its initial ownership interests in Ohio Gathering under the cost method due to its ownership percentage and because it determined that it was not the primary beneficiary. Subsequent to the Option Exercise, Summit Investments accounted for its ownership interests in Ohio Gathering as equity method investments because it had joint control with the Non-affiliated Owners, which gave it significant influence. This shift from the cost method to the equity method required that Summit Investments retrospectively reflect its investment in Ohio Gathering and the associated results of operations as if it had been utilizing the equity method since the inception of its investment. Summit Investments recognized the $190.0 million that it paid to Blackhawk as an investment in Ohio Gathering at inception. In addition, Ohio Gathering had assigned a value of $7.5 million to the Option, recognized it initially as an asset and concurrently attributed the value of the Option to Blackhawk's capital account. Upon acquiring Blackhawk's interest, the Option was reclassified from Blackhawk's capital account to Summit Investments' capital account in Ohio Gathering's records. Neither of these transactions involved a flow of funds to or from Ohio Gathering. As such, they created a basis difference between its recorded investment in equity method investees and that recognized and attributed to Summit Investments by Ohio Gathering. In accordance with the retrospective recognition triggered by the Option Exercise, in February 2014, Summit Investments began amortizing these basis differences over the weighted-average remaining life of the contracts underlying Ohio Gathering's operations. The impact of amortizing these two basis differences resulted in a net decrease to Summit Investments' investment in equity method investees. Subsequent to the Option Exercise, Summit Investments continued to make capital contributions to Ohio Gathering along with receiving distributions such that it maintained its 40% ownership interest through the 2016 Drop Down. Subsequent to the 2016 Drop Down, SMLP began making contributions and receiving distributions and will also continue amortizing the two basis differences, as noted above. In June 2016, an impairment loss was recognized by OCC. We recorded our 40% share of the impairment loss, or $37.8 million , in loss from equity method investees in the consolidated statements of operations. A reconciliation of our 40% ownership interest in Ohio Gathering to our investment per Ohio Gathering's books and records follows. 2016 2015 (In thousands) Investment in equity method investees, December 31 $ 707,415 $ 751,168 December cash distributions 3,172 3,472 December cash contributions (5,318 ) — Basis difference (143,536 ) (156,888 ) Investment in equity method investees, net of basis difference, November 30 $ 561,733 $ 597,752 Summarized balance sheet information for OGC and OCC follows (amounts represent 100% of investee financial information). November 30, 2016 November 30, 2015 OGC OCC OGC OCC (In thousands) Current assets $ 43,797 $ 2,546 $ 42,053 $ 6,633 Noncurrent assets 1,330,199 31,195 1,333,726 127,663 Total assets $ 1,373,996 $ 33,741 $ 1,375,779 $ 134,296 Current liabilities $ 22,067 $ 3,448 $ 34,996 $ 6,234 Noncurrent liabilities 8,396 13,111 5,538 12,545 Total liabilities $ 30,463 $ 16,559 $ 40,534 $ 18,779 Summarized statements of operations information for OGC and OCC follows (amounts represent 100% of investee financial information). Twelve months ended November 30, 2016 Twelve months ended November 30, 2015 Ten months ended November 30, 2014 OGC OCC OGC OCC OGC OCC (In thousands) Total revenues $ 148,662 $ 15,791 $ 120,623 $ 9,467 $ 45,313 $ — Total operating expenses 96,647 111,528 96,948 15,633 64,166 2,208 Net income (loss) 52,009 (94,230 ) 23,655 (6,852 ) (18,853 ) (2,208 )

DEFERRED REVENUE

DEFERRED REVENUE	12 Months Ended
	Dec. 31, 2016
Deferred Revenue Disclosure [Abstract]
Deferred Revenue	DEFERRED REVENUE The majority of our gas gathering agreements provide for a monthly, quarterly or annual MVC from our customers. The amount of the shortfall payment is based on the difference between the actual throughput volume shipped or processed for the applicable period and the MVC for the applicable period, multiplied by the applicable gathering or processing fee. Many of our gas gathering agreements contain provisions that can reduce or delay the cash flows that we expect to receive from our MVCs to the extent that a customer's actual throughput volumes are above or below its MVC for the applicable contracted measurement period. These provisions include the following: • To the extent that a customer's throughput volumes are less than its MVC for the applicable period and the customer makes a shortfall payment, it may be entitled to an offset in one or more subsequent periods to the extent that its throughput volumes in subsequent periods exceed its MVC for those periods. In such a situation, we would not receive gathering fees on throughput in excess of that customer's MVC (depending on the terms of the specific gas gathering agreement) to the extent that the customer had made a shortfall payment with respect to one or more preceding measurement periods (as applicable). • To the extent that a customer's throughput volumes exceed its MVC in the applicable contracted measurement period, it may be entitled to apply the excess throughput against its aggregate MVC, thereby reducing the period for which its annual MVC applies. As a result of this mechanism, the weighted-average remaining period for which our MVCs apply will be less than the weighted-average of the original stated contract terms of our MVCs. • To the extent that certain of our customers' throughput volumes exceed its MVC for the applicable period, there is a crediting mechanism that allows the customer to build a bank of credits that it can utilize in the future to reduce shortfall payments owed in subsequent periods, subject to expiration if there is no shortfall in subsequent periods. The period over which this credit bank can be applied to future shortfall payments varies, depending on the particular gas gathering agreement. A rollforward of current deferred revenue follows. Williston Basin Piceance/DJ Basins Barnett Shale Total current (In thousands) Current deferred revenue, December 31, 2014 $ — $ — $ 2,377 $ 2,377 Additions — 2,743 677 3,420 Less revenue recognized — 2,743 2,377 5,120 Current deferred revenue, December 31, 2015 — — 677 677 Additions — 11,672 — 11,672 Less revenue recognized — 11,672 677 12,349 Current deferred revenue, December 31, 2016 $ — $ — $ — $ — A rollforward of noncurrent deferred revenue follows. Williston Basin Piceance/DJ Basins Barnett Shale Total noncurrent (In thousands) Noncurrent deferred revenue, December 31, 2014 $ 17,132 $ 38,107 $ — $ 55,239 Additions 11,897 12,765 — 24,662 Less revenue recognized 27 34,388 — 34,415 Noncurrent deferred revenue, December 31, 2015 29,002 16,484 — 45,486 Additions 8,691 3,700 — 12,391 Less revenue recognized — 412 — 412 Noncurrent deferred revenue, December 31, 2016 $ 37,693 $ 19,772 $ — $ 57,465 In September 2015, we determined that it would be remote for a certain Piceance/DJ Basins customer to ship volumes in excess of its MVC such that it could recover certain previous MVC shortfall payments, which had been recorded as deferred revenue, as an offset to future gathering fees. We based this determination on public statements by the customer regarding future drilling and investment plans in the area covered by the MVC contract. Due to the remote nature of having to perform any services associated with the previously deferred gathering revenue, we evaluated (i) the terms of the customer contract, (ii) the capacity of the central receipt points for throughput volumes covered by the MVC contract and (iii) the size of the AMI, including the number of drilling locations to determine what amount of previously deferred gathering revenue had met the criteria for revenue recognition. Our evaluation resulted in the recognition of $34.4 million of gathering services and related fees revenue that had been previously deferred with a corresponding reduction to deferred revenue. This represents recognition of amounts deferred up to the September 2015 event triggering the conclusion that the associated shortfall payments should be recognized as revenue. As of December 31, 2016 , accounts receivable included $46.0 million of total shortfall payment billings, of which $8.5 million related to MVC arrangements that can be utilized to offset gathering fees in subsequent periods.

DEBT

DEBT	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
DEBT	DEBT Debt consisted of the following: December 31, 2016 2015 (In thousands) Summit Holdings variable rate senior secured Revolving Credit Facility (3.27% at December 31, 2016 and 2.93% at December 31, 2015) due November 2018 $ 648,000 $ 344,000 Summit Holdings 5.5% senior unsecured notes due August 2022 300,000 300,000 Less unamortized debt issuance costs (1) (3,516 ) (4,139 ) Summit Holdings 7.5% senior unsecured notes due July 2021 300,000 300,000 Less unamortized debt issuance costs (1) (4,183 ) (5,091 ) SMP Holdings variable rate senior secured revolving credit facility (2.43% at December 31, 2015) (2) — 115,000 SMP Holdings variable rate senior secured term loan (2.43% at December 31, 2015) (2) — 217,500 Total long-term debt $ 1,240,301 $ 1,267,270 __________ (1) Issuance costs are being amortized over the life of the notes. (2) Debt was allocated to the 2016 Drop Down Assets prior to the closing of the 2016 Drop Down but was retained by Summit Investments after close. The aggregate amount of debt maturing during each of the years after December 31, 2016 are as follow (in thousands): 2017 $ — 2018 648,000 2019 — 2020 — 2021 300,000 Thereafter 300,000 Total long-term debt $ 1,248,000 Revolving Credit Facility. Summit Holdings has a senior secured 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 November 2018, and includes a $200.0 million accordion feature. In February 2016, we closed on an amendment to the Revolving Credit Facility, which became effective concurrent with the March 2016 closing of the 2016 Drop Down. In connection with this amendment, (i) the Revolving Credit Facility's borrowing capacity increased from $700.0 million to $1.25 billion , (ii) a new investment basket allowing the Co-Issuers (as defined below) to buy back up to $100.0 million of our outstanding senior unsecured notes was included, (iii) the total leverage ratio was increased to 5.5 to 1.0 through December 31, 2016 and (iv) various amendments were approved to facilitate the 2016 Drop Down. There was no change to the pricing or the maturity date of the Revolving Credit Facility in connection with this amendment. Borrowings under the Revolving Credit Facility bear interest at LIBOR or an Alternate Base Rate ("ABR") plus an applicable margin ranging from 0.75% to 1.75% for ABR borrowings and 1.75% to 2.75% for LIBOR borrowings, with the commitment fee ranging from 0.30% to 0.50% in each case based on our relative leverage at the time of determination. At December 31, 2016 , the applicable margin under LIBOR borrowings was 2.50% , the interest rate was 3.27% and the unused portion of the Revolving Credit Facility totaled $602.0 million (subject to a commitment fee of 0.50% ). The Revolving Credit Facility is secured by the membership interests of Summit Holdings and those of its subsidiaries. Substantially all of Summit Holdings' and its subsidiaries' assets are pledged as collateral under the Revolving Credit Facility. Prior to the 2016 Drop Down, the Revolving Credit Facility and Summit Holdings' obligations, were guaranteed by SMLP, Bison Midstream and its subsidiaries, Grand River and its subsidiary and DFW Midstream (the "Guarantor Subsidiaries" prior to the 2016 Drop Down). Following the 2016 Drop Down, OpCo GP, OpCo, Summit Utica, Meadowlark Midstream and Tioga Midstream were added as subsidiary guarantors of the Revolving Credit Facility and the Senior Notes (as defined below). On August 5, 2016, a consent and waiver agreement to the Revolving Credit Facility was executed effective March 30, 2016 (the "Consent and Waiver Agreement"), which removed the guarantees of OpCo, Summit Utica, Meadowlark Midstream and Tioga Midstream (collectively, the "Non-Guarantor Subsidiaries") from the Revolving Credit Facility and concurrently, from the Senior Notes. The Revolving Credit Facility contains affirmative and negative covenants customary for credit facilities of its size and nature that, among other things, limit or restrict the ability to: (i) incur additional debt; (ii) make investments; (iii) engage in certain mergers, consolidations, acquisitions or sales of assets; (iv) enter into swap agreements and power purchase agreements; (v) enter into leases that would cumulatively obligate payments in excess of $30.0 million over any 12 -month period; and (vi) prohibits the payment of distributions by Summit Holdings if a default then exists or would result therefrom, and otherwise limits the amount of distributions Summit Holdings can make. In addition, the Revolving Credit Facility requires Summit Holdings to maintain a ratio of consolidated trailing 12 -month earnings before interest, income taxes, depreciation and amortization ("EBITDA," as defined in the credit agreement) to net interest expense of not less than 2.5 to 1.0 (as defined in the credit agreement) and a ratio of total net indebtedness to consolidated trailing 12 -month EBITDA of not more than 5.0 to 1.0, or not more than 5.5 to 1.0 for up to 270 days following certain acquisitions. Additionally, the total leverage ratio upper limit can be increased from 5.0 to 1.0 to 5.5 to 1.0 at our option, subject to the inclusion of a senior secured leverage ratio (senior secured net indebtedness to consolidated trailing 12 -month EBITDA, as defined in the credit agreement) upper limit of 3.75 to 1.0. As of December 31, 2016 , we were in compliance with the Revolving Credit Facility's covenants. There were no defaults or events of default during the year ended December 31, 2016 . Senior Notes. In July 2014, Summit Holdings and its 100% owned finance subsidiary, Finance Corp., together with Summit Holdings, the "Co-Issuers"), co-issued $300.0 million of 5.5% senior unsecured notes maturing August 15, 2022 (the " 5.5% Senior Notes"). In June 2013, the Co-Issuers co-issued $300.0 million of 7.5% senior unsecured notes maturing July 1, 2021 (the " 7.5% Senior Notes" and together with the 5.5% Senior Notes, the "Senior Notes"). Following execution of the Consent and Waiver Agreement, Bison Midstream and its subsidiaries, Grand River and its subsidiary, DFW Midstream and OpCo GP (collectively, the "Guarantor Subsidiaries" subsequent to the 2016 Drop Down after giving effect to the Consent and Waiver Agreement) and SMLP have fully and unconditionally and jointly and severally guaranteed the 5.5% Senior Notes and the 7.5% Senior Notes (collectively, the "Senior Notes") (see Note 17). Prior to execution of the Consent and Waiver Agreement, the Senior Notes were guaranteed by SMLP and its then-subsidiaries other than the Co-Issuers. At no time have the Senior Notes been guaranteed by the Co-Issuers. There are no significant restrictions on the ability of SMLP or Summit Holdings to obtain funds from its subsidiaries by dividend or loan. Finance Corp. has had no assets or operations since inception in 2013. Subsequent Events . In February 2017, we amended the 2014 SRS to include additional guarantor subsidiaries and completed a public offering of $500.0 million principal 5.75% senior unsecured notes maturing April 15, 2025. Concurrent therewith, we made a tender offer to purchase all of the outstanding 7.5% Senior Notes. The tender offer expired on February 14, 2017 with $276.9 million validly tendered. On February 16, 2017, we issued a notice of redemption for the 7.5% Senior Notes that remained outstanding subsequent to the tender offer. The remaining $23.1 million of 7.5% Senior Notes will be redeemed on March 18, 2017, with payment made on March 20, 2017. In addition to using the proceeds to purchase all of the outstanding 7.5% Senior Notes, we have also used the proceeds to repay a portion of the outstanding borrowings under our Revolving Credit Facility. Remaining unamortized debt issuance costs on the 7.5% Senior Notes will be written off in the first quarter of 2017. 5.5% Senior Notes . We pay interest on the 5.5% Senior Notes semi-annually in cash in arrears on February 15 and August 15 of each year. The 5.5% Senior Notes are senior, unsecured obligations and rank equally in right of payment with all of our existing and future senior obligations. The 5.5% Senior Notes are effectively subordinated in right of payment to all of our secured indebtedness, to the extent of the collateral securing such indebtedness. We used the proceeds from the issuance of the 5.5% Senior Notes to repay a portion of the balance outstanding under our Revolving Credit Facility. At any time prior to August 15, 2017, the Co-Issuers may redeem up to 35% of the aggregate principal amount of the 5.5% Senior Notes at a redemption price of 105.500% of the principal amount of the 5.5% Senior Notes, plus accrued and unpaid interest, if any, to the redemption date, with an amount not greater than the net cash proceeds of certain equity offerings. On and after August 15, 2017, the Co-Issuers may redeem all or part of the 5.5% Senior Notes at a redemption price of 104.125% (with the redemption premium declining ratably each year to 100.000% on and after August 15, 2020), plus accrued and unpaid interest, if any. Debt issuance costs of $5.1 million are being amortized over the life of the senior notes. The 5.5% Senior Notes' indenture restricts SMLP’s and the Co-Issuers’ ability and the ability of certain of their subsidiaries to: (i) incur additional debt or issue preferred stock; (ii) make distributions, repurchase equity or redeem subordinated debt; (iii) make payments on subordinated indebtedness; (iv) create liens or other encumbrances; (v) make investments, loans or other guarantees; (vi) sell or otherwise dispose of a portion of their assets; (vii) engage in transactions with affiliates; and (viii) make acquisitions or merge or consolidate with another entity. These covenants are subject to a number of important exceptions and qualifications. At any time when the senior notes are rated investment grade by each of Moody’s Investors Service, Inc. and Standard & Poor’s Ratings Services and no default or event of default under the indenture has occurred and is continuing, many of these covenants will terminate. The 5.5% Senior Notes' indenture provides that each of the following is an event of default: (i) default for 30 days in the payment when due of interest on the 5.5% Senior Notes; (ii) default in the payment when due of the principal of, or premium, if any, on the 5.5% Senior Notes; (iii) failure by the Co-Issuers or SMLP to comply with certain covenants relating to mergers and consolidations, change of control or asset sales; (iv) failure by SMLP for 180 days after notice to comply with certain covenants relating to the filing of reports with the SEC; (v) failure by the Co-Issuers or SMLP for 30 days after notice to comply with any of the other agreements in the indenture; (vi) specified defaults under any mortgage, indenture or instrument under which there may be issued or by which there may be secured or evidenced any indebtedness for money borrowed by SMLP or any of its restricted subsidiaries (or the payment of which is guaranteed by SMLP or any of its restricted subsidiaries); (vii) failure by SMLP or any of its restricted subsidiaries to pay certain final judgments aggregating in excess of $20.0 million ; (viii) except as permitted by the indenture, any guarantee of the senior notes shall cease for any reason to be in full force and effect or any guarantor, or any person acting on behalf of any guarantor, shall deny or disaffirm its obligations under its guarantee of the senior notes; and (ix) certain events of bankruptcy, insolvency or reorganization described in the indenture. In the case of an event of default as described in the foregoing clause (ix), all outstanding 5.5% Senior Notes will become due and payable immediately without further action or notice. If any other event of default occurs and is continuing, the trustee or the holders of at least 25% in principal amount of the then outstanding 5.5% Senior Notes may declare all the 5.5% Senior Notes to be due and payable immediately. As of December 31, 2016 , we were in compliance with the covenants of the 5.5% Senior Notes and there were no defaults or events of default during the year ended December 31, 2016 . 7.5% Senior Notes . The 7.5% Senior Notes were sold within the United States only to qualified institutional buyers in reliance on Rule 144A under the Securities Act and outside the United States only to non-U.S. persons in reliance on Regulation S under the Securities Act. Effective as of April 7, 2014, all of the holders of our 7.5% Senior Notes exchanged their unregistered senior notes and the guarantees of those notes for registered notes and guarantees. The terms of the registered senior notes were substantially identical to the terms of the unregistered senior notes, except that the transfer restrictions, registration rights and provisions for additional interest relating to the unregistered senior notes did not apply to the registered senior notes. We paid interest on the 7.5% Senior Notes semi-annually in cash in arrears on January 1 and July 1 of each year. Debt issuance costs of $7.4 million were being amortized to interest expense over the life of the senior notes. The 7.5% Senior Notes were senior, unsecured obligations and ranked equally in right of payment with all of our then-existing senior obligations. The 7.5% Senior Notes were effectively subordinated in right of payment to all of our secured indebtedness, to the extent of the collateral securing such indebtedness. We used the proceeds from the issuance of the 7.5% Senior Notes to repay a portion of the balance outstanding under our Revolving Credit Facility. Subsequent to June 2016, in accordance with the terms of the indenture, the Co-Issuers could redeem all or part of the 7.5% Senior Notes at a redemption price of 105.625% (with the redemption premium declining ratably each year to 100.000% on and after July 1, 2019), plus accrued and unpaid interest, if any. The 7.5% Senior Notes indenture restricted SMLP’s and the Co-Issuers’ ability and the ability of certain of their subsidiaries to: (i) incur additional debt or issue preferred stock; (ii) make distributions, repurchase equity or redeem subordinated debt; (iii) make payments on subordinated indebtedness; (iv) create liens or other encumbrances; (v) make investments, loans or other guarantees; (vi) sell or otherwise dispose of a portion of their assets; (vii) engage in transactions with affiliates; and (viii) make acquisitions or merge or consolidate with another entity. These covenants were subject to a number of important exceptions and qualifications. As of December 31, 2016 , we were in compliance with the covenants for the 7.5% Senior Notes and there were no defaults or events of default during the year ended December 31, 2016 . SMP Holdings Credit Facility. SMP Holdings had a $250.0 million revolving credit facility (the "SMP Revolving Credit Facility") and a $200.0 million term loan (the "Term Loan" and, collectively with the SMP Revolving Credit Facility, the "SMP Holdings Credit Facility"). Because funding from the SMP Holdings Credit Facility was used to support the development of the 2016 Drop Down Assets, Summit Investments allocated the SMP Holdings Credit Facility to the Partnership during the common control period. Borrowings under the SMP Holdings Credit Facility incurred interest at LIBOR or a base rate (as defined in the credit agreement) plus an applicable margin. In March 2014, Summit Investments repaid the then-outstanding $100.0 million remaining balance on the Term Loan as well as $95.0 million then outstanding under the SMP Revolving Credit Facility. It wrote off $1.5 million of debt issuance costs in connection with these repayments. In May 2014, Summit Investments borrowed $400.0 million pursuant to the Term Loan accordion and in May 2015, it repaid the then-outstanding remaining balance of the Term Loan accordion and wrote off $0.7 million of debt issuance costs in connection therewith. The allocation of activity under the SMP Revolving Credit Facility ended concurrent with the closing of the 2016 Drop Down.

FINANCIAL INSTRUMENTS

FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
FINANCIAL INSTRUMENTS	FINANCIAL INSTRUMENTS Concentrations of Credit Risk. Financial instruments that potentially subject us to concentrations of credit risk consist of cash and cash equivalents and accounts receivable. We maintain our cash and cash equivalents in bank deposit accounts that frequently exceed federally insured limits. We have not experienced any losses in such accounts and do not believe we are exposed to any significant risk. Accounts receivable primarily comprise amounts due for the gathering, treating and processing services we provide to our customers and also the sale of natural gas liquids resulting from our processing services. This industry concentration has the potential to impact our overall exposure to credit risk, either positively or negatively, in that our customers may be similarly affected by changes in economic, industry or other conditions. We monitor the creditworthiness of our counterparties and can require letters of credit for receivables from counterparties that are judged to have substandard credit, unless the credit risk can otherwise be mitigated. Our top five customers or counterparties accounted for 62% of total accounts receivable at December 31, 2016 , compared with 68% as of December 31, 2015 . Fair Value. The carrying amount of cash and cash equivalents, accounts receivable and trade accounts payable reported on the balance sheet approximates fair value due to their short-term maturities. The Deferred Purchase Price Obligation's carrying value is its fair value because carrying value represents the present value of the payment expected to be made in 2020. Our calculation of the Deferred Purchase Price Obligation involves significant assumptions and judgments. Differing assumptions regarding any of these inputs could have a material effect on the ultimate cash payment and the Deferred Purchase Price Obligation. As such, its fair value measurement is classified as a non-recurring Level 3 measurement in the fair value hierarchy because our assumptions and judgments are not observable from objective sources (see Note 16). The Deferred Purchase Price Obligation represents our only Level 3 financial instrument fair value measurement. A rollforward of our Level 3 liability measured at fair value on a recurring basis follows. Year ended December 31, 2016 (In thousands) Level 3 liability, beginning of period $ — Addition 507,427 Change in fair value 55,854 Level 3 liability, end of period $ 563,281 A summary of the estimated fair value of our debt financial instruments follows. December 31, 2016 December 31, 2015 Carrying value Estimated fair value (Level 2) Carrying value Estimated fair value (Level 2) (In thousands) Summit Holdings Revolving Credit Facility $ 648,000 $ 648,000 $ 344,000 $ 344,000 Summit Holdings 5.5% Senior Notes ($300.0 million principal) 296,484 294,500 295,861 224,000 Summit Holdings 7.5% Senior Notes ($300.0 million principal) 295,817 316,000 294,909 257,000 SMP Holdings revolving credit facility (1) — — 115,000 115,000 SMP Holdings term loan (1) — — 217,500 217,500 __________ (1) Debt was allocated to the 2016 Drop Down Assets prior to the closing of the 2016 Drop Down but was retained by Summit Investments after close. The carrying value on the balance sheet of each revolving credit facility and the term loan is its fair value due to its floating interest rate. The fair value for the Senior Notes is based on an average of nonbinding broker quotes as of December 31, 2016 and 2015. The use of different market assumptions or valuation methodologies may have a material effect on the estimated fair value of the Senior Notes.

PARTNERS' CAPITAL

PARTNERS' CAPITAL	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
PARTNERS' CAPITAL	PARTNERS' CAPITAL A rollforward of the number of common limited partner, subordinated limited partner and General Partner units follows. Common Subordinated General Partner Total Units, January 1, 2014 29,079,866 24,409,850 1,091,453 54,581,169 Units issued in connection with the March Equity 2014 Offering 5,300,000 — — 5,408,337 Contribution from General Partner — — 108,337 108,337 Net units issued under SMLP LTIP 46,647 — 861 47,508 Units, December 31, 2014 34,426,513 24,409,850 1,200,651 60,037,014 Units issued in connection with the May 2015 Equity Offering 7,475,000 — — 7,475,000 Contribution from General Partner — — 152,551 152,551 Net units issued under SMLP LTIP 161,131 — 1,498 162,629 Units, December 31, 2015 42,062,644 24,409,850 1,354,700 67,827,194 Subordinated units conversion 24,409,850 (24,409,850 ) — — Units issued in connection with the September 2016 Equity Offering 5,500,000 — — 5,500,000 Contribution from General Partner — — 112,245 112,245 Net units issued under SMLP LTIP 138,627 — 4,242 142,869 Units, December 31, 2016 72,111,121 — 1,471,187 73,582,308 Unit Offerings. In March 2014, we completed an underwritten public offering of 10,350,000 common units at a price of $38.75 per unit, of which 5,300,000 common units were offered by the Partnership and 5,050,000 common units were offered by a subsidiary of Summit Investments, pursuant to an effective shelf registration statement on Form S-3 previously filed with the SEC. Concurrently, our General Partner made a capital contribution to maintain its approximate 2% general partner interest in SMLP. We used the proceeds from the primary offering and the General Partner capital contribution to fund a portion of the purchase of Red Rock Gathering. In September 2014, we completed a secondary underwritten public offering of 4,347,826 SMLP common units held by a subsidiary of Summit Investments pursuant to an effective shelf registration statement on Form S-3 previously filed with the SEC. We did not receive any proceeds from this offering. In May 2015, we completed an underwritten public offering of 6,500,000 common units at a price of $30.75 per unit pursuant to an effective shelf registration statement on Form S-3 previously filed with the SEC (the "May 2015 Equity Offering"). On May 22, 2015, the underwriters exercised in full their option to purchase an additional 975,000 common units from us at a price of $30.75 per unit. Concurrent with both transactions, our General Partner made a capital contribution to us to maintain its approximate 2% general partner interest. In September 2016, we completed an underwritten public offering of 5,500,000 common units at a price of $23.20 per unit pursuant to an effective shelf registration statement on Form S-3 previously filed with the SEC (the "September 2016 Equity Offering"). Following the September 2016 Equity Offering, our General Partner made a capital contribution to us to maintain its approximate 2% general partner interest. We used the net proceeds from the September 2016 Equity Offering to pay down our Revolving Credit Facility. In January 2017, we completed a secondary underwritten public offering of 4,000,000 SMLP common units held by a subsidiary of Summit Investments pursuant to an effective shelf registration statement on Form S-3 previously filed with the SEC. We did not receive any proceeds from this offering. Subordination. The subordination period ended in conjunction with the February 2016 distribution payment in respect of the fourth quarter of 2015 and the then-outstanding subordinated units converted to common units on a one -for-one basis. Prior to the end of the subordination period, the principal difference between our common units and subordinated units was that holders of the subordinated units were not entitled to receive any distribution of available cash until the common units had received the minimum quarterly distribution ("MQD") plus any arrearages in the payment of the MQD from prior quarters. Noncontrolling Interest. We have recorded Summit Investments' indirect retained ownership interest in OpCo and its subsidiaries as a noncontrolling interest in the consolidated financial statements. Summit Investments' Equity in Contributed Subsidiaries. Summit Investments' equity in contributed subsidiaries represents its position in the net assets of the 2016 Drop Down Assets, Polar and Divide, Red Rock Gathering and Bison Midstream that have been acquired by SMLP. The balance also reflects net income attributable to Summit Investments for the 2016 Drop Down Assets, Polar and Divide, Red Rock Gathering and Bison Midstream for the periods beginning on their respective acquisition dates by Summit Investments and ending on the dates they were acquired by the Partnership. Net income or loss was attributed to Summit Investments for: • the 2016 Drop Down Assets for the period from January 1, 2014 to March 3, 2016; • Polar and Divide for the period from January 1, 2014 to May 18, 2015; and • Red Rock Gathering for the period from January 1, 2014 to March 18, 2014. Although included in partners' capital, any net income or loss attributable to Summit Investments is excluded from the calculation of EPU. 2016 Drop Down . On March 3, 2016, we acquired the 2016 Drop Down Assets from a subsidiary of Summit Investments. We paid cash consideration of $360.0 million and recognized a Deferred Purchase Price Obligation of $507.4 million in exchange for Summit Investments' $1.11 billion net investment in the 2016 Drop Down Assets (see Note 16). In June 2016, we received a working capital adjustment of $0.6 million from a subsidiary of Summit Investments. We recognized a capital contribution from Summit Investments for the difference between (i) the net cash consideration paid and the Deferred Purchase Price Obligation and (ii) Summit Investments' net investment in the 2016 Drop Down Assets. The calculation of the capital contribution and its allocation to partners' capital follows (in thousands). Summit Investments' net investment in the 2016 Drop Down Assets $ 771,929 SMP Holdings borrowings allocated to 2016 Drop Down Assets and retained by Summit Investments 342,926 Acquired carrying value of 2016 Drop Down Assets $ 1,114,855 Deferred Purchase Price Obligation $ 507,427 Borrowings under Revolving Credit Facility 360,000 Working capital adjustment received from a subsidiary of Summit Investments (569 ) Total consideration paid and recognized by SMLP 866,858 Excess of acquired carrying value over consideration paid and recognized $ 247,997 Allocation of capital contribution: General partner interest $ 4,953 Common limited partner interest 243,044 Partners' capital contribution – excess of acquired carrying value over consideration paid and recognized $ 247,997 Polar and Divide Drop Down . On May 18, 2015, we acquired 100% of the membership interests in Polar Midstream and Epping from a subsidiary of Summit Investments. We paid total net cash consideration of $285.7 million in exchange for Summit Investments' $416.0 million net investment in Polar Midstream and Epping, including customary working capital and capital expenditures adjustments (see Note 16 for additional information). We recognized a capital contribution from Summit Investments for the difference between cash consideration paid and Summit Investments' net investment in Polar Midstream and Epping. The calculation of the capital contribution and its allocation to partners' capital follow (in thousands). Summit Investments' net investment in Polar Midstream and Epping $ 416,044 Total net cash consideration paid to a subsidiary of Summit Investments 285,677 Excess of acquired carrying value over consideration paid $ 130,367 Allocation of capital contribution: General partner interest $ 2,607 Common limited partner interest 80,079 Subordinated limited partner interest 47,681 Partners' capital contribution – excess of acquired carrying value over consideration paid $ 130,367 Red Rock Drop Down . On March 18, 2014, we acquired 100% of the membership interests in Red Rock Gathering from a subsidiary of Summit Investments. We paid total net cash consideration of $307.9 million (including working capital adjustments accrued in December 2014 and cash settled in February 2015) in exchange for Summit Investments' $241.8 million net investment in Red Rock Gathering. As a result of the excess of the purchase price over acquired carrying value of Red Rock Gathering, SMLP recognized a capital distribution to Summit Investments. The calculation of the capital distribution and its allocation to partners' capital follow (in thousands). Summit Investments' net investment in Red Rock Gathering $ 241,817 Total net cash consideration paid to a subsidiary of Summit Investments 307,941 Excess of consideration paid over acquired carrying value $ (66,124 ) Allocation of capital distribution: General partner interest $ (1,323 ) Common limited partner interest (37,910 ) Subordinated limited partner interest (26,891 ) Partners' capital distribution – excess of consideration paid over acquired carrying value $ (66,124 ) Cash Distribution Policy Our cash distribution policy, as expressed in our Partnership Agreement, may not be modified or repealed without amending our Partnership Agreement. Our Partnership Agreement requires that we distribute all of our available cash (as defined below) within 45 days after the end of each quarter to unitholders of record on the applicable record date. Our policy is to distribute to our unitholders an amount of cash each quarter that is equal to or greater than the MQD stated in our Partnership Agreement. General Partner Interest. Our General Partner is entitled to an equivalent percentage of all distributions that we make prior to our liquidation based on its respective general partner interest, up to a maximum of 2% . Our General Partner has the right, but not the obligation, to contribute a proportionate amount of capital to us to maintain its current general partner interest. Our General Partner's interest in our distributions will be reduced if we issue additional units in the future and our General Partner does not contribute a proportionate amount of capital to us to maintain its general partner interest immediately prior to the unit issuance. Minimum Quarterly Distribution. Our Partnership Agreement generally requires that we make a minimum quarterly distribution to the holders of our common units of $0.40 per unit, or $1.60 on an annualized basis, to the extent we have sufficient cash from our operations after the establishment of cash reserves and the payment of costs and expenses, including reimbursements of expenses to our General Partner. The amount of distributions paid under our policy is subject to fluctuations based on the amount of cash we generate from our business and the decision to make any distribution is determined by our General Partner, taking into consideration the terms of our Partnership Agreement. Definition of Available Cash. Available cash generally means, for any quarter, all cash on hand at the end of that quarter: • less the amount of cash reserves established by our General Partner at the date of determination of available cash for that quarter to: • provide for the proper conduct of our business (including reserves for our future capital expenditures and anticipated future debt service requirements); • comply with applicable law, any of our debt instruments or other agreements; or • provide funds for distributions to our unitholders and to our General Partner for any one or more of the next four quarters (provided that our General Partner may not establish cash reserves for distributions unless it determines that the establishment of reserves will not prevent us from distributing the minimum quarterly distribution on all common units and any cumulative arrearages on such common units for the current quarter); • plus, if our General Partner so determines, all or any portion of the cash on hand on the date of determination of available cash for the quarter resulting from working capital borrowings made subsequent to the end of such quarter. Cash Distributions Paid and Declared. We paid the following per-unit distributions during the years ended December 31: Year ended December 31, 2016 2015 2014 Per-unit annual distributions to unitholders $ 2.300 $ 2.270 $ 2.040 On January 26, 2017 , the Board of Directors of our General Partner declared a distribution of $ 0.575 per unit for the quarterly period ended December 31, 2016. This distribution, which totaled $ 44.5 million , was paid on February 14, 2017 to unitholders of record at the close of business on February 7, 2017 . We allocated the February 2017 distribution in accordance with the third target distribution level (see "Incentive Distribution Rights—Percentage Allocations of Available Cash" below for additional information.) Incentive Distribution Rights. Our General Partner also currently holds IDRs that entitle it to receive increasing percentage allocations of the cash we distribute from operating surplus (as set forth in the chart below). The maximum distribution includes distributions paid to our General Partner on an assumed 2% general partner interest. The maximum distribution does not include any distributions that our General Partner may receive on any common units that it owns. Percentage Allocations of Available Cash . The following table illustrates the percentage allocations of available cash between the unitholders and our General Partner based on the specified target distribution levels. The amounts set forth in the column Marginal Percentage Interest in Distributions are the percentage interests of our General Partner and the unitholders in any available cash we distribute up to and including the corresponding amount in the column Total Quarterly Distribution Per Unit Target Amount. The percentage interests shown for our unitholders and our General Partner for the minimum quarterly distribution are also applicable to quarterly distribution amounts that are less than the MQD. The percentage interests set forth below for our General Partner assume (i) a 2% general partner interest, (ii) that our General Partner has not transferred its IDRs and (iii) that there are no arrearages on common units. Total quarterly distribution per unit target amount Marginal percentage interest in distributions Unitholders General Partner Minimum quarterly distribution $0.40 98% 2% First target distribution $0.40 up to $0.46 98% 2% Second target distribution above $0.46 up to $0.50 85% 15% Third target distribution above $0.50 up to $0.60 75% 25% Thereafter above $0.60 50% 50% We reached the second target distribution in connection with the distribution declared in respect of the fourth quarter of 2013. We reached the third target distribution in connection with the distribution declared in respect of the second quarter of 2014. Our payment of IDRs as reported in distributions to unitholders – General Partner in the statements of partners' capital during the years ended December 31 follow. Year ended December 31, 2016 2015 2014 (In thousands) IDR payments $ 7,912 $ 6,743 $ 2,326 For the purposes of calculating net income attributable to General Partner in the statements of operations and partners' capital, the financial impact of IDRs is recognized in respect of the quarter for which the distributions were declared. For the purposes of calculating distributions to unitholders in the statements of partners' capital and cash flows, IDR payments are recognized in the quarter in which they are paid.

EARNINGS PER UNIT

EARNINGS PER UNIT	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
EARNINGS PER UNIT	EARNINGS PER UNIT The following table details the components of EPU. Year ended December 31, 2016 2015 2014 (In thousands, except per-unit amounts) Numerator for basic and diluted EPU: Allocation of net loss among limited partner interests: Net loss attributable to common units $ (48,179 ) $ (125,437 ) $ (16,324 ) Net loss attributable to subordinated units (70,173 ) (10,793 ) Net loss attributable to limited partners $ (48,179 ) $ (195,610 ) $ (27,117 ) Denominator for basic and diluted EPU: Weighted-average common units outstanding – basic 68,264 39,217 33,311 Effect of nonvested phantom units — — — Weighted-average common units outstanding – diluted 68,264 39,217 33,311 Weighted-average subordinated units outstanding – basic and diluted 24,410 24,410 Loss per limited partner unit: Common unit – basic $ (0.71 ) $ (3.20 ) $ (0.49 ) Common unit – diluted $ (0.71 ) $ (3.20 ) $ (0.49 ) Subordinated unit – basic and diluted (1) $ (2.88 ) $ (0.44 ) Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU 125 109 232 __________ (1) The subordination period ended on February 16, 2016 and all 24,409,850 subordinated units converted to common units on a one-for-one basis (see Note 11).

UNIT-BASED AND NONCASH COMPENSA

UNIT-BASED AND NONCASH COMPENSATION	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
UNIT-BASED AND NONCASH COMPENSATION	UNIT-BASED AND NONCASH COMPENSATION SMLP Long-Term Incentive Plan. The SMLP LTIP provides for equity awards to eligible officers, employees, consultants and directors of our General Partner and its affiliates, thereby linking the recipients' compensation directly to SMLP’s performance. The SMLP LTIP is administered by our General Partner's Board of Directors, though such administration function may be delegated to a committee appointed by the board. A total of 5.0 million common units was reserved for issuance pursuant to and in accordance with the SMLP LTIP. As of December 31, 2016 , approximately 3.9 million common units remained available for future issuance. The SMLP LTIP provides for the granting, from time to time, of unit-based awards, including common units, restricted units, phantom units, unit options, unit appreciation rights, distribution equivalent rights, profits interest units and other unit-based awards. Grants are made at the discretion of the Board of Directors or Compensation Committee of our General Partner. The administrator of the SMLP LTIP may make grants under the SMLP LTIP that contain such terms, consistent with the SMLP LTIP, as the administrator may determine are appropriate, including vesting conditions. The administrator of the SMLP LTIP may, in its discretion, base vesting on the grantee's completion of a period of service or upon the achievement of specified financial objectives or other criteria or upon a change of control (as defined in the SMLP LTIP) or as otherwise described in an award agreement. Termination of employment prior to vesting will result in forfeiture of the awards, except in limited circumstances as described in the plan documents. Units that are canceled or forfeited will be available for delivery pursuant to other awards. The following table presents phantom and restricted unit activity: Units Weighted-average grant date fair value Nonvested phantom and restricted units, January 1, 2014 283,682 $ 23.41 Phantom units granted 136,867 42.32 Phantom and restricted units vested (61,917 ) 25.33 Phantom units forfeited (22,430 ) 25.56 Nonvested phantom units, December 31, 2014 336,202 30.61 Phantom units granted 289,735 29.21 Phantom units vested (229,497 ) 27.66 Phantom units forfeited (16,529 ) 35.09 Nonvested phantom units, December 31, 2015 379,911 31.13 Phantom units granted 495,535 14.91 Phantom units vested (178,953 ) 33.80 Phantom units forfeited (4,538 ) 16.89 Nonvested phantom units, December 31, 2016 691,955 $ 19.59 A phantom unit is a notional unit that entitles the grantee to receive a common unit upon the vesting of the phantom unit or on a deferred basis upon specified future dates or events or, in the discretion of the administrator, cash equal to the fair market value of a common unit. Distribution equivalent rights for each phantom unit provide for a lump sum cash amount equal to the accrued distributions from the grant date to be paid in cash upon the vesting date. A restricted unit is a common limited partner unit that is subject to a restricted period during which the unit remains subject to forfeiture. The phantom units granted in connection with the IPO vested on the third anniversary of the IPO. All other phantom units granted to date vest ratably over a three -year period. Grant date fair value is determined based on the closing price of our common units on the date of grant multiplied by the number of phantom units awarded to the grantee. Holders of all phantom units granted to date are entitled to receive distribution equivalent rights for each phantom unit, providing for a lump sum cash amount equal to the accrued distributions from the grant date of the phantom units to be paid in cash upon the vesting date. Upon vesting, phantom unit awards may be settled, at our discretion, in cash and/or common units, but the current intention is to settle all phantom unit awards with common units. The restricted units granted in 2013 maintained the vesting provisions of the share-based compensation awards they replaced, each of which had an original vesting period of four years. The intrinsic value of phantom and restricted units that vested during the years ended December 31, follows. Year ended December 31, 2016 2015 2014 (In thousands) Intrinsic value of vested LTIP awards $ 2,957 $ 5,362 $ 2,631 As of December 31, 2016 , the unrecognized unit-based compensation related to the SMLP LTIP was $5.4 million . Incremental unit-based compensation will be recorded over the remaining vesting period of approximately 2.2 years . Due to the limited and insignificant forfeiture history associated with the grants under the SMLP LTIP, no forfeitures were assumed in the determination of estimated compensation expense. Unit-based compensation recognized in general and administrative expense related to awards under the SMLP LTIP follows. Year ended December 31, 2016 2015 2014 (In thousands) SMLP LTIP unit-based compensation $ 7,550 $ 6,174 $ 4,696

RELATED-PARTY TRANSACTIONS

RELATED-PARTY TRANSACTIONS	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
RELATED-PARTY TRANSACTIONS	RELATED-PARTY TRANSACTIONS Acquisitions. See Notes 1, 9, 11 and 16 for disclosure of the 2016 Drop Down, Polar and Divide Drop Down, the Red Rock Drop Down and the funding of those transactions. Reimbursement of Expenses from General Partner. Our General Partner and its affiliates do not receive a management fee or other compensation in connection with the management of our business, but will be reimbursed for expenses incurred on our behalf. Under our Partnership Agreement, we reimburse our General Partner and its affiliates for certain expenses incurred on our behalf, including, without limitation, salary, bonus, incentive compensation and other amounts paid to our General Partner's employees and executive officers who perform services necessary to run our business. Our Partnership Agreement provides that our General Partner will determine in good faith the expenses that are allocable to us. Due to affiliate on the consolidated balance sheet represents the payables to our General Partner for expenses incurred by it and paid on our behalf. Expenses incurred by the General Partner and reimbursed by us under our Partnership Agreement were as follows: Year ended December 31, 2016 2015 2014 (In thousands) Operation and maintenance expense $ 26,485 $ 25,050 $ 22,004 General and administrative expense 31,947 26,193 24,993 Expenses Incurred by Summit Investments. Prior to the 2016 Drop Down, the Polar and Divide Drop Down and the Red Rock Drop Down, Summit Investments incurred: • certain support expenses and capital expenditures on behalf of the contributed subsidiaries. These transactions were settled periodically through membership interests prior to the respective drop down; • interest expense that was related to capital projects for the contributed subsidiaries. As such, the associated interest expense was allocated to the respective contributed subsidiary's capital projects as a noncash contribution and capitalized into the basis of the asset; and • noncash compensation expense for the SMP Net Profits Interests, which were accounted for as compensatory awards. As such, the annual expense associated with the SMP Net Profits was allocated to the respective contributed subsidiary and is reflected in general and administrative expenses in the statements of operations. Subsequent to any drop down, these expenses are retrospectively included in the reimbursement of General Partner expenses disclosed above due to common control.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Operating Leases. We and Summit Investments lease certain office space to support our operations. We have determined that our leases are operating leases. We recognize total rent expense incurred or allocated to us in general and administrative expenses. Rent expense related to operating leases, including rent expense incurred on our behalf and allocated to us, was as follows: Year ended December 31, 2016 2015 2014 (In thousands) Rent expense $ 2,861 $ 2,395 $ 1,881 We lease office space and equipment under agreements that expire in various years through 2021. Future minimum lease payments due under noncancelable operating leases at December 31, 2016, were as follows (in thousands): 2017 $ 3,512 2018 3,178 2019 2,520 2020 442 2021 34 Thereafter — Total future minimum lease payments $ 9,686 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. Environmental Matters. Although we believe that we are in material compliance with applicable environmental regulations, the risk of environmental remediation costs and liabilities are inherent in pipeline ownership and operation. Furthermore, we can provide no assurances that significant environmental remediation costs and liabilities will not be incurred by the Partnership in the future. We are currently not aware of any material contingent liabilities that exist with respect to environmental matters, except as noted below. In January 2015, Summit Investments learned of the rupture of a four-inch produced water gathering pipeline on the Meadowlark Midstream system near Williston, North Dakota. The rupture resulted in the release of some of the produced water in the pipeline. Based on Summit Investments' investigation and then-available information, it accounted for the rupture as a 2014 event. Summit Investments took action to minimize the impact of the rupture on affected landowners, control any environmental impact, help ensure containment and clean up the affected area. The incident, which was covered by Summit Investments' 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. Summit Investments exhausted the $25.0 million pollution liability policy in 2015. We submitted property and business interruption claim requests to the insurers and reached a settlement in January 2017. In connection therewith, we recognized $2.6 million of business interruption recoveries and $0.4 million of property recoveries. A rollforward of the aggregate accrued environmental remediation liabilities follows. Total (In thousands) Accrued environmental remediation, January 1, 2015 $ 30,000 Payments made by affiliates (13,136 ) Payments made with proceeds from insurance policies (25,000 ) Additional accruals 21,800 Accrued environmental remediation, December 31, 2015 13,664 Payments made, including those by affiliates (4,211 ) Accrued environmental remediation, December 31, 2016 $ 9,453 As of December 31, 2016, we have recognized (i) a current liability for remediation effort expenditures expected to be incurred within the next 12 months and (ii) a noncurrent liability for estimated remediation expenditures and fines expected to be incurred subsequent to December 31, 2017. Each of these amounts represent our best estimate for costs expected to be incurred. Neither of these amounts has been discounted to its present value. The U.S. Department of Justice has issued subpoenas to Summit Investments, Meadowlark Midstream, the Partnership and our General Partner requesting certain materials related to the rupture. We cannot predict the ultimate outcome of this matter with certainty for Summit Investments or Meadowlark Midstream, especially as it relates to any material liability as a result of any governmental proceeding related to the incident. SMLP and its General Partner did not have any management or operational control over, or ownership interest in, Meadowlark Midstream or the produced water disposal pipeline prior to the 2016 Drop Down. Furthermore, the Contribution Agreement executed in connection with the 2016 Drop Down contains customary representations and warranties and Summit Investments has agreed to indemnify the Partnership with respect to certain losses, including losses related to the rupture. As a result, we believe at this time that it is unlikely that SMLP or its General Partner will be subject to any material liability as a result of any governmental proceeding related to the rupture. In June 2015, Summit Investments and Meadowlark Midstream received a complaint from the North Dakota Industrial Commission seeking approximately $2.5 million in fines and other fees related to the rupture. Meadowlark Midstream has accrued its best estimate of the amount to be paid for such fines and other fees and intends to vigorously defend this complaint.

ACQUISITIONS AND DROP DOWN TRAN

ACQUISITIONS AND DROP DOWN TRANSACTIONS	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
ACQUISITIONS AND DROP DOWN TRANSACTIONS	ACQUISITIONS AND DROP DOWN TRANSACTIONS 2016 Drop Down. On March 3, 2016, SMLP acquired a controlling interest in OpCo, the entity which owns the 2016 Drop Down Assets. These assets include certain natural gas, crude oil and produced water gathering systems located in the Utica Shale, the Williston Basin and the DJ Basin as well as ownership interests in a natural gas gathering system and a condensate stabilization facility, both located in the Utica Shale. The net consideration paid and recognized in connection with the 2016 Drop Down (i) consisted of a cash payment to SMP Holdings of $360.0 million funded with borrowings under our Revolving Credit Facility and a $0.6 million working capital adjustment received in June 2016 (the “Initial Payment”) and (ii) includes the Deferred Purchase Price Obligation payment due in 2020. The Deferred Purchase Price Obligation will be equal to: • six-and-one-half ( 6.5 ) multiplied by the average Business Adjusted EBITDA, as defined below and in the Contribution Agreement, of the 2016 Drop Down Assets for 2018 and 2019, less the G&A Adjuster, as defined in the Contribution Agreement; • less the Initial Payment; • less all capital expenditures incurred for the 2016 Drop Down Assets between the March 3, 2016 and December 31, 2019; • plus all Business Adjusted EBITDA from the 2016 Drop Down Assets between March 3, 2016 and December 31, 2019, less the Cumulative G&A Adjuster, as defined in the Contribution Agreement. Business Adjusted EBITDA is defined as the net income or loss of the 2016 Drop Down Assets for such period: • plus interest expense, income tax expense and depreciation and amortization of the 2016 Drop Down Assets for such period; • plus any adjustments related to MVC shortfall payments, impairments and other noncash expenses or losses with respect to the 2016 Drop Down Assets for such period; • plus any Special Liability Expenses, as defined below and in the Contribution Agreement, for such period; • less interest income and income tax benefit of the 2016 Drop Down Assets for such period; • less adjustments related to any other noncash income or gains with respect to the 2016 Drop Down Assets for such period. Business Adjusted EBITDA shall exclude the effect of any Partnership expenses allocated by or to SMLP or its affiliates in respect of the 2016 Drop Down Assets, such as general and administrative expenses (including compensation-related expenses and professional services fees), transaction costs, allocated interest expense and allocated income tax expense. Special Liability Expenses are defined as any and all expenses incurred by SMLP with respect to the Special Liabilities, as defined in the Contribution Agreement, including fines, legal fees, consulting fees and remediation costs. The present value of the Deferred Purchase Price Obligation will be reflected as a liability on our balance sheet until paid. As of the acquisition date, the estimated future payment obligation (based on management’s estimate of the Partnership’s share of forecasted Business Adjusted EBITDA and capital expenditures for the 2016 Drop Down Assets) was estimated to be $860.3 million and had a net present value of $507.4 million , using a discount rate of 13% . As of December 31, 2016 , Remaining Consideration was estimated to be $830.3 million and the net present value, as recognized on the consolidated balance sheet, was $563.3 million , using a discount rate of 12% . Any subsequent changes to the estimated future payment obligation will be calculated using a discounted cash flow model with a commensurate risk-adjusted discount rate. Such changes and the impact on the liability due to the passage of time will be recorded as Deferred Purchase Price Obligation income or expense on the consolidated statements of operations in the period of the change. At the discretion of the Board of Directors of our General Partner, the Deferred Purchase Price Obligation can be paid in cash, SMLP common units or a combination thereof. We currently expect that the Deferred Purchase Price Obligation will be financed with a combination of (i) net proceeds from the sale of common units by us, (ii) the net proceeds from the issuance of senior unsecured debt by us, (iii) borrowings under our Revolving Credit Facility and/or (iv) other internally generated sources of cash. Because of the common control aspects in a drop down transaction, the 2016 Drop Down was deemed a transaction between entities under common control. As such, the 2016 Drop Down has been accounted for on an “as-if pooled” basis for all periods in which common control existed and the Partnership’s financial results retrospectively include the combined financial results of the 2016 Drop Down Assets for all common-control periods. Summit Utica . Summit Investments completed the acquisition of certain natural gas gathering assets located in the Utica Shale Play for $25.2 million on December 15, 2014. These assets, which were contributed to Summit Investments' then-newly formed subsidiary, Summit Utica, gather natural gas under a long-term, fee-based contract. Summit Investments accounted for the purchase under the acquisition method of accounting. We assigned the full purchase price to property, plant and equipment as of December 31, 2014. Ohio Gathering . For information on the acquisition and initial recognition of Ohio Gathering, see Note 7. Meadowlark Midstream . At the time of the 2016 Drop Down, Meadowlark Midstream owned Niobrara G&P and certain crude oil and produced water gathering pipelines located in Williams County, North Dakota. Summit Investments accounted for its purchase of Meadowlark Midstream under the acquisition method of accounting, whereby the various gathering systems' identifiable tangible and intangible assets acquired and liabilities assumed were recorded based on their fair values as of initial acquisition on February 15, 2013. Both Bison Midstream and Polar Midstream have previously been carved out of Meadowlark Midstream. Their fair values were determined based upon assumptions related to future cash flows, discount rates, asset lives and projected capital expenditures to complete the system. We recognized the 2016 acquisition of Meadowlark Midstream at Summit Investments' historical cost of construction and fair value of assets and liabilities at acquisition, which reflected its fair value accounting for the initial acquisition of Meadowlark Midstream in 2013, due to common control. The fair values of the assets acquired and liabilities assumed as of February 15, 2013, were as follows (in thousands): Purchase price assigned to Meadowlark Midstream $ 25,376 Current assets $ 2,227 Property, plant and equipment 18,795 Other noncurrent assets 4,354 Total assets acquired 25,376 Total liabilities assumed $ — Net identifiable assets acquired $ 25,376 From a financial position and operational standpoint, the crude oil and produced water gathering pipelines held by Meadowlark Midstream and acquired in connection with the 2016 Drop Down are recognized as part of the Polar and Divide system. Polar and Divide. On May 18, 2015, SMLP acquired the Polar and Divide system, a crude oil and produced water gathering system, including under-development transmission pipelines, located in North Dakota from a subsidiary of Summit Investments, subject to customary working capital and capital expenditures adjustments. We funded the initial combined purchase price of $290.0 million with (i) $92.0 million of borrowings under SMLP’s Revolving Credit Facility and (ii) the issuance of $193.4 million of SMLP common units and $4.1 million of general partner interests to SMLP’s General Partner in connection with the May 2015 Equity Offering. In July 2015, we received $4.3 million of cash from a subsidiary of Summit Investments as payment in full for working capital and capital expenditure adjustments. Summit Investments accounted for its purchase of Meadowlark Midstream, the entity that Polar Midstream was carved out of, under the acquisition method of accounting, whereby the various gathering systems' identifiable tangible and intangible assets acquired and liabilities assumed were recorded based on their fair values as of initial acquisition on February 15, 2013. Their fair values were determined based upon assumptions related to future cash flows, discount rates, asset lives and projected capital expenditures to complete the system. We recognized the acquisition of Polar Midstream at Summit Investments' historical cost of construction and fair value of assets and liabilities at acquisition, which reflected its fair value accounting for the acquisition of Meadowlark Midstream, due to common control. The fair values of the assets acquired and liabilities assumed as of February 15, 2013, were as follows (in thousands): Purchase price assigned to Polar Midstream $ 216,105 Current assets $ 368 Property, plant and equipment 9,755 Other noncurrent assets 7,201 Total assets acquired 17,324 Current liabilities 4,592 Total liabilities assumed $ 4,592 Net identifiable assets acquired 12,732 Goodwill $ 203,373 We believe that the goodwill recorded represents the incremental value of future cash flow potential attributed to estimated future gathering services within the Williston Basin. Red Rock Gathering System. On March 18, 2014, SMLP acquired Red Rock Gathering, a natural gas gathering and processing system located in Colorado and Utah, from a subsidiary of Summit Investments, subject to customary working capital adjustments. In October 2012, Summit Investments acquired ETC Canyon Pipeline, LLC ("Canyon") and contributed the Canyon gathering and processing assets to Red Rock Gathering, a newly formed, wholly owned subsidiary of Summit Investments. The Partnership paid total cash consideration of $307.9 million , comprising $305.0 million at the date of acquisition and $2.9 million of working capital adjustments that were recognized in due to affiliate as of December 31, 2014 and settled in February 2015. The acquisition of Red Rock Gathering was funded with the net proceeds from an offering of common units in March 2014, $100.0 million of borrowings under our Revolving Credit Facility and cash on hand. Because of the common control aspects in the drop down transaction, the Red Rock Gathering acquisition was deemed a transaction between entities under common control and, as such, was accounted for on an “as-if pooled” basis for all periods in which common control existed. SMLP’s financial results retrospectively include Red Rock Gathering’s financial results for all periods ending after October 23, 2012, the date Summit Investments acquired its interests, and before March 18, 2014. In 2014, we identified and wrote off the balance associated with a working capital adjustment received after the purchase accounting measurement period closed for Summit Investments' acquisition of Red Rock Gathering. This write off was recognized as a $1.2 million increase to gathering services and other fees for the year ended December 31, 2014. Lonestar Assets. DFW Midstream completed the acquisition of certain natural gas gathering assets located in the Barnett Shale Play (the "Lonestar assets") from Texas Energy Midstream, L.P. ("TEM") for $10.9 million on September 30, 2014. The Lonestar assets gather natural gas under two long-term, fee-based contracts. SMLP accounted for the purchase under the acquisition method of accounting. As of September 30, 2014, we preliminarily assigned the full purchase price to property, plant and equipment. During the fourth quarter of 2014, we received additional information from TEM and finalized the purchase price allocation. Supplemental Disclosures – As-If Pooled Basis. As a result of accounting for our drop down transactions similar to a pooling of interests, our historical financial statements and those of the acquired drop down assets have been combined to reflect the historical operations, financial position and cash flows of the acquired drop down assets from the date common control began. Revenues and net income for the previously separate entities and the combined amounts, as presented in these consolidated financial statements follow. Year ended December 31, 2016 2015 2014 (In thousands) SMLP revenues $ 393,495 $ 358,046 $ 338,941 2016 Drop Down Assets revenues (1) 8,867 29,238 14,466 Polar and Divide revenues (1) — 13,273 22,449 Red Rock Gathering revenues (1) — — 11,313 Combined revenues $ 402,362 $ 400,557 $ 387,169 SMLP net loss $ (40,932 ) $ (192,212 ) $ (23,992 ) 2016 Drop Down Assets net income (loss) (1) 2,745 (35,419 ) (32,634 ) Polar and Divide net income (1) — 5,403 6,430 Red Rock Gathering net income (1) — — 2,828 Combined net loss $ (38,187 ) $ (222,228 ) $ (47,368 ) __________ (1) Results are fully reflected in SMLP's results of operations subsequent to closing the respective drop down.

CONDENSED CONSOLIDATING FINANCI

CONDENSED CONSOLIDATING FINANCIAL INFORMATION	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
CONDENSED CONSOLIDATING FINANCIAL INFORMATION	CONDENSED CONSOLIDATING FINANCIAL INFORMATION In July 2014 and June 2013, the Co-Issuers issued the Senior Notes. The Senior Notes are fully and unconditionally guaranteed, jointly and severally, on a senior unsecured basis by SMLP and the Guarantor Subsidiaries (see Note 9). The following supplemental condensed consolidating financial information reflects SMLP's separate accounts, the combined accounts of the Co-Issuers, the combined accounts of the Guarantor Subsidiaries, the combined accounts of the Non-Guarantor Subsidiaries and the consolidating adjustments for the dates and periods indicated. For purposes of the following consolidating information: • each of SMLP and the Co-Issuers account for their subsidiary investments, if any, under the equity method of accounting and • the balances and results of operations associated with the assets, liabilities and expenses that were carved out of Summit Investments and allocated to SMLP in connection with the 2016 Drop Down have been attributed to SMLP during the common control period. Condensed Consolidating Balance Sheets. Balance sheets as of December 31, 2016 and 2015 follow. December 31, 2016 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Assets Cash and cash equivalents $ 698 $ 51 $ 5,647 $ 1,032 $ — $ 7,428 Accounts receivable 53 — 89,584 7,727 — 97,364 Other current assets 1,526 — 2,328 455 — 4,309 Due from affiliate 14,896 38,013 369,995 — (422,904 ) — Total current assets 17,173 38,064 467,554 9,214 (422,904 ) 109,101 Property, plant and equipment, net 2,266 — 1,440,180 411,225 — 1,853,671 Intangible assets, net — — 396,930 24,522 — 421,452 Goodwill — — 16,211 — — 16,211 Investment in equity method investees — — — 707,415 — 707,415 Other noncurrent assets 1,993 5,198 138 — — 7,329 Investment in subsidiaries 2,132,757 3,347,393 — — (5,480,150 ) — Total assets $ 2,154,189 $ 3,390,655 $ 2,321,013 $ 1,152,376 $ (5,903,054 ) $ 3,115,179 Liabilities and Partners' Capital Trade accounts payable $ 978 $ — $ 9,901 $ 5,372 $ — $ 16,251 Accrued expenses 2,399 114 6,069 2,807 — 11,389 Due to affiliate 408,266 — — 14,896 (422,904 ) 258 Ad valorem taxes payable 16 — 9,717 855 — 10,588 Accrued interest — 17,483 — — — 17,483 Accrued environmental remediation — — — 4,301 — 4,301 Other current liabilities 6,718 — 3,798 955 — 11,471 Total current liabilities 418,377 17,597 29,485 29,186 (422,904 ) 71,741 Long-term debt — 1,240,301 — — — 1,240,301 Deferred Purchase Price Obligation 563,281 — — — — 563,281 Deferred revenue — — 57,465 — — 57,465 Noncurrent accrued environmental remediation — — — 5,152 — 5,152 Other noncurrent liabilities 2,858 — 4,602 106 — 7,566 Total liabilities 984,516 1,257,898 91,552 34,444 (422,904 ) 1,945,506 Total partners' capital 1,169,673 2,132,757 2,229,461 1,117,932 (5,480,150 ) 1,169,673 Total liabilities and partners' capital $ 2,154,189 $ 3,390,655 $ 2,321,013 $ 1,152,376 $ (5,903,054 ) $ 3,115,179 December 31, 2015 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Assets Cash and cash equivalents $ 73 $ 12,407 $ 6,930 $ 2,383 $ — $ 21,793 Accounts receivable — — 84,021 5,560 — 89,581 Other current assets 540 — 2,672 361 — 3,573 Due from affiliate 3,168 151,443 207,651 — (362,262 ) — Total current assets 3,781 163,850 301,274 8,304 (362,262 ) 114,947 Property, plant and equipment, net 1,178 — 1,462,623 348,982 — 1,812,783 Intangible assets, net — — 438,093 23,217 — 461,310 Goodwill — — 16,211 — — 16,211 Investment in equity method investees — — — 751,168 — 751,168 Other noncurrent assets 3,480 4,611 162 — — 8,253 Investment in subsidiaries 2,438,395 3,222,187 — — (5,660,582 ) — Total assets $ 2,446,834 $ 3,390,648 $ 2,218,363 $ 1,131,671 $ (6,022,844 ) $ 3,164,672 Liabilities and Partners' Capital Trade accounts payable $ 482 $ — $ 18,489 $ 21,837 $ — $ 40,808 Accrued expenses 1,478 — 4,832 466 — 6,776 Due to affiliate 360,243 — — 3,168 (362,262 ) 1,149 Deferred revenue — — 677 — — 677 Ad valorem taxes payable 9 — 9,881 381 — 10,271 Accrued interest — 17,483 — — — 17,483 Accrued environmental remediation — — — 7,900 — 7,900 Other current liabilities 3,080 — 2,573 868 — 6,521 Total current liabilities 365,292 17,483 36,452 34,620 (362,262 ) 91,585 Long-term debt 332,500 934,770 — — — 1,267,270 Deferred revenue — — 45,486 — — 45,486 Noncurrent accrued environmental remediation — — — 5,764 — 5,764 Other noncurrent liabilities 1,743 — 5,503 22 — 7,268 Total liabilities 699,535 952,253 87,441 40,406 (362,262 ) 1,417,373 Total partners' capital 1,747,299 2,438,395 2,130,922 1,091,265 (5,660,582 ) 1,747,299 Total liabilities and partners' capital $ 2,446,834 $ 3,390,648 $ 2,218,363 $ 1,131,671 $ (6,022,844 ) $ 3,164,672 Condensed Consolidating Statements of Operations. For the purposes of the following condensed consolidating statements of operations, we allocate general and administrative expenses recognized at the SMLP parent to the Guarantor Subsidiaries and Non-Guarantor Subsidiaries to reflect what those entities' results would have been had they operated on a stand-alone basis. Statements of operations for the years ended December 31, 2016, 2015 and 2014 follow. Year ended December 31, 2016 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Revenues: Gathering services and related fees $ — $ — $ 288,399 $ 57,562 $ — $ 345,961 Natural gas, NGLs and condensate sales — — 35,833 — — 35,833 Other revenues — — 18,225 2,343 — 20,568 Total revenues — — 342,457 59,905 — 402,362 Costs and expenses: Cost of natural gas and NGLs — — 27,421 — — 27,421 Operation and maintenance — — 84,632 10,702 — 95,334 General and administrative — — 43,612 8,798 — 52,410 Depreciation and amortization 580 — 98,891 12,768 — 112,239 Transaction costs 1,321 — — — — 1,321 Loss (gain) on asset sales, net — — 99 (6 ) — 93 Long-lived asset impairment — — 1,235 529 — 1,764 Total costs and expenses 1,901 — 255,890 32,791 — 290,582 Other income 116 — — — — 116 Interest expense (1,441 ) (62,369 ) — — — (63,810 ) Deferred Purchase Price Obligation expense (55,854 ) — — — — (55,854 ) (Loss) income before income taxes and loss from equity method investees (59,080 ) (62,369 ) 86,567 27,114 — (7,768 ) Income tax expense (75 ) — — — — (75 ) Loss from equity method investees — — — (30,344 ) — (30,344 ) Equity in earnings of consolidated subsidiaries 20,968 83,337 — — (104,305 ) — Net (loss) income $ (38,187 ) $ 20,968 $ 86,567 $ (3,230 ) $ (104,305 ) $ (38,187 ) Year ended December 31, 2015 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Revenues: Gathering services and related fees $ — $ — $ 310,830 $ 26,989 $ — $ 337,819 Natural gas, NGLs and condensate sales — — 42,079 — — 42,079 Other revenues — — 18,411 2,248 — 20,659 Total revenues — — 371,320 29,237 — 400,557 Costs and expenses: Cost of natural gas and NGLs — — 31,398 — — 31,398 Operation and maintenance — — 87,286 7,700 — 94,986 General and administrative — — 37,926 7,182 — 45,108 Depreciation and amortization 603 — 95,586 8,928 — 105,117 Transaction costs 1,342 — — — — 1,342 Environmental remediation — — — 21,800 — 21,800 Gain on asset sales, net — — (172 ) — — (172 ) Long-lived asset impairment — — 9,305 — — 9,305 Goodwill impairment — — 248,851 — — 248,851 Total costs and expenses 1,945 — 510,180 45,610 — 557,735 Other income 2 — — — — 2 Interest expense (10,494 ) (48,598 ) — — — (59,092 ) Loss before income taxes and loss from equity method investees (12,437 ) (48,598 ) (138,860 ) (16,373 ) — (216,268 ) Income tax benefit 603 — — — — 603 Loss from equity method investees — — — (6,563 ) — (6,563 ) Equity in earnings of consolidated subsidiaries (210,394 ) (161,796 ) — — 372,190 — Net loss $ (222,228 ) $ (210,394 ) $ (138,860 ) $ (22,936 ) $ 372,190 $ (222,228 ) Year ended December 31, 2014 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Revenues: Gathering services and related fees $ — $ — $ 255,211 $ 12,267 $ — $ 267,478 Natural gas, NGLs and condensate sales — — 97,094 — — 97,094 Other revenues — — 20,398 2,199 — 22,597 Total revenues — — 372,703 14,466 — 387,169 Costs and expenses: Cost of natural gas and NGLs — — 72,415 — — 72,415 Operation and maintenance — — 88,927 5,942 — 94,869 General and administrative — — 40,447 2,834 — 43,281 Depreciation and amortization 588 — 86,762 3,528 — 90,878 Transaction costs 2,985 — — — — 2,985 Environmental remediation — — — 5,000 — 5,000 Loss on asset sales, net — — 442 — — 442 Long-lived asset impairment — — 5,505 — — 5,505 Goodwill impairment — — 54,199 — — 54,199 Total costs and expenses 3,573 — 348,697 17,304 — 369,574 Other income — — 1,189 — — 1,189 Interest expense (8,417 ) (40,169 ) — — — (48,586 ) (Loss) income before income taxes and loss from equity method investees (11,990 ) (40,169 ) 25,195 (2,838 ) — (29,802 ) Income tax (expense) benefit (1,680 ) — 826 — — (854 ) Loss from equity method investees — — — (16,712 ) — (16,712 ) Equity in earnings of consolidated subsidiaries (33,698 ) 6,471 — — 27,227 — Net (loss) income $ (47,368 ) $ (33,698 ) $ 26,021 $ (19,550 ) $ 27,227 $ (47,368 ) Condensed Consolidating Statements of Cash Flows. Statements of cash flows for the years ended December 31, 2016, 2015 and 2014 follow. Year ended December 31, 2016 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Cash flows from operating activities: Net cash provided by (used in) operating activities $ 9,691 $ (58,254 ) $ 198,991 $ 80,067 $ — $ 230,495 Cash flows from investing activities: Capital expenditures (1,668 ) — (49,378 ) (91,673 ) — (142,719 ) Contributions to equity method investees — — — (31,582 ) — (31,582 ) Acquisitions of gathering systems from affiliate, net of acquired cash (359,431 ) — — — — (359,431 ) Other, net (394 ) — — — — (394 ) Advances to affiliates (15,697 ) (255,070 ) (150,775 ) — 421,542 — Net cash used in investing activities (377,190 ) (255,070 ) (200,153 ) (123,255 ) 421,542 (534,126 ) Cash flows from financing activities: Distributions to unitholders (167,504 ) — — — — (167,504 ) Borrowings under Revolving Credit Facility 12,000 508,300 — — — 520,300 Repayments under Revolving Credit Facility — (204,300 ) — — — (204,300 ) Debt issuance costs — (3,032 ) — — — (3,032 ) Proceeds from issuance of common units, net 125,233 — — — — 125,233 Contribution from General Partner 2,702 — — — — 2,702 Cash advance (to) from Summit Investments (from) to contributed subsidiaries, net (12,000 ) — — 24,214 — 12,214 Expenses paid by Summit Investments on behalf of contributed subsidiaries 3,030 — — 1,791 — 4,821 Other, net (1,182 ) — (121 ) 135 — (1,168 ) Advances from affiliates 405,845 — — 15,697 (421,542 ) — Net cash provided by (used in) financing activities 368,124 300,968 (121 ) 41,837 (421,542 ) 289,266 Net change in cash and cash equivalents 625 (12,356 ) (1,283 ) (1,351 ) — (14,365 ) Cash and cash equivalents, beginning of period 73 12,407 6,930 2,383 — 21,793 Cash and cash equivalents, end of period $ 698 $ 51 $ 5,647 $ 1,032 $ — $ 7,428 Year ended December 31, 2015 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Cash flows from operating activities: Net cash provided by (used in) operating activities $ 409 $ (46,716 ) $ 202,324 $ 35,358 $ — $ 191,375 Cash flows from investing activities: Capital expenditures (429 ) — (118,458 ) (153,338 ) — (272,225 ) Contributions to equity method investees — — — (86,200 ) — (86,200 ) Acquisitions of gathering systems from affiliate, net of acquired cash (288,618 ) — — — — (288,618 ) Other, net — — 323 — — 323 Advances to affiliates (2,589 ) (88,221 ) (110,003 ) — 200,813 — Net cash used in investing activities (291,636 ) (88,221 ) (228,138 ) (239,538 ) 200,813 (646,720 ) Cash flows from financing activities: Distributions to unitholders (152,074 ) — — — — (152,074 ) Borrowings under Revolving Credit Facility 180,000 187,000 — — — 367,000 Repayments under Revolving Credit Facility (100,000 ) (51,000 ) — — — (151,000 ) Repayments under term loan (182,500 ) — — — — (182,500 ) Debt issuance costs (135 ) (277 ) — — — (412 ) Proceeds from issuance of common units, net 221,977 — — — — 221,977 Contribution from General Partner 4,737 — — — — 4,737 Cash advance from Summit Investments to contributed subsidiaries, net 102,500 — 21,719 196,308 — 320,527 Expenses paid by Summit Investments on behalf of contributed subsidiaries 12,655 — 3,864 6,360 — 22,879 Other, net (1,615 ) — (192 ) — — (1,807 ) Advances from affiliates 198,224 — — 2,589 (200,813 ) — Net cash provided by financing activities 283,769 135,723 25,391 205,257 (200,813 ) 449,327 Net change in cash and cash equivalents (7,458 ) 786 (423 ) 1,077 — (6,018 ) Cash and cash equivalents, beginning of period 7,531 11,621 7,353 1,306 — 27,811 Cash and cash equivalents, end of period $ 73 $ 12,407 $ 6,930 $ 2,383 $ — $ 21,793 Year ended December 31, 2014 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Cash flows from operating activities: Net cash (used in) provided by operating activities $ (3,658 ) $ (30,689 ) $ 179,685 $ 7,615 $ — $ 152,953 Cash flows from investing activities: Capital expenditures (460 ) — (220,360 ) (122,560 ) — (343,380 ) Initial contribution to Ohio Gathering — — — (8,360 ) — (8,360 ) Acquisition of Ohio Gathering Option — — — (190,000 ) — (190,000 ) Option Exercise — — — (382,385 ) — (382,385 ) Contributions to equity method investees — — — (145,131 ) — (145,131 ) Acquisition of gathering systems — — (10,872 ) — — (10,872 ) Acquisitions of gathering systems from affiliate, net of acquired cash (305,000 ) — — — — (305,000 ) Other, net — — 325 — — 325 Advances to affiliates (183 ) (174,495 ) (47,271 ) — 221,949 — Net cash used in investing activities (305,643 ) (174,495 ) (278,178 ) (848,436 ) 221,949 (1,384,803 ) Year ended December 31, 2014 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Cash flows from financing activities: Distributions to unitholders (122,224 ) — — — — (122,224 ) Borrowings under Revolving Credit Facility 57,000 237,295 — — — 294,295 Repayments under Revolving Credit Facility (115,000 ) (315,295 ) — — — (430,295 ) Borrowings under term loan 400,000 — — — — 400,000 Repayments under term loan (100,000 ) — — — — (100,000 ) Debt issuance costs (3,003 ) (5,320 ) — — — (8,323 ) Proceeds from issuance of common units, net 197,806 — — — — 197,806 Contribution from General Partner 4,235 — — — — 4,235 Cash advance (to) from Summit Investments (from) to contributed subsidiaries, net (242,000 ) — 81,421 834,962 — 674,383 Expenses paid by Summit Investments on behalf of contributed subsidiaries 12,845 — 10,483 1,556 — 24,884 Issuance of senior notes — 300,000 — — — 300,000 Repurchase of equity-based compensation awards (228 ) — — — — (228 ) Other, net (656 ) — — — — (656 ) Advances from affiliates 221,766 — — 183 (221,949 ) — Net cash provided by financing activities 310,541 216,680 91,904 836,701 (221,949 ) 1,233,877 Net change in cash and cash equivalents 1,240 11,496 (6,589 ) (4,120 ) — 2,027 Cash and cash equivalents, beginning of period 6,291 125 13,942 5,426 — 25,784 Cash and cash equivalents, end of period $ 7,531 $ 11,621 $ 7,353 $ 1,306 $ — $ 27,811

UNAUDITED QUARTERLY FINANCIAL D

UNAUDITED QUARTERLY FINANCIAL DATA	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
UNAUDITED QUARTERLY FINANCIAL DATA	UNAUDITED QUARTERLY FINANCIAL DATA Summarized information on the consolidated results of operations for each of the quarters during the two-year period ended December 31, 2016 , follows. Quarter ended December 31, 2016 Quarter ended September 30, 2016 Quarter ended June 30, 2016 Quarter ended March 31, 2016 (In thousands, except per-unit amounts) Total revenues $ 127,083 $ 95,073 $ 89,635 $ 90,571 Net income (loss) attributable to SMLP $ 13,901 $ 1,922 $ (50,287 ) $ (6,454 ) Less net income (loss) and IDRs attributable to General Partner 2,379 2,137 935 1,810 Net income (loss) attributable to limited partners $ 11,522 $ (215 ) $ (51,222 ) $ (8,264 ) Earnings (loss) per limited partner unit: Common unit – basic $ 0.16 $ 0.00 $ (0.77 ) $ (0.12 ) Common unit – diluted $ 0.16 $ 0.00 $ (0.77 ) $ (0.12 ) Quarter ended December 31, 2015 Quarter ended September 30, 2015 Quarter ended June 30, 2015 Quarter ended March 31, 2015 (In thousands, except per-unit amounts) Total revenues (1) $ 112,414 $ 115,201 $ 86,855 $ 86,087 Net (loss) income attributable to SMLP (2)(3) $ (220,468 ) $ 23,604 $ 2,985 $ 1,667 Less net (loss) income and IDRs attributable to General Partner (2,469 ) 2,408 1,891 1,568 Net (loss) income attributable to limited partners $ (217,999 ) $ 21,196 $ 1,094 $ 99 (Loss) earnings per limited partner unit: Common unit – basic $ (3.28 ) $ 0.32 $ 0.05 $ 0.00 Common unit – diluted $ (3.28 ) $ 0.32 $ 0.05 $ 0.00 Subordinated unit – basic and diluted $ (3.28 ) $ 0.32 $ (0.03 ) $ 0.00 __________ (1) Retrospectively adjusted for the impact of the 2016 Drop Down, the Polar and Divide Drop Down and the reclassification of certain revenues for Bison Midstream. (2) In the quarter ended December 31, 2015, net loss attributable to SMLP includes $248.9 million of goodwill impairments and $1.6 million of long-lived asset impairments. (3) In the quarter ended September 30, 2015, net income attributable to SMLP includes $20.0 million of additional accruals for environmental remediation expenses and $7.7 million of long-lived asset impairments. The amounts for total revenues as originally filed on the respective 2015 quarterly reports on Form 10-Q have been retrospectively adjusted for the impact of the 2016 Drop Down, Polar and Divide Drop Down and reclassification of certain revenues for Bison Midstream. There was no impact on net income attributable to partners or EPU. A reconciliation of total revenues follows. Quarter ended September 30, 2015 Quarter ended June 30, 2015 Quarter ended March 31, 2015 (In thousands) Total revenues as originally reported $ 103,249 $ 77,274 $ 68,579 2016 Drop Down 8,644 5,911 4,870 Polar and Divide Drop Down — — 8,582 Bison revenue reclass 3,308 3,670 4,056 Total revenues $ 115,201 $ 86,855 $ 86,087

SUMMARY OF SIGNIFICANT ACCOUN25

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Basis of Presentation	Presentation and Consolidation. We prepare our consolidated financial statements in accordance with GAAP as established by the FASB. We make estimates and assumptions that affect the reported amounts of assets and liabilities at the balance sheet dates, including fair value measurements, the reported amounts of revenue and expense and the disclosure of contingencies. Although management believes these estimates are reasonable, actual results could differ from its estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents. Cash and cash equivalents include temporary cash investments with original maturities of three months or less.
Accounts Receivable	Accounts Receivable. Accounts receivable relate to gathering and other services provided to our customers and other counterparties. We evaluate the collectability of accounts receivable and the need for an allowance for doubtful accounts based on customer-specific facts and circumstances. To the extent we doubt the collectability of a specific customer or counterparty receivable, we recognize an allowance for doubtful accounts.
Other Current Assets	Other Current Assets. Other current assets primarily consist of the current portion of prepaid expenses that are charged to expense over the period of benefit or the life of the related contract.
Property, Plant and Equipment	Property, Plant and Equipment. We record property, plant and equipment at historical cost of construction or fair value of the assets at acquisition. We capitalize expenditures that extend the useful life of an asset or enhance its productivity or efficiency from its original design over the expected remaining period of use. For maintenance and repairs that do not add capacity or extend the useful life of an asset, we recognize expenditures as an expense as incurred. We capitalize project costs incurred during construction, including interest on funds borrowed to finance the construction of facilities, as construction in progress. To the extent that Summit Investments incurred interest expense related to capital projects of assets that have been acquired by the Partnership, the associated interest expense is allocated to the drop down assets as a noncash equity contribution and capitalized into the basis of the asset. We record depreciation on a straight-line basis over an asset’s estimated useful life. We base our estimates for useful life on various factors including age (in the case of acquired assets), manufacturing specifications, technological advances and historical data concerning useful lives of similar assets. Estimates of useful lives follow. Useful lives (In years) Gathering and processing systems and related equipment 30 Other 4-15 Construction in progress is depreciated consistent with its applicable asset class once it is placed in service. Land and line fill are not depreciated. We base an asset’s carrying value on estimates, assumptions and judgments for useful life and salvage value. Upon sale, retirement or other disposal, we remove the carrying value of an asset and its accumulated depreciation from our balance sheet and recognize the related gain or loss, if any. Accrued capital expenditures are reflected in trade accounts payable.
Asset Retirement Obligations	Asset Retirement Obligations. We record a liability for asset retirement obligations only if and when a future asset retirement obligation with a determinable life is identified. For identified asset retirement obligations, we then evaluate whether the expected date and related costs of retirement can be estimated. We have concluded that our gathering and processing assets have an indeterminate life because they are owned and will operate for an indeterminate period when properly maintained. Because we did not have sufficient information to reasonably estimate the amount or timing of such obligations and we have no current plan to discontinue use of any significant assets, we did not provide for any asset retirement obligations as of December 31, 2016 or 2015 .
Amortizing Intangibles	Amortizing Intangibles. Upon the acquisition of DFW Midstream, certain of its gas gathering contracts were deemed to have above-market pricing structures while another was deemed to have pricing that was below market. We have recognized the above-market contracts as favorable gas gathering contracts. We have recognized the below-market contract as the unfavorable gas gathering contract and included it in other noncurrent liabilities. We amortize these contracts using a straight-line method over the contract's estimated useful life. We define useful life as the period over which the contract is expected to contribute to our future cash flows. These contracts have original terms ranging from 10 years to 20 years. We recognize the amortization expense associated with these contracts in other revenues. We amortize all other gas gathering contracts, or contract intangibles, over the period of economic benefit based upon expected revenues over the life of the contract. The useful life of these contracts ranges from 10 years to 25 years. We recognize the amortization expense associated with these contracts in depreciation and amortization expense. We have rights-of-way associated with city easements and easements granted within existing rights-of-way. We amortize these intangible assets over the shorter of the contractual term of the rights-of-way or the estimated useful life of the gathering system. The contractual terms of the rights-of-way range from 20 years to 30 years. We recognize the amortization expense associated with rights-of-way assets in depreciation and amortization expense.
Goodwill	Goodwill. Goodwill represents consideration paid in excess of the fair value of the net identifiable assets acquired in a business combination. We evaluate goodwill for impairment annually on September 30. We also evaluate goodwill whenever events or circumstances indicate that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. We test goodwill for impairment using a two-step quantitative test. In the first step, we compare the fair value of the reporting unit to its carrying value, including goodwill. To estimate the fair value of the reporting units under step one, we utilize two valuation methodologies: the market approach and the income approach. Both of these approaches incorporate significant estimates and assumptions to calculate enterprise fair value for a reporting unit. The most significant estimates and assumptions inherent within these two valuation methodologies are: (i) determination of the weighted-average cost of capital; (ii) the selection of guideline public companies; (iii) market multiples; (iv) weighting of the income and market approaches; (v) growth rates; (vi) commodity prices; and (vi) the expected levels of throughput volume gathered. Changes in these and other assumptions could materially affect the estimated amount of fair value for any of our reporting units. If the reporting unit’s fair value exceeds its carrying amount, we conclude that the goodwill of the reporting unit has not been impaired and no further work is performed. If we determine that the reporting unit’s carrying value exceeds its fair value, we proceed to step two. In step two, we compare the carrying value of the reporting unit to its implied fair value. Significant estimates and assumptions utilized in the determination of a reporting unit's implied fair value are based on a variety of factors specific to a given reporting unit's individual assets and liabilities as well as market and industry considerations. If we determine that the carrying amount of a reporting unit's goodwill exceeds its implied fair value, we recognize the excess of the carrying value over the implied fair value as an impairment loss.
Equity Method Investments	Equity Method Investments. We account for investments in which we exercise significant influence using the equity method so long as we (i) do not control the investee and (ii) are not the primary beneficiary. We recognize these investments in investment in equity method investees in the accompanying consolidated balance sheets. We recognize our proportionate share of earnings or loss in net income on a one-month lag. We recognize an other-than-temporary impairment for losses in the value of equity method investees when evidence indicates that the carrying amount is no longer supportable. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the equity method investee to sustain an earnings capacity that would justify the carrying amount of the investment. A current fair value of an investment that is less than its carrying amount may indicate a loss in value of the investment. We evaluate our equity method investments whenever evidence exists that would indicate a need to assess the investment for potential impairment.
Other Noncurrent Assets	Other Noncurrent Assets. Other noncurrent assets primarily consist of external costs incurred in connection with the closing of our Revolving Credit Facility and related amendments. We capitalize and then amortize these debt issuance costs on a straight-line basis over the life of the respective debt instrument. We recognize amortization of Revolving Credit Facility debt issuance costs in interest expense.
Debt Issuance Costs	Debt Issuance Costs. Debt issuance costs, other than those associated with our Revolving Credit Facility, are reflected in the carrying value of the Senior Notes as an adjustment to the principal amount and amortized on a straight-line basis over the life of the respective debt instrument. We recognize Senior Notes debt issuance costs in interest expense.
Deferred Purchase Price Obligation	Deferred Purchase Price Obligation. We recognize a liability for the Deferred Purchase Price Obligation (as defined later) to reflect the expected value of the Remaining Consideration to be paid in 2020 for the acquisition of the 2016 Drop Down Assets. We estimate Remaining Consideration by summing the calculations of (i) actual capital expenditures incurred and Business Adjusted EBITDA (as defined later) recognized from the 2016 Drop Down Assets during the period since closing the 2016 Drop Down to the current balance sheet date and (ii) estimates of projected capital expenditures and Business Adjusted EBITDA related to the 2016 Drop Down Assets for periods subsequent to the respective balance sheet date until December 31, 2019. We discount the Remaining Consideration using a commensurate risk-adjusted discount rate and recognize the change in present value of the Remaining Consideration in earnings in the period of change. Our recognition of the change in present value of the Remaining Consideration in the consolidated statements of operations represents the change in present value, which comprises a time value of money concept, as well as (i) actual results from the 2016 Drop Down Assets and (ii) adjustments to projections and the expected value of the Remaining Consideration
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets. We test assets for impairment when events or circumstances indicate that the carrying value of a long-lived asset may not be recoverable. The carrying value of a long-lived asset (except goodwill) is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from its use and eventual disposition. If we conclude that an asset's carrying value will not be recovered through future cash flows, we recognize an impairment loss on the long-lived asset equal to the amount by which the carrying value exceeds its fair value. We determine fair value using either a market-based approach or an income-based approach. We discuss our policy for goodwill impairment above.
Derivative Contracts	Derivative Contracts. We have commodity price exposure related to our sale of the physical natural gas we retain from certain DFW Midstream system customers and our procurement of electricity to operate the DFW Midstream system's electric-drive compression assets. Our gas gathering agreements with certain DFW Midstream customers permit us to retain a certain quantity of natural gas that we gather to offset the power costs we incur to operate these electric-drive compression assets. We manage this direct exposure to natural gas and power prices through the use of forward power purchase contracts with wholesale power providers that require us to purchase a fixed quantity of power at a fixed heat rate based on prevailing natural gas prices based on the Waha Hub Index. Because we sell our retainage gas from these customers at prices that are based on the Waha Hub Index, we have effectively fixed the relationship between a portion of our compression electricity expense and natural gas retainage sales. Accounting standards related to derivative instruments and hedging activities allow for normal purchase or sale elections and hedge accounting designations, which generally eliminate or defer the requirement for mark-to-market recognition in net income and thus reduce the volatility of net income that can result from fluctuations in fair values. We have designated these contracts as normal under the normal purchase and sale exception under the accounting standards for derivatives. We do not enter into risk management contracts for speculative purposes.
Fair Value of Financial Instruments	Fair Value of Financial Instruments. The fair-value-measurement standard under GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The standard characterizes inputs used in determining fair value according to a hierarchy that prioritizes those inputs based upon the degree to which the inputs are observable. The three levels of the fair value hierarchy are as follows: • Level 1. Inputs represent quoted prices in active markets for identical assets or liabilities; • Level 2. Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly (for example, quoted market prices for similar assets or liabilities in active markets or quoted market prices for identical assets or liabilities in markets not considered to be active, inputs other than quoted prices that are observable for the asset or liability, or market-corroborated inputs); and • Level 3. Inputs that are not observable from objective sources, such as management’s internally developed assumptions used in pricing an asset or liability (for example, an internally developed present value of future cash flows model that underlies management's fair value measurement).
Commitments and Contingencies	Commitments and Contingencies. We record accruals for loss contingencies when we determine that it is probable that a liability has been incurred and that such economic loss can be reasonably estimated. Such determinations are subject to interpretations of current facts and circumstances, forecasts of future events and estimates of the financial impacts of such events. We recognize gain contingencies when their realization is assured beyond a reasonable doubt.
Noncontrolling Interest	Noncontrolling Interest. Noncontrolling interest represents the ownership interests of third-party entities in the net assets of our consolidated subsidiaries. For financial reporting purposes, we consolidate OpCo and its wholly owned subsidiaries with our wholly owned subsidiaries and the 1% ownership interest in OpCo is reflected as noncontrolling interest in partners' capital. We reflect changes in our ownership of OpCo as adjustments to noncontrolling interest.
Revenue Recognition	Revenue Recognition. We generate the majority of our revenue from the gathering, treating and processing services that we provide to our customers. We also generate revenue from our marketing of natural gas, NGLs and condensate. We realize revenues by receiving fees from our customers or by selling the residue natural gas, NGLs and condensate. We recognize revenue earned from fee-based gathering, treating and processing services in gathering services and related fees revenue. We also earn revenue from the sale of physical natural gas purchased from our customers under percentage-of-proceeds arrangements. These revenues are recognized in natural gas, NGLs and condensate sales with corresponding expense recognition for the producer's share of the proceeds in cost of natural gas and NGLs. We sell substantially all of the natural gas that we retain from certain DFW Midstream customers to offset the power expenses of the electric-driven compression on the DFW Midstream system. We also sell condensate retained from our gathering services at Grand River. Revenues from the retainage of natural gas and condensate are recognized in natural gas, NGLs and condensate sales; the associated expense is included in operation and maintenance expense. Certain customers reimburse us for costs we incur on their behalf. We record costs incurred and reimbursed by our customers on a gross basis, with the revenue component recognized in other revenues. We recognize revenue when all of the following criteria are met: (i) persuasive evidence of an exchange arrangement exists, (ii) delivery has occurred or services have been rendered, (iii) the price is fixed or determinable and (iv) collectability is reasonably assured. We provide gathering and/or processing services principally under contracts that contain one or more of the following arrangements: • Fee-based arrangements. Under fee-based arrangements, we receive a fee or fees for one or more of the following services (i) natural gas gathering, treating and/or processing and (ii) crude oil and/or produced water gathering. • Percent-of-proceeds arrangements. Under percent-of-proceeds arrangements, we generally purchase natural gas from producers at the wellhead, or other receipt points, gather the wellhead natural gas through our gathering system, treat the natural gas, process the natural gas and/or sell the natural gas to a third party for processing. We then remit to our producers an agreed-upon percentage of the actual proceeds received from sales of the residue natural gas and NGLs. Certain of these arrangements may also result in returning all or a portion of the residue natural gas and/or the NGLs to the producer, in lieu of returning sales proceeds. The margins earned are directly related to the volume of natural gas that flows through the system and the price at which we are able to sell the residue natural gas and NGLs. Certain of our gathering and processing agreements provide for a monthly, quarterly or annual MVC. Under these MVCs, our customers agree to ship and/or process a minimum volume of production on our gathering systems or to pay a minimum monetary amount over certain periods during the term of the MVC. A customer must make a shortfall payment to us at the end of the contracted measurement period if its actual throughput volumes are less than its MVC for that period. Certain customers are entitled to utilize shortfall payments to offset gathering fees in one or more subsequent contracted measurement periods to the extent that such customer's throughput volumes in a subsequent contracted measurement period exceed its MVC for that contracted measurement period. We recognize customer billings for obligations under their MVCs as revenue when the obligations are billable under the contract and the customer does not have the right to utilize shortfall payments to offset gathering or processing fees in excess of its MVCs in subsequent periods. We record customer billings for obligations under their MVCs as deferred revenue when the customer has the right to utilize shortfall payments to offset gathering or processing fees in subsequent periods. We recognize deferred revenue under these arrangements in revenue once all contingencies or potential performance obligations associated with the related volumes have either (i) been satisfied through the gathering or processing of future excess volume throughput, or (ii) expired (or lapsed) through the passage of time pursuant to the terms of the applicable gathering or processing agreement. We also recognize deferred revenue in revenues when it is determined that a given amount of MVC shortfall payments cannot be recovered by offsetting gathering or processing fees in subsequent contracted measurement periods. In making this determination, we consider both quantitative and qualitative facts and circumstances, including, but not limited to, contract terms, capacity of the associated pipeline or receipt point and/or expectations regarding future investment, drilling and production. We classify deferred revenue as a current liability for arrangements where the expiration of a customer's right to utilize shortfall payments is 12 months or less. We classify deferred revenue as noncurrent for arrangements where the expiration of the right to utilize shortfall payments and our estimate of its potential utilization is more than 12 months.
Unit-Based Compensation	Unit-Based Compensation. For awards of unit-based compensation, we determine a grant date fair value and recognize the related compensation expense in the statements of operations over the vesting period of the respective awards.
Income Taxes	Income Taxes. As a partnership, we are generally not subject to federal and state income taxes, except as noted below. However, our unitholders are individually responsible for paying federal and state income taxes on their share of our taxable income. Net income or loss for GAAP purposes may differ significantly from taxable income reportable to our unitholders as a result of differences between the tax basis and the GAAP basis of assets and liabilities and the taxable income allocation requirements under our Partnership Agreement. In general, legal entities that are chartered, organized or conducting business in the state of Texas are subject to a franchise tax (the "Texas Margin Tax"). The Texas Margin Tax has the characteristics of an income tax because it is determined by applying a tax rate to a tax base that considers both revenues and expenses. Our financial statements reflect provisions for these tax obligations.
Earnings or Loss Per Unit	Earnings or Loss Per Unit. We determine basic EPU by dividing the net income or loss that is attributed, in accordance with the net income and loss allocation provisions of our Partnership Agreement, to limited partners under the two-class method, after deducting (i) the 1% noncontrolling interest in OpCo (for periods subsequent to the 2016 Drop Down), (ii) any net income or loss of contributed subsidiaries that is attributable to Summit Investments, (iii) the General Partner's approximate 2% interest in net income or loss and (iv) any payment of IDRs, by the weighted-average number of limited partner units outstanding. Diluted EPU reflects the potential dilution that could occur if securities or other agreements to issue common units, such as unit-based compensation, were exercised, settled or converted into common units and included in the weighted-average number of units outstanding. When it is determined that potential common units resulting from an award subject to performance or market conditions should be included in the diluted EPU calculation, the impact is reflected by applying the treasury stock method.
Comprehensive Income or Loss	Comprehensive Income or Loss. Comprehensive income or loss is the same as net income or loss for all periods presented.
Environmental Matters	Environmental Matters. We are subject to various federal, state and local laws and regulations relating to the protection of the environment. Liabilities for loss contingencies, including environmental remediation costs, arising from claims, assessments, litigation, fines and penalties and other sources are charged to expense when it is probable that a liability has been incurred and the amount of the assessment and/or remediation can be reasonably estimated. We accrue for losses associated with environmental remediation obligations when such losses are probable and reasonably estimable. Such accruals are adjusted as further information develops or circumstances change. Recoveries of environmental remediation costs from other parties or insurers are recorded as assets when their realization is assured beyond a reasonable doubt.
Carve-Out Entities, Assets, Liabilities and Expenses and Allocation of Certain Liabilities in Drop Downs	Carve-Out Entities, Assets, Liabilities and Expenses. For drop down transactions involving entities that were carved out of other entities, the majority of the assets and liabilities allocated to the carve-out entity are specifically identified based on the original entity's existing divisional organization. Goodwill is allocated to the carve-out entity based on initial purchase accounting estimates. Revenues and depreciation and amortization are specifically identified based on the relationship of the carve-out entity to the original entity's existing divisional structure. Operation and maintenance and general and administrative expenses are allocated to the carve-out entity based on volume throughput. For drop down transactions involving assets, liabilities and expenses that were carved out of other entities, the majority of the assets and liabilities allocated to the carve-out are specifically identified based on the original entity's existing divisional organization. Depreciation and amortization are specifically identified based on the relationship of the carve-out entity to the original entity's existing divisional structure. General and administrative expenses are allocated to the carve-out entity based on an allocation of Summit Investments' consolidated expenses. Allocation of Certain Liabilities in Drop Downs. For drop down transactions involving assets for which their development was funded with debt incurred by Summit Investments or a subsidiary thereof, which was allocated to but not ultimately assumed by the Partnership and later replaced with bank borrowings or debt capital at the Partnership, we allocate a portion of that debt, net of debt issuance costs, to the drop down assets during the common control period. Interest expense is allocated and recognized during the common control period. Any outstanding debt balance or principal is included in the calculation of the excess or deficit of acquired carrying value relative to consideration paid and recognized.
Accounting Pronouncements	Recent Accounting Pronouncements. Accounting standard setters frequently issue new or revised accounting rules. We review new pronouncements to determine the impact, if any, on our financial statements. Accounting standards that have or could possibly have a material effect on our financial statements are discussed below. Recently Adopted Accounting Pronouncements . We have recently adopted the following accounting pronouncements: • ASU No. 2015-03 Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs ("ASU 2015-03"). Under ASU 2015-03, entities that have historically presented debt issuance costs as an asset, related to a recognized debt liability, will be required to present those costs as a direct deduction from the carrying amount of that debt liability. In August 2015, the FASB amended ASU 2015-03 to address the presentation and subsequent measurement of debt issuance costs related to line of credit (“LOC”) arrangements. The amendment permits an entity to defer and present debt issuance costs as an asset and subsequently amortize debt issuance costs ratably over the term of a LOC arrangement, regardless of whether there are outstanding borrowings under that LOC arrangement. This new standard became effective for fiscal years and interim periods within those years, beginning after December 15, 2015. The January 2016 adoption of this update resulted in a reclassification from other noncurrent assets to long-term debt of the debt issuance costs associated with our Senior Notes (see Note 9). Debt issuance costs associated with the Revolving Credit Facility will remain in other noncurrent assets. This standard had no impact on interest expense, net income or loss, EPU or partners' capital. • ASU No. 2016-15 Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force) ("ASU 2016-15"). ASU 2016-15 addresses how certain cash receipts and cash payments are presented and classified in the statements of cash flows. The applicable provisions relate to distributions received from equity method investees. ASU 2016-15 prescribes a method for differentiating between returns of investment (which should be classified as inflows from investing activities) and returns on investment (which should be classified as inflows from operating activities). With respect to distributions from equity method investees, entities make this determination by applying a cumulative-earnings approach or a nature of the distribution approach. The ASU formalizes each of these methods and allows an entity to choose either one as an accounting policy election. ASU 2016-15 is effective for public business entities for fiscal years beginning after December 15, 2017. Early adoption is permitted. The amendments in ASU 2016-15 are to be applied using a retrospective transition method to each period presented. We have adopted the provisions of ASU 2016-15 as of December 31, 2016 and have elected the nature of the distribution approach. The adoption of this standard had no impact on our financial statements. Accounting Pronouncements Pending Adoption . We are currently in the process of evaluating the applicability and/or impact of the following accounting pronouncements: • ASU No. 2014-09 Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09"). Under ASU 2014-09, revenue will be recognized under a five-step model: (i) identify the contract with the customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to performance obligations; and (v) recognize revenue when (or as) the performance obligation is satisfied. ASU 2014-09 is effective for fiscal years and interim periods within those years, beginning after December 15, 2017 and allows for early adoption. We expect to adopt the provisions of ASU 2014-09 effective January 1, 2018 using the modified retrospective method. We have substantially completed our review of our existing contracts under the new guidance. However, we are still assessing the financial statement impact of adoption for certain items discussed below. For contracts where we perform gathering services and earn a per-unit fee which is recognized at a point in time, revenue will be recognized over time as the service is performed, which is expected to accelerate the recognition of revenue by an immaterial amount. In addition, our contracts generally contain forms of what will be considered variable consideration, which will likely be constrained as the volumes are susceptible to factors outside of our control and influence. However, we will be billing amounts that correspond directly to the value transferred such that the resulting revenue recognized will be similar to current GAAP. Due to certain open technical issues, such as contributions in aid of construction and noncash consideration, as well as completion of our evaluations of MVCs, we cannot currently fully conclude on the impact of adoption. We anticipate that we will be able to complete our assessment of the impact of adoption by the end of the third quarter of 2017. • ASU No. 2016-02 Leases (Topic 842) ("ASU 2016-02"). ASU 2016-02 requires that lessees recognize all leases on the balance sheet, with the exception of short-term leases. A lease liability will be recorded for the obligation of a lessee to make lease payments arising from a lease. A right-of-use asset will be recorded which represents the lessee’s right to use, or to control the use of, a specified asset for a lease term. We are currently evaluating the impact of this guidance on lessor accounting but have made no determinations at this time. ASU 2016-02 is effective for public companies for fiscal years beginning after December 15, 2018, and requires the modified retrospective approach for transition. We are currently evaluating the provisions of ASU 2016-02 to determine its impact on our financial statements and related disclosures and expect to adopt its provisions effective January 1, 2019. • ASU No. 2016-08 Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) ("ASU 2016-08"). ASU 2016-08 does not change the core principle of Topic 606, rather it clarifies the implementation guidance on principal versus agent considerations. We expect to adopt the provisions of ASU 2016-08 effective January 1, 2018. Our position regarding the impact of and transition method for this update is the same as for ASU 2014-09. • ASU No. 2016-09 Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting ("ASU 2016-09"). ASU 2016-09 simplifies several aspects for share-based payment award transactions, including income tax consequences, the liability or equity classification of awards and classification on the statements of cash flows. ASU 2016-09 is effective for public companies for fiscal years beginning after December 15, 2016. It does not specify a single transition approach, rather it specifies retrospective, modified retrospective and/or prospective transition approaches based on the aspect being applied. As a partnership that is generally not subject to taxes, the primary impact of adopting ASU 2016-09 will be to change our classification of certain share-based payment awards activity in the statements of cash flows. • ASU No. 2016-10 Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing ("ASU 2016-10"). ASU 2016-10 clarifies the following two aspects of Topic 606 (i) identifying performance obligations and (ii) the licensing implementation guidance, while retaining the related principles for those areas. We expect to adopt the provisions of ASU 2016-10 effective January 1, 2018. Our position regarding the impact of and transition method for this update is the same as for ASU 2014-09. • ASU No. 2016-12 Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients ("ASU 2016-12"). ASU 2016-12 does not change the core principle of the guidance in Topic 606. Rather, the amendments therein affect only the narrow aspects of Topic 606 including assessing the collectability criterion and issues related to contract modification at transition and completed contracts at transition. We expect to adopt the provisions of ASU 2016-12 effective January 1, 2018. Our position regarding the impact of and transition method for this update is the same as for ASU 2014-09. •

SUMMARY OF SIGNIFICANT ACCOUN26

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Useful lives of Property, Plant and Equipment	Estimates of useful lives follow. Useful lives (In years) Gathering and processing systems and related equipment 30 Other 4-15 Details on property, plant and equipment follow. December 31, 2016 2015 (In thousands) Gathering and processing systems and related equipment $ 2,026,363 $ 1,883,139 Construction in progress 39,954 75,132 Land and line fill 11,442 11,055 Other 35,227 32,427 Total 2,112,986 2,001,753 Less accumulated depreciation 259,315 188,970 Property, plant and equipment, net $ 1,853,671 $ 1,812,783

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Schedule of assets by reportable segment	Assets by reportable segment follow. December 31, 2016 2015 2014 (In thousands) Assets: Utica Shale (1) $ 906,807 $ 886,224 $ 735,587 Williston Basin 724,084 740,361 861,461 Piceance/DJ Basins 843,440 866,095 941,382 Barnett Shale 404,314 416,586 428,935 Marcellus Shale 224,709 233,116 243,884 Total reportable segment assets 3,103,354 3,142,382 3,211,249 Corporate and other 12,294 22,290 31,213 Eliminations (469 ) — — Total assets $ 3,115,179 $ 3,164,672 $ 3,242,462 __________ (1) Represents the investment in equity method investees for Ohio Gathering (see Note 7) and total assets for Summit Utica.
Schedule of segment reporting information	Depreciation and amortization by reportable segment follows. Year ended December 31, 2016 2015 2014 (In thousands) Depreciation and amortization: Utica Shale (1) $ 4,331 $ 1,417 $ — Williston Basin 33,676 31,376 24,027 Piceance/DJ Basins 49,140 47,433 42,959 Barnett Shale (2) 16,093 16,392 16,601 Marcellus Shale 8,841 8,682 7,648 Total reportable segment depreciation and amortization 112,081 105,300 91,235 Corporate and other 580 603 587 Total depreciation and amortization $ 112,661 $ 105,903 $ 91,822 __________ (1) Excludes depreciation and amortization recognized by Ohio Gathering due to equity method accounting. (2) Includes the amortization expense associated with our favorable and unfavorable gas gathering contracts as reported in other revenues. Cash paid for capital expenditures by reportable segment follow. Year ended December 31, 2016 2015 2014 (In thousands) Cash paid for capital expenditures: Utica Shale (1) $ 78,708 $ 94,994 $ 24,787 Williston Basin 31,541 147,477 227,283 Piceance/DJ Basins 25,719 21,144 42,417 Barnett Shale 3,910 6,875 14,567 Marcellus Shale 1,173 1,306 33,866 Total reportable segment capital expenditures 141,051 271,796 342,920 Corporate and other 1,668 429 460 Total cash paid for capital expenditures $ 142,719 $ 272,225 $ 343,380 __________ (1) Excludes cash paid for capital expenditures by Ohio Gathering due to equity method accounting. Revenues by reportable segment follow. Year ended December 31, 2016 2015 2014 (In thousands) Revenues: Utica Shale (1) $ 24,263 $ 4,700 $ 190 Williston Basin 122,174 98,929 109,807 Piceance/DJ Basins 149,903 180,418 161,477 Barnett Shale 79,956 88,042 93,001 Marcellus Shale 26,111 28,468 22,694 Total reportable segments revenue 402,407 400,557 387,169 Corporate and other 412 — — Eliminations (457 ) — — Total revenues $ 402,362 $ 400,557 $ 387,169 __________ (1) Excludes revenues earned by Ohio Gathering due to equity method accounting.
Schedule of counterparties accounting for more than 10% of total revenues	Counterparties accounting for more than 10% of total revenues were as follows: Year ended December 31, 2016 2015 2014 Percentage of total revenues (1): Counterparty A - Piceance/DJ Basins 14 % 16 % 18 % Counterparty B - Piceance/DJ Basins * 14 % * __________ * Less than 10% (1) Total revenues include recognition of revenue during the year ended December 31, 2015 that was previously deferred in connection with certain MVCs (see Note 8).
Reconciliation of net income to adjusted EBITDA	Segment adjusted EBITDA by reportable segment follows. Year ended December 31, 2016 2015 2014 (In thousands) Reportable segment adjusted EBITDA: Utica Shale (1) $ 66,637 $ 35,873 $ 6,176 Williston Basin 79,475 34,008 30,009 Piceance/DJ Basins 109,241 110,222 110,763 Barnett Shale 54,634 59,526 60,528 Marcellus Shale 19,203 23,214 15,940 Total of reportable segments’ measures of profit or loss $ 329,190 $ 262,843 $ 223,416 __________ (1) Includes our proportional share of adjusted EBITDA for Ohio Gathering, based on a one-month lag. A reconciliation of loss before income taxes and loss from equity method investees to total of reportable segments' measures of profit or loss follows. Year ended December 31, 2016 2015 2014 (In thousands) Reconciliation of loss before income taxes and loss from equity method investees to total of reportable segments' measures of profit or loss: Loss before income taxes and loss from equity method investees $ (7,768 ) $ (216,268 ) $ (29,802 ) Add: Corporate and other 37,589 27,352 15,441 Interest expense 63,810 59,092 48,586 Deferred Purchase Price Obligation expense 55,854 — — Depreciation and amortization 112,661 105,903 91,822 Proportional adjusted EBITDA for equity method investees 45,602 33,667 6,006 Adjustments related to MVC shortfall payments 11,600 (11,902 ) 26,565 Unit-based and noncash compensation 7,985 7,017 5,841 Loss (gain) on asset sales, net 93 (172 ) 442 Long-lived asset impairment 1,764 9,305 5,505 Goodwill impairment — 248,851 54,199 Less: Interest income — 2 4 Impact of purchase price adjustment — — 1,185 Total of reportable segments' measures of profit or loss $ 329,190 $ 262,843 $ 223,416
Schedule of Adjustments Related to Minimum Volume Commitments Shortfall Payments	Adjustments related to MVC shortfall payments by reportable segment follow. Year ended December 31, 2016 Williston Basin Piceance/DJ Basins Barnett Shale Total (In thousands) Adjustments related to MVC shortfall payments: Net change in deferred revenue for MVC shortfall payments $ 8,691 $ 3,288 $ (677 ) $ 11,302 Expected MVC shortfall payments — (317 ) 615 298 Total adjustments related to MVC shortfall payments $ 8,691 $ 2,971 $ (62 ) $ 11,600 Year ended December 31, 2015 Williston Basin Piceance/DJ Basins Barnett Shale Total (In thousands) Adjustments related to MVC shortfall payments: Net change in deferred revenue for MVC shortfall payments $ 11,870 $ (21,623 ) $ (1,700 ) $ (11,453 ) Expected MVC shortfall payments — 33 (482 ) (449 ) Total adjustments related to MVC shortfall payments $ 11,870 $ (21,590 ) $ (2,182 ) $ (11,902 ) Year ended December 31, 2014 Williston Basin Piceance/DJ Basins Barnett Shale Total (In thousands) Adjustments related to MVC shortfall payments: Net change in deferred revenue for MVC shortfall payments $ 10,743 $ 14,813 $ 821 $ 26,377 Expected MVC shortfall payments — 381 (193 ) 188 Total adjustments related to MVC shortfall payments $ 10,743 $ 15,194 $ 628 $ 26,565

PROPERTY, PLANT, AND EQUIPMEN28

PROPERTY, PLANT, AND EQUIPMENT, NET (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Schedule of property, plant, and equipment, net	Estimates of useful lives follow. Useful lives (In years) Gathering and processing systems and related equipment 30 Other 4-15 Details on property, plant and equipment follow. December 31, 2016 2015 (In thousands) Gathering and processing systems and related equipment $ 2,026,363 $ 1,883,139 Construction in progress 39,954 75,132 Land and line fill 11,442 11,055 Other 35,227 32,427 Total 2,112,986 2,001,753 Less accumulated depreciation 259,315 188,970 Property, plant and equipment, net $ 1,853,671 $ 1,812,783
Schedule of long-lived asset impairments	For the assets which had fair values below their carrying value, we recognized the following long-lived asset impairments, by segment. Year ended December 31, 2016 2015 2014 (In thousands) Long-lived asset impairment: Williston Basin $ 569 $ 7,554 $ — Piceance/DJ Basins — 1,220 — Barnett Shale 1,195 531 5,505
Schedule of depreciation expense and capitalized interest	Depreciation expense and capitalized interest follow. Year ended December 31, 2016 2015 2014 (In thousands) Depreciation expense $ 70,770 $ 63,915 $ 53,064 Capitalized interest 3,709 3,372 4,646

AMORTIZING INTANGIBLE ASSETS 29

AMORTIZING INTANGIBLE ASSETS AND UNFAVORABLE GAS GATHERING CONTRACT (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets and liabilities subject to amortization	Details regarding our intangible assets and the unfavorable gas gathering contract (included in other noncurrent liabilities), all of which are subject to amortization, follow. December 31, 2016 Useful lives (In years) Gross carrying amount Accumulated amortization Net (Dollars in thousands) Favorable gas gathering contracts 18.7 $ 24,195 $ (10,795 ) $ 13,400 Contract intangibles 12.5 426,464 (146,468 ) 279,996 Rights-of-way 26.1 153,015 (24,959 ) 128,056 Total intangible assets $ 603,674 $ (182,222 ) $ 421,452 Unfavorable gas gathering contract 10.0 $ 10,962 $ (6,916 ) $ 4,046 December 31, 2015 Useful lives (In years) Gross carrying amount Accumulated amortization Net (Dollars in thousands) Favorable gas gathering contracts 18.7 $ 24,195 $ (9,534 ) $ 14,661 Contract intangibles 12.5 426,464 (111,052 ) 315,412 Rights-of-way 26.3 150,143 (18,906 ) 131,237 Total intangible assets $ 600,802 $ (139,492 ) $ 461,310 Unfavorable gas gathering contract 10.0 $ 10,962 $ (6,077 ) $ 4,885
Recognized amortization expense in other revenues and cost and expenses	We recognized amortization expense in other revenues as follows: Year ended December 31, 2016 2015 2014 (In thousands) Amortization expense – favorable gas gathering contracts $ (1,261 ) $ (1,478 ) $ (1,741 ) Amortization expense – unfavorable gas gathering contract 839 692 797 We recognized amortization expense in costs and expenses as follows: Year ended December 31, 2016 2015 2014 (In thousands) Amortization expense – contract intangibles $ 35,416 $ 35,339 $ 32,554 Amortization expense – rights-of-way 6,053 5,863 5,260
Estimated aggregate annual amortization expected to be recognized	The estimated aggregate annual amortization expected to be recognized as of December 31, 2016 for each of the five succeeding fiscal years follows. Intangible assets Unfavorable gas gathering contract (In thousands) 2017 $ 41,854 $ 2,158 2018 41,323 1,888 2019 41,154 — 2020 43,403 — 2021 41,630 —

GOODWILL (Tables)

GOODWILL (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Rollforward of goodwill by reportable segment	A rollforward of goodwill by reportable segment and in total follows. Piceance/DJ Basins Williston Basin Marcellus Shale Total (In thousands) Goodwill, January 1, 2015 $ 45,478 $ 203,373 $ 16,211 $ 265,062 Goodwill impairment (45,478 ) (203,373 ) — (248,851 ) Goodwill, December 31, 2015 — — 16,211 16,211 Goodwill impairment — — — — Goodwill, December 31, 2016 $ — $ — $ 16,211 $ 16,211 Accumulated goodwill impairments by reportable segment for those reporting units that have previously recognized goodwill follow. December 31, 2016 2015 2014 (In thousands) Accumulated goodwill impairment: Piceance/DJ Basins $ 45,478 $ 45,478 $ — Williston Basin 257,572 257,572 54,199 Total accumulated goodwill impairment $ 303,050 $ 303,050 $ 54,199

EQUITY METHOD INVESTMENTS (Tabl

EQUITY METHOD INVESTMENTS (Tables)	12 Months Ended
	Dec. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments	A reconciliation of our 40% ownership interest in Ohio Gathering to our investment per Ohio Gathering's books and records follows. 2016 2015 (In thousands) Investment in equity method investees, December 31 $ 707,415 $ 751,168 December cash distributions 3,172 3,472 December cash contributions (5,318 ) — Basis difference (143,536 ) (156,888 ) Investment in equity method investees, net of basis difference, November 30 $ 561,733 $ 597,752 Summarized balance sheet information for OGC and OCC follows (amounts represent 100% of investee financial information). November 30, 2016 November 30, 2015 OGC OCC OGC OCC (In thousands) Current assets $ 43,797 $ 2,546 $ 42,053 $ 6,633 Noncurrent assets 1,330,199 31,195 1,333,726 127,663 Total assets $ 1,373,996 $ 33,741 $ 1,375,779 $ 134,296 Current liabilities $ 22,067 $ 3,448 $ 34,996 $ 6,234 Noncurrent liabilities 8,396 13,111 5,538 12,545 Total liabilities $ 30,463 $ 16,559 $ 40,534 $ 18,779 Summarized statements of operations information for OGC and OCC follows (amounts represent 100% of investee financial information). Twelve months ended November 30, 2016 Twelve months ended November 30, 2015 Ten months ended November 30, 2014 OGC OCC OGC OCC OGC OCC (In thousands) Total revenues $ 148,662 $ 15,791 $ 120,623 $ 9,467 $ 45,313 $ — Total operating expenses 96,647 111,528 96,948 15,633 64,166 2,208 Net income (loss) 52,009 (94,230 ) 23,655 (6,852 ) (18,853 ) (2,208 )

DEFERRED REVENUE (Tables)

DEFERRED REVENUE (Tables)	12 Months Ended
	Dec. 31, 2016
Deferred Revenue Disclosure [Abstract]
Rollforward of deferred revenue	A rollforward of current deferred revenue follows. Williston Basin Piceance/DJ Basins Barnett Shale Total current (In thousands) Current deferred revenue, December 31, 2014 $ — $ — $ 2,377 $ 2,377 Additions — 2,743 677 3,420 Less revenue recognized — 2,743 2,377 5,120 Current deferred revenue, December 31, 2015 — — 677 677 Additions — 11,672 — 11,672 Less revenue recognized — 11,672 677 12,349 Current deferred revenue, December 31, 2016 $ — $ — $ — $ — A rollforward of noncurrent deferred revenue follows. Williston Basin Piceance/DJ Basins Barnett Shale Total noncurrent (In thousands) Noncurrent deferred revenue, December 31, 2014 $ 17,132 $ 38,107 $ — $ 55,239 Additions 11,897 12,765 — 24,662 Less revenue recognized 27 34,388 — 34,415 Noncurrent deferred revenue, December 31, 2015 29,002 16,484 — 45,486 Additions 8,691 3,700 — 12,391 Less revenue recognized — 412 — 412 Noncurrent deferred revenue, December 31, 2016 $ 37,693 $ 19,772 $ — $ 57,465

DEBT (Tables)

DEBT (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of debt and capital leases	Debt consisted of the following: December 31, 2016 2015 (In thousands) Summit Holdings variable rate senior secured Revolving Credit Facility (3.27% at December 31, 2016 and 2.93% at December 31, 2015) due November 2018 $ 648,000 $ 344,000 Summit Holdings 5.5% senior unsecured notes due August 2022 300,000 300,000 Less unamortized debt issuance costs (1) (3,516 ) (4,139 ) Summit Holdings 7.5% senior unsecured notes due July 2021 300,000 300,000 Less unamortized debt issuance costs (1) (4,183 ) (5,091 ) SMP Holdings variable rate senior secured revolving credit facility (2.43% at December 31, 2015) (2) — 115,000 SMP Holdings variable rate senior secured term loan (2.43% at December 31, 2015) (2) — 217,500 Total long-term debt $ 1,240,301 $ 1,267,270 __________ (1) Issuance costs are being amortized over the life of the notes. (2) Debt was allocated to the 2016 Drop Down Assets prior to the closing of the 2016 Drop Down but was retained by Summit Investments after close.
Schedule of maturities of long-term debt	The aggregate amount of debt maturing during each of the years after December 31, 2016 are as follow (in thousands): 2017 $ — 2018 648,000 2019 — 2020 — 2021 300,000 Thereafter 300,000 Total long-term debt $ 1,248,000

FINANCIAL INSTRUMENTS (Tables)

FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	A rollforward of our Level 3 liability measured at fair value on a recurring basis follows. Year ended December 31, 2016 (In thousands) Level 3 liability, beginning of period $ — Addition 507,427 Change in fair value 55,854 Level 3 liability, end of period $ 563,281
Summary of the estimated fair value of debt instruments	A summary of the estimated fair value of our debt financial instruments follows. December 31, 2016 December 31, 2015 Carrying value Estimated fair value (Level 2) Carrying value Estimated fair value (Level 2) (In thousands) Summit Holdings Revolving Credit Facility $ 648,000 $ 648,000 $ 344,000 $ 344,000 Summit Holdings 5.5% Senior Notes ($300.0 million principal) 296,484 294,500 295,861 224,000 Summit Holdings 7.5% Senior Notes ($300.0 million principal) 295,817 316,000 294,909 257,000 SMP Holdings revolving credit facility (1) — — 115,000 115,000 SMP Holdings term loan (1) — — 217,500 217,500 __________ (1) Debt was allocated to the 2016 Drop Down Assets prior to the closing of the 2016 Drop Down but was retained by Summit Investments after close.

PARTNERS' CAPITAL (Tables)

PARTNERS' CAPITAL (Tables)	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Schedule of partner units activity	A rollforward of the number of common limited partner, subordinated limited partner and General Partner units follows. Common Subordinated General Partner Total Units, January 1, 2014 29,079,866 24,409,850 1,091,453 54,581,169 Units issued in connection with the March Equity 2014 Offering 5,300,000 — — 5,408,337 Contribution from General Partner — — 108,337 108,337 Net units issued under SMLP LTIP 46,647 — 861 47,508 Units, December 31, 2014 34,426,513 24,409,850 1,200,651 60,037,014 Units issued in connection with the May 2015 Equity Offering 7,475,000 — — 7,475,000 Contribution from General Partner — — 152,551 152,551 Net units issued under SMLP LTIP 161,131 — 1,498 162,629 Units, December 31, 2015 42,062,644 24,409,850 1,354,700 67,827,194 Subordinated units conversion 24,409,850 (24,409,850 ) — — Units issued in connection with the September 2016 Equity Offering 5,500,000 — — 5,500,000 Contribution from General Partner — — 112,245 112,245 Net units issued under SMLP LTIP 138,627 — 4,242 142,869 Units, December 31, 2016 72,111,121 — 1,471,187 73,582,308
Schedule of Capital Distribution and Allocation to Partners	The calculation of the capital distribution and its allocation to partners' capital follow (in thousands). Summit Investments' net investment in Red Rock Gathering $ 241,817 Total net cash consideration paid to a subsidiary of Summit Investments 307,941 Excess of consideration paid over acquired carrying value $ (66,124 ) Allocation of capital distribution: General partner interest $ (1,323 ) Common limited partner interest (37,910 ) Subordinated limited partner interest (26,891 ) Partners' capital distribution – excess of consideration paid over acquired carrying value $ (66,124 ) The calculation of the capital contribution and its allocation to partners' capital follow (in thousands). Summit Investments' net investment in Polar Midstream and Epping $ 416,044 Total net cash consideration paid to a subsidiary of Summit Investments 285,677 Excess of acquired carrying value over consideration paid $ 130,367 Allocation of capital contribution: General partner interest $ 2,607 Common limited partner interest 80,079 Subordinated limited partner interest 47,681 Partners' capital contribution – excess of acquired carrying value over consideration paid $ 130,367 The calculation of the capital contribution and its allocation to partners' capital follows (in thousands). Summit Investments' net investment in the 2016 Drop Down Assets $ 771,929 SMP Holdings borrowings allocated to 2016 Drop Down Assets and retained by Summit Investments 342,926 Acquired carrying value of 2016 Drop Down Assets $ 1,114,855 Deferred Purchase Price Obligation $ 507,427 Borrowings under Revolving Credit Facility 360,000 Working capital adjustment received from a subsidiary of Summit Investments (569 ) Total consideration paid and recognized by SMLP 866,858 Excess of acquired carrying value over consideration paid and recognized $ 247,997 Allocation of capital contribution: General partner interest $ 4,953 Common limited partner interest 243,044 Partners' capital contribution – excess of acquired carrying value over consideration paid and recognized $ 247,997
Details of cash distributions	We paid the following per-unit distributions during the years ended December 31: Year ended December 31, 2016 2015 2014 Per-unit annual distributions to unitholders $ 2.300 $ 2.270 $ 2.040 Our payment of IDRs as reported in distributions to unitholders – General Partner in the statements of partners' capital during the years ended December 31 follow. Year ended December 31, 2016 2015 2014 (In thousands) IDR payments $ 7,912 $ 6,743 $ 2,326
Schedule of partnership target distributions	The following table illustrates the percentage allocations of available cash between the unitholders and our General Partner based on the specified target distribution levels. The amounts set forth in the column Marginal Percentage Interest in Distributions are the percentage interests of our General Partner and the unitholders in any available cash we distribute up to and including the corresponding amount in the column Total Quarterly Distribution Per Unit Target Amount. The percentage interests shown for our unitholders and our General Partner for the minimum quarterly distribution are also applicable to quarterly distribution amounts that are less than the MQD. The percentage interests set forth below for our General Partner assume (i) a 2% general partner interest, (ii) that our General Partner has not transferred its IDRs and (iii) that there are no arrearages on common units. Total quarterly distribution per unit target amount Marginal percentage interest in distributions Unitholders General Partner Minimum quarterly distribution $0.40 98% 2% First target distribution $0.40 up to $0.46 98% 2% Second target distribution above $0.46 up to $0.50 85% 15% Third target distribution above $0.50 up to $0.60 75% 25% Thereafter above $0.60 50% 50%

EARNINGS PER UNIT (Tables)

EARNINGS PER UNIT (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Schedule of earnings per limited partner unit	The following table details the components of EPU. Year ended December 31, 2016 2015 2014 (In thousands, except per-unit amounts) Numerator for basic and diluted EPU: Allocation of net loss among limited partner interests: Net loss attributable to common units $ (48,179 ) $ (125,437 ) $ (16,324 ) Net loss attributable to subordinated units (70,173 ) (10,793 ) Net loss attributable to limited partners $ (48,179 ) $ (195,610 ) $ (27,117 ) Denominator for basic and diluted EPU: Weighted-average common units outstanding – basic 68,264 39,217 33,311 Effect of nonvested phantom units — — — Weighted-average common units outstanding – diluted 68,264 39,217 33,311 Weighted-average subordinated units outstanding – basic and diluted 24,410 24,410 Loss per limited partner unit: Common unit – basic $ (0.71 ) $ (3.20 ) $ (0.49 ) Common unit – diluted $ (0.71 ) $ (3.20 ) $ (0.49 ) Subordinated unit – basic and diluted (1) $ (2.88 ) $ (0.44 ) Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU 125 109 232 __________ (1) The subordination period ended on February 16, 2016 and all 24,409,850 subordinated units converted to common units on a one-for-one basis (see Note 11).

UNIT-BASED AND NONCASH COMPEN37

UNIT-BASED AND NONCASH COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of activity	The following table presents phantom and restricted unit activity: Units Weighted-average grant date fair value Nonvested phantom and restricted units, January 1, 2014 283,682 $ 23.41 Phantom units granted 136,867 42.32 Phantom and restricted units vested (61,917 ) 25.33 Phantom units forfeited (22,430 ) 25.56 Nonvested phantom units, December 31, 2014 336,202 30.61 Phantom units granted 289,735 29.21 Phantom units vested (229,497 ) 27.66 Phantom units forfeited (16,529 ) 35.09 Nonvested phantom units, December 31, 2015 379,911 31.13 Phantom units granted 495,535 14.91 Phantom units vested (178,953 ) 33.80 Phantom units forfeited (4,538 ) 16.89 Nonvested phantom units, December 31, 2016 691,955 $ 19.59
Schedule of intrinsic values	The intrinsic value of phantom and restricted units that vested during the years ended December 31, follows. Year ended December 31, 2016 2015 2014 (In thousands) Intrinsic value of vested LTIP awards $ 2,957 $ 5,362 $ 2,631
Schedule of unit-based compensation recognized in general and administrative expense	Unit-based compensation recognized in general and administrative expense related to awards under the SMLP LTIP follows. Year ended December 31, 2016 2015 2014 (In thousands) SMLP LTIP unit-based compensation $ 7,550 $ 6,174 $ 4,696

RELATED-PARTY TRANSACTIONS (Tab

RELATED-PARTY TRANSACTIONS (Tables)	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Schedule of related party transactions	Expenses incurred by the General Partner and reimbursed by us under our Partnership Agreement were as follows: Year ended December 31, 2016 2015 2014 (In thousands) Operation and maintenance expense $ 26,485 $ 25,050 $ 22,004 General and administrative expense 31,947 26,193 24,993

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Schedule of total rent expense related to operating leases	Rent expense related to operating leases, including rent expense incurred on our behalf and allocated to us, was as follows: Year ended December 31, 2016 2015 2014 (In thousands) Rent expense $ 2,861 $ 2,395 $ 1,881
Future minimum lease payments due under noncancelable operating leases	Future minimum lease payments due under noncancelable operating leases at December 31, 2016, were as follows (in thousands): 2017 $ 3,512 2018 3,178 2019 2,520 2020 442 2021 34 Thereafter — Total future minimum lease payments $ 9,686
Schedule of accrued environmental remediation	A rollforward of the aggregate accrued environmental remediation liabilities follows. Total (In thousands) Accrued environmental remediation, January 1, 2015 $ 30,000 Payments made by affiliates (13,136 ) Payments made with proceeds from insurance policies (25,000 ) Additional accruals 21,800 Accrued environmental remediation, December 31, 2015 13,664 Payments made, including those by affiliates (4,211 ) Accrued environmental remediation, December 31, 2016 $ 9,453

ACQUISITIONS AND DROP DOWN TR40

ACQUISITIONS AND DROP DOWN TRANSACTIONS (Tables)	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Fair Value of Assets Acquired and Liabilities Assumed	The fair values of the assets acquired and liabilities assumed as of February 15, 2013, were as follows (in thousands): Purchase price assigned to Polar Midstream $ 216,105 Current assets $ 368 Property, plant and equipment 9,755 Other noncurrent assets 7,201 Total assets acquired 17,324 Current liabilities 4,592 Total liabilities assumed $ 4,592 Net identifiable assets acquired 12,732 Goodwill $ 203,373 The fair values of the assets acquired and liabilities assumed as of February 15, 2013, were as follows (in thousands): Purchase price assigned to Meadowlark Midstream $ 25,376 Current assets $ 2,227 Property, plant and equipment 18,795 Other noncurrent assets 4,354 Total assets acquired 25,376 Total liabilities assumed $ — Net identifiable assets acquired $ 25,376
Business Combination, Revenue and Net Income Disclosures	Revenues and net income for the previously separate entities and the combined amounts, as presented in these consolidated financial statements follow. Year ended December 31, 2016 2015 2014 (In thousands) SMLP revenues $ 393,495 $ 358,046 $ 338,941 2016 Drop Down Assets revenues (1) 8,867 29,238 14,466 Polar and Divide revenues (1) — 13,273 22,449 Red Rock Gathering revenues (1) — — 11,313 Combined revenues $ 402,362 $ 400,557 $ 387,169 SMLP net loss $ (40,932 ) $ (192,212 ) $ (23,992 ) 2016 Drop Down Assets net income (loss) (1) 2,745 (35,419 ) (32,634 ) Polar and Divide net income (1) — 5,403 6,430 Red Rock Gathering net income (1) — — 2,828 Combined net loss $ (38,187 ) $ (222,228 ) $ (47,368 ) __________ (1) Results are fully reflected in SMLP's results of operations subsequent to closing the respective drop down.

CONDENSED CONSOLIDATING FINAN41

CONDENSED CONSOLIDATING FINANCIAL INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Balance Sheet	Balance sheets as of December 31, 2016 and 2015 follow. December 31, 2016 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Assets Cash and cash equivalents $ 698 $ 51 $ 5,647 $ 1,032 $ — $ 7,428 Accounts receivable 53 — 89,584 7,727 — 97,364 Other current assets 1,526 — 2,328 455 — 4,309 Due from affiliate 14,896 38,013 369,995 — (422,904 ) — Total current assets 17,173 38,064 467,554 9,214 (422,904 ) 109,101 Property, plant and equipment, net 2,266 — 1,440,180 411,225 — 1,853,671 Intangible assets, net — — 396,930 24,522 — 421,452 Goodwill — — 16,211 — — 16,211 Investment in equity method investees — — — 707,415 — 707,415 Other noncurrent assets 1,993 5,198 138 — — 7,329 Investment in subsidiaries 2,132,757 3,347,393 — — (5,480,150 ) — Total assets $ 2,154,189 $ 3,390,655 $ 2,321,013 $ 1,152,376 $ (5,903,054 ) $ 3,115,179 Liabilities and Partners' Capital Trade accounts payable $ 978 $ — $ 9,901 $ 5,372 $ — $ 16,251 Accrued expenses 2,399 114 6,069 2,807 — 11,389 Due to affiliate 408,266 — — 14,896 (422,904 ) 258 Ad valorem taxes payable 16 — 9,717 855 — 10,588 Accrued interest — 17,483 — — — 17,483 Accrued environmental remediation — — — 4,301 — 4,301 Other current liabilities 6,718 — 3,798 955 — 11,471 Total current liabilities 418,377 17,597 29,485 29,186 (422,904 ) 71,741 Long-term debt — 1,240,301 — — — 1,240,301 Deferred Purchase Price Obligation 563,281 — — — — 563,281 Deferred revenue — — 57,465 — — 57,465 Noncurrent accrued environmental remediation — — — 5,152 — 5,152 Other noncurrent liabilities 2,858 — 4,602 106 — 7,566 Total liabilities 984,516 1,257,898 91,552 34,444 (422,904 ) 1,945,506 Total partners' capital 1,169,673 2,132,757 2,229,461 1,117,932 (5,480,150 ) 1,169,673 Total liabilities and partners' capital $ 2,154,189 $ 3,390,655 $ 2,321,013 $ 1,152,376 $ (5,903,054 ) $ 3,115,179 December 31, 2015 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Assets Cash and cash equivalents $ 73 $ 12,407 $ 6,930 $ 2,383 $ — $ 21,793 Accounts receivable — — 84,021 5,560 — 89,581 Other current assets 540 — 2,672 361 — 3,573 Due from affiliate 3,168 151,443 207,651 — (362,262 ) — Total current assets 3,781 163,850 301,274 8,304 (362,262 ) 114,947 Property, plant and equipment, net 1,178 — 1,462,623 348,982 — 1,812,783 Intangible assets, net — — 438,093 23,217 — 461,310 Goodwill — — 16,211 — — 16,211 Investment in equity method investees — — — 751,168 — 751,168 Other noncurrent assets 3,480 4,611 162 — — 8,253 Investment in subsidiaries 2,438,395 3,222,187 — — (5,660,582 ) — Total assets $ 2,446,834 $ 3,390,648 $ 2,218,363 $ 1,131,671 $ (6,022,844 ) $ 3,164,672 Liabilities and Partners' Capital Trade accounts payable $ 482 $ — $ 18,489 $ 21,837 $ — $ 40,808 Accrued expenses 1,478 — 4,832 466 — 6,776 Due to affiliate 360,243 — — 3,168 (362,262 ) 1,149 Deferred revenue — — 677 — — 677 Ad valorem taxes payable 9 — 9,881 381 — 10,271 Accrued interest — 17,483 — — — 17,483 Accrued environmental remediation — — — 7,900 — 7,900 Other current liabilities 3,080 — 2,573 868 — 6,521 Total current liabilities 365,292 17,483 36,452 34,620 (362,262 ) 91,585 Long-term debt 332,500 934,770 — — — 1,267,270 Deferred revenue — — 45,486 — — 45,486 Noncurrent accrued environmental remediation — — — 5,764 — 5,764 Other noncurrent liabilities 1,743 — 5,503 22 — 7,268 Total liabilities 699,535 952,253 87,441 40,406 (362,262 ) 1,417,373 Total partners' capital 1,747,299 2,438,395 2,130,922 1,091,265 (5,660,582 ) 1,747,299 Total liabilities and partners' capital $ 2,446,834 $ 3,390,648 $ 2,218,363 $ 1,131,671 $ (6,022,844 ) $ 3,164,672
Condensed Statement of Operations	Statements of operations for the years ended December 31, 2016, 2015 and 2014 follow. Year ended December 31, 2016 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Revenues: Gathering services and related fees $ — $ — $ 288,399 $ 57,562 $ — $ 345,961 Natural gas, NGLs and condensate sales — — 35,833 — — 35,833 Other revenues — — 18,225 2,343 — 20,568 Total revenues — — 342,457 59,905 — 402,362 Costs and expenses: Cost of natural gas and NGLs — — 27,421 — — 27,421 Operation and maintenance — — 84,632 10,702 — 95,334 General and administrative — — 43,612 8,798 — 52,410 Depreciation and amortization 580 — 98,891 12,768 — 112,239 Transaction costs 1,321 — — — — 1,321 Loss (gain) on asset sales, net — — 99 (6 ) — 93 Long-lived asset impairment — — 1,235 529 — 1,764 Total costs and expenses 1,901 — 255,890 32,791 — 290,582 Other income 116 — — — — 116 Interest expense (1,441 ) (62,369 ) — — — (63,810 ) Deferred Purchase Price Obligation expense (55,854 ) — — — — (55,854 ) (Loss) income before income taxes and loss from equity method investees (59,080 ) (62,369 ) 86,567 27,114 — (7,768 ) Income tax expense (75 ) — — — — (75 ) Loss from equity method investees — — — (30,344 ) — (30,344 ) Equity in earnings of consolidated subsidiaries 20,968 83,337 — — (104,305 ) — Net (loss) income $ (38,187 ) $ 20,968 $ 86,567 $ (3,230 ) $ (104,305 ) $ (38,187 ) Year ended December 31, 2015 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Revenues: Gathering services and related fees $ — $ — $ 310,830 $ 26,989 $ — $ 337,819 Natural gas, NGLs and condensate sales — — 42,079 — — 42,079 Other revenues — — 18,411 2,248 — 20,659 Total revenues — — 371,320 29,237 — 400,557 Costs and expenses: Cost of natural gas and NGLs — — 31,398 — — 31,398 Operation and maintenance — — 87,286 7,700 — 94,986 General and administrative — — 37,926 7,182 — 45,108 Depreciation and amortization 603 — 95,586 8,928 — 105,117 Transaction costs 1,342 — — — — 1,342 Environmental remediation — — — 21,800 — 21,800 Gain on asset sales, net — — (172 ) — — (172 ) Long-lived asset impairment — — 9,305 — — 9,305 Goodwill impairment — — 248,851 — — 248,851 Total costs and expenses 1,945 — 510,180 45,610 — 557,735 Other income 2 — — — — 2 Interest expense (10,494 ) (48,598 ) — — — (59,092 ) Loss before income taxes and loss from equity method investees (12,437 ) (48,598 ) (138,860 ) (16,373 ) — (216,268 ) Income tax benefit 603 — — — — 603 Loss from equity method investees — — — (6,563 ) — (6,563 ) Equity in earnings of consolidated subsidiaries (210,394 ) (161,796 ) — — 372,190 — Net loss $ (222,228 ) $ (210,394 ) $ (138,860 ) $ (22,936 ) $ 372,190 $ (222,228 ) Year ended December 31, 2014 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Revenues: Gathering services and related fees $ — $ — $ 255,211 $ 12,267 $ — $ 267,478 Natural gas, NGLs and condensate sales — — 97,094 — — 97,094 Other revenues — — 20,398 2,199 — 22,597 Total revenues — — 372,703 14,466 — 387,169 Costs and expenses: Cost of natural gas and NGLs — — 72,415 — — 72,415 Operation and maintenance — — 88,927 5,942 — 94,869 General and administrative — — 40,447 2,834 — 43,281 Depreciation and amortization 588 — 86,762 3,528 — 90,878 Transaction costs 2,985 — — — — 2,985 Environmental remediation — — — 5,000 — 5,000 Loss on asset sales, net — — 442 — — 442 Long-lived asset impairment — — 5,505 — — 5,505 Goodwill impairment — — 54,199 — — 54,199 Total costs and expenses 3,573 — 348,697 17,304 — 369,574 Other income — — 1,189 — — 1,189 Interest expense (8,417 ) (40,169 ) — — — (48,586 ) (Loss) income before income taxes and loss from equity method investees (11,990 ) (40,169 ) 25,195 (2,838 ) — (29,802 ) Income tax (expense) benefit (1,680 ) — 826 — — (854 ) Loss from equity method investees — — — (16,712 ) — (16,712 ) Equity in earnings of consolidated subsidiaries (33,698 ) 6,471 — — 27,227 — Net (loss) income $ (47,368 ) $ (33,698 ) $ 26,021 $ (19,550 ) $ 27,227 $ (47,368 )
Condensed Cash Flow Statement	Statements of cash flows for the years ended December 31, 2016, 2015 and 2014 follow. Year ended December 31, 2016 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Cash flows from operating activities: Net cash provided by (used in) operating activities $ 9,691 $ (58,254 ) $ 198,991 $ 80,067 $ — $ 230,495 Cash flows from investing activities: Capital expenditures (1,668 ) — (49,378 ) (91,673 ) — (142,719 ) Contributions to equity method investees — — — (31,582 ) — (31,582 ) Acquisitions of gathering systems from affiliate, net of acquired cash (359,431 ) — — — — (359,431 ) Other, net (394 ) — — — — (394 ) Advances to affiliates (15,697 ) (255,070 ) (150,775 ) — 421,542 — Net cash used in investing activities (377,190 ) (255,070 ) (200,153 ) (123,255 ) 421,542 (534,126 ) Cash flows from financing activities: Distributions to unitholders (167,504 ) — — — — (167,504 ) Borrowings under Revolving Credit Facility 12,000 508,300 — — — 520,300 Repayments under Revolving Credit Facility — (204,300 ) — — — (204,300 ) Debt issuance costs — (3,032 ) — — — (3,032 ) Proceeds from issuance of common units, net 125,233 — — — — 125,233 Contribution from General Partner 2,702 — — — — 2,702 Cash advance (to) from Summit Investments (from) to contributed subsidiaries, net (12,000 ) — — 24,214 — 12,214 Expenses paid by Summit Investments on behalf of contributed subsidiaries 3,030 — — 1,791 — 4,821 Other, net (1,182 ) — (121 ) 135 — (1,168 ) Advances from affiliates 405,845 — — 15,697 (421,542 ) — Net cash provided by (used in) financing activities 368,124 300,968 (121 ) 41,837 (421,542 ) 289,266 Net change in cash and cash equivalents 625 (12,356 ) (1,283 ) (1,351 ) — (14,365 ) Cash and cash equivalents, beginning of period 73 12,407 6,930 2,383 — 21,793 Cash and cash equivalents, end of period $ 698 $ 51 $ 5,647 $ 1,032 $ — $ 7,428 Year ended December 31, 2015 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Cash flows from operating activities: Net cash provided by (used in) operating activities $ 409 $ (46,716 ) $ 202,324 $ 35,358 $ — $ 191,375 Cash flows from investing activities: Capital expenditures (429 ) — (118,458 ) (153,338 ) — (272,225 ) Contributions to equity method investees — — — (86,200 ) — (86,200 ) Acquisitions of gathering systems from affiliate, net of acquired cash (288,618 ) — — — — (288,618 ) Other, net — — 323 — — 323 Advances to affiliates (2,589 ) (88,221 ) (110,003 ) — 200,813 — Net cash used in investing activities (291,636 ) (88,221 ) (228,138 ) (239,538 ) 200,813 (646,720 ) Cash flows from financing activities: Distributions to unitholders (152,074 ) — — — — (152,074 ) Borrowings under Revolving Credit Facility 180,000 187,000 — — — 367,000 Repayments under Revolving Credit Facility (100,000 ) (51,000 ) — — — (151,000 ) Repayments under term loan (182,500 ) — — — — (182,500 ) Debt issuance costs (135 ) (277 ) — — — (412 ) Proceeds from issuance of common units, net 221,977 — — — — 221,977 Contribution from General Partner 4,737 — — — — 4,737 Cash advance from Summit Investments to contributed subsidiaries, net 102,500 — 21,719 196,308 — 320,527 Expenses paid by Summit Investments on behalf of contributed subsidiaries 12,655 — 3,864 6,360 — 22,879 Other, net (1,615 ) — (192 ) — — (1,807 ) Advances from affiliates 198,224 — — 2,589 (200,813 ) — Net cash provided by financing activities 283,769 135,723 25,391 205,257 (200,813 ) 449,327 Net change in cash and cash equivalents (7,458 ) 786 (423 ) 1,077 — (6,018 ) Cash and cash equivalents, beginning of period 7,531 11,621 7,353 1,306 — 27,811 Cash and cash equivalents, end of period $ 73 $ 12,407 $ 6,930 $ 2,383 $ — $ 21,793 Year ended December 31, 2014 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Cash flows from operating activities: Net cash (used in) provided by operating activities $ (3,658 ) $ (30,689 ) $ 179,685 $ 7,615 $ — $ 152,953 Cash flows from investing activities: Capital expenditures (460 ) — (220,360 ) (122,560 ) — (343,380 ) Initial contribution to Ohio Gathering — — — (8,360 ) — (8,360 ) Acquisition of Ohio Gathering Option — — — (190,000 ) — (190,000 ) Option Exercise — — — (382,385 ) — (382,385 ) Contributions to equity method investees — — — (145,131 ) — (145,131 ) Acquisition of gathering systems — — (10,872 ) — — (10,872 ) Acquisitions of gathering systems from affiliate, net of acquired cash (305,000 ) — — — — (305,000 ) Other, net — — 325 — — 325 Advances to affiliates (183 ) (174,495 ) (47,271 ) — 221,949 — Net cash used in investing activities (305,643 ) (174,495 ) (278,178 ) (848,436 ) 221,949 (1,384,803 ) Year ended December 31, 2014 SMLP Co-Issuers Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating adjustments Total (In thousands) Cash flows from financing activities: Distributions to unitholders (122,224 ) — — — — (122,224 ) Borrowings under Revolving Credit Facility 57,000 237,295 — — — 294,295 Repayments under Revolving Credit Facility (115,000 ) (315,295 ) — — — (430,295 ) Borrowings under term loan 400,000 — — — — 400,000 Repayments under term loan (100,000 ) — — — — (100,000 ) Debt issuance costs (3,003 ) (5,320 ) — — — (8,323 ) Proceeds from issuance of common units, net 197,806 — — — — 197,806 Contribution from General Partner 4,235 — — — — 4,235 Cash advance (to) from Summit Investments (from) to contributed subsidiaries, net (242,000 ) — 81,421 834,962 — 674,383 Expenses paid by Summit Investments on behalf of contributed subsidiaries 12,845 — 10,483 1,556 — 24,884 Issuance of senior notes — 300,000 — — — 300,000 Repurchase of equity-based compensation awards (228 ) — — — — (228 ) Other, net (656 ) — — — — (656 ) Advances from affiliates 221,766 — — 183 (221,949 ) — Net cash provided by financing activities 310,541 216,680 91,904 836,701 (221,949 ) 1,233,877 Net change in cash and cash equivalents 1,240 11,496 (6,589 ) (4,120 ) — 2,027 Cash and cash equivalents, beginning of period 6,291 125 13,942 5,426 — 25,784 Cash and cash equivalents, end of period $ 7,531 $ 11,621 $ 7,353 $ 1,306 $ — $ 27,811

UNAUDITED QUARTERLY FINANCIAL42

UNAUDITED QUARTERLY FINANCIAL DATA (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Quarterly summarized information on the consolidated results of operations	Summarized information on the consolidated results of operations for each of the quarters during the two-year period ended December 31, 2016 , follows. Quarter ended December 31, 2016 Quarter ended September 30, 2016 Quarter ended June 30, 2016 Quarter ended March 31, 2016 (In thousands, except per-unit amounts) Total revenues $ 127,083 $ 95,073 $ 89,635 $ 90,571 Net income (loss) attributable to SMLP $ 13,901 $ 1,922 $ (50,287 ) $ (6,454 ) Less net income (loss) and IDRs attributable to General Partner 2,379 2,137 935 1,810 Net income (loss) attributable to limited partners $ 11,522 $ (215 ) $ (51,222 ) $ (8,264 ) Earnings (loss) per limited partner unit: Common unit – basic $ 0.16 $ 0.00 $ (0.77 ) $ (0.12 ) Common unit – diluted $ 0.16 $ 0.00 $ (0.77 ) $ (0.12 ) Quarter ended December 31, 2015 Quarter ended September 30, 2015 Quarter ended June 30, 2015 Quarter ended March 31, 2015 (In thousands, except per-unit amounts) Total revenues (1) $ 112,414 $ 115,201 $ 86,855 $ 86,087 Net (loss) income attributable to SMLP (2)(3) $ (220,468 ) $ 23,604 $ 2,985 $ 1,667 Less net (loss) income and IDRs attributable to General Partner (2,469 ) 2,408 1,891 1,568 Net (loss) income attributable to limited partners $ (217,999 ) $ 21,196 $ 1,094 $ 99 (Loss) earnings per limited partner unit: Common unit – basic $ (3.28 ) $ 0.32 $ 0.05 $ 0.00 Common unit – diluted $ (3.28 ) $ 0.32 $ 0.05 $ 0.00 Subordinated unit – basic and diluted $ (3.28 ) $ 0.32 $ (0.03 ) $ 0.00 __________ (1) Retrospectively adjusted for the impact of the 2016 Drop Down, the Polar and Divide Drop Down and the reclassification of certain revenues for Bison Midstream. (2) In the quarter ended December 31, 2015, net loss attributable to SMLP includes $248.9 million of goodwill impairments and $1.6 million of long-lived asset impairments. (3) In the quarter ended September 30, 2015, net income attributable to SMLP includes $20.0 million of additional accruals for environmental remediation expenses and $7.7 million of long-lived asset impairments.
Retrospective adjustments from impact of acquisitions	A reconciliation of total revenues follows. Quarter ended September 30, 2015 Quarter ended June 30, 2015 Quarter ended March 31, 2015 (In thousands) Total revenues as originally reported $ 103,249 $ 77,274 $ 68,579 2016 Drop Down 8,644 5,911 4,870 Polar and Divide Drop Down — — 8,582 Bison revenue reclass 3,308 3,670 4,056 Total revenues $ 115,201 $ 86,855 $ 86,087

ORGANIZATION, BUSINESS OPERAT43

ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION (Details) - USD ($) $ in Millions	1 Months Ended				12 Months Ended
	Sep. 30, 2016	Feb. 29, 2016	May 31, 2015	Mar. 31, 2014	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
ORGANIZATION AND BUSINESS OPERATIONS
Common limited partner capital (in shares)					72,111,000		42,063,000
Other noncurrent assets | Accounting Standards Update 2015-03
ORGANIZATION AND BUSINESS OPERATIONS
Deferred loan costs							$ 9.2
Long-term debt | Accounting Standards Update 2015-03
ORGANIZATION AND BUSINESS OPERATIONS
Deferred loan costs							$ (9.2)
Summit Holdings
ORGANIZATION AND BUSINESS OPERATIONS
Cumulative percentage ownership in subsidiary					100.00%
SMP Holdings | Contributed Entities
ORGANIZATION AND BUSINESS OPERATIONS
Join venture interest		100.00%
SMP Holdings | OGC
ORGANIZATION AND BUSINESS OPERATIONS
Join venture interest		40.00%
Summit Holdings | DFW Midstream
ORGANIZATION AND BUSINESS OPERATIONS
Cumulative percentage ownership in subsidiary					100.00%
Drop Down Assets 2016 Acquisition
ORGANIZATION AND BUSINESS OPERATIONS
Ownership percentage by noncontrolling owners					1.00%	1.00%
Common units | SMP Holdings
ORGANIZATION AND BUSINESS OPERATIONS
Common limited partner capital (in shares)					29,854,581
General Partner
ORGANIZATION AND BUSINESS OPERATIONS
General partner interest	2.00%		2.00%	2.00%	2.00%
General Partner | Summit Investments | Summit Midstream Partners, LP
ORGANIZATION AND BUSINESS OPERATIONS
General partner interest					2.00%

SUMMARY OF SIGNIFICANT ACCOUN44

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 31, 2016
Gathering and processing systems and related equipment
Property, Plant and Equipment [Line Items]
Useful life	30 years
Other | Minimum
Property, Plant and Equipment [Line Items]
Useful life	4 years
Other | Maximum
Property, Plant and Equipment [Line Items]
Useful life	15 years

SUMMARY OF SIGNIFICANT ACCOUN45

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Amortizing Intangibles (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Favorable gas gathering contracts
Finite-Lived Intangible Assets [Line Items]
Useful lives (In years)	18 years 8 months 12 days	18 years 8 months 12 days
Favorable gas gathering contracts | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful lives (In years)	10 years
Favorable gas gathering contracts | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful lives (In years)	20 years
Other Gas Gathering Contract | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful lives (In years)	10 years
Other Gas Gathering Contract | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful lives (In years)	25 years
Rights-of-way
Finite-Lived Intangible Assets [Line Items]
Useful lives (In years)	26 years 1 month	26 years 3 months
Rights-of-way | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful lives (In years)	20 years
Rights-of-way | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful lives (In years)	30 years

SUMMARY OF SIGNIFICANT ACCOUN46

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Noncontrolling Interest (Details)	Dec. 31, 2016	Mar. 31, 2016
Drop Down Assets 2016 Acquisition
Entity Information [Line Items]
Ownership percentage by noncontrolling owners	1.00%	1.00%

SUMMARY OF SIGNIFICANT ACCOUN47

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Earnings or Loss Per Unit (Details)	1 Months Ended			12 Months Ended
	Sep. 30, 2016	May 31, 2015	Mar. 31, 2014	Dec. 31, 2016	Mar. 31, 2016
General Partner
Entity Information [Line Items]
General partner interest	2.00%	2.00%	2.00%	2.00%
Drop Down Assets 2016 Acquisition
Entity Information [Line Items]
Ownership percentage by noncontrolling owners				1.00%	1.00%

SEGMENT INFORMATION - Assets, R

SEGMENT INFORMATION - Assets, Revenues, Depreciation and Amortization, and Capital Expenditures by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Assets	$ 3,115,179				$ 3,164,672				$ 3,115,179	$ 3,164,672	$ 3,242,462
Revenues	127,083	$ 95,073	$ 89,635	$ 90,571	112,414	$ 115,201	$ 86,855	$ 86,087	402,362	400,557	387,169
Depreciation and amortization									112,661	105,903	91,822
Capital expenditures									142,719	272,225	343,380
Reportable Segments
Segment Reporting Information [Line Items]
Assets	3,103,354				3,142,382				3,103,354	3,142,382	3,211,249
Revenues									402,407	400,557	387,169
Depreciation and amortization									112,081	105,300	91,235
Capital expenditures									141,051	271,796	342,920
Reportable Segments | Utica Shale Segment
Segment Reporting Information [Line Items]
Assets	906,807				886,224				906,807	886,224	735,587
Revenues									24,263	4,700	190
Depreciation and amortization									4,331	1,417	0
Capital expenditures									78,708	94,994	24,787
Reportable Segments | Williston Basin
Segment Reporting Information [Line Items]
Assets	724,084				740,361				724,084	740,361	861,461
Revenues									122,174	98,929	109,807
Depreciation and amortization									33,676	31,376	24,027
Capital expenditures									31,541	147,477	227,283
Reportable Segments | Piceance/DJ Basins
Segment Reporting Information [Line Items]
Assets	843,440				866,095				843,440	866,095	941,382
Revenues									149,903	180,418	161,477
Depreciation and amortization									49,140	47,433	42,959
Capital expenditures									25,719	21,144	42,417
Reportable Segments | Barnett Shale
Segment Reporting Information [Line Items]
Assets	404,314				416,586				404,314	416,586	428,935
Revenues									79,956	88,042	93,001
Depreciation and amortization									16,093	16,392	16,601
Capital expenditures									3,910	6,875	14,567
Reportable Segments | Marcellus Shale
Segment Reporting Information [Line Items]
Assets	224,709				233,116				224,709	233,116	243,884
Revenues									26,111	28,468	22,694
Depreciation and amortization									8,841	8,682	7,648
Capital expenditures									1,173	1,306	33,866
Corporate
Segment Reporting Information [Line Items]
Assets	12,294				22,290				12,294	22,290	31,213
Revenues									412	0	0
Depreciation and amortization									580	603	587
Capital expenditures									1,668	429	460
Consolidating adjustments
Segment Reporting Information [Line Items]
Assets	$ (469)				$ 0				(469)	0	0
Revenues									$ (457)	$ 0	$ 0

SEGMENT INFORMATION - Concentra

SEGMENT INFORMATION - Concentration Risk (Details) - Revenue - Customer concentration	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Counterparty A - Piceance/DJ Basins
Segment Reporting Information [Line Items]
Concentration risk, percentage	14.00%	16.00%	18.00%
Counterparty B - Piceance/DJ Basins
Segment Reporting Information [Line Items]
Concentration risk, percentage		14.00%

SEGMENT INFORMATION - Adjusted

SEGMENT INFORMATION - Adjusted EBITDA by Reportable Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 329,190	$ 262,843	$ 223,416
Utica Shale Segment
Segment Reporting Information [Line Items]
Adjusted EBITDA	66,637	35,873	6,176
Williston Basin
Segment Reporting Information [Line Items]
Adjusted EBITDA	79,475	34,008	30,009
Piceance/DJ Basins
Segment Reporting Information [Line Items]
Adjusted EBITDA	109,241	110,222	110,763
Barnett Shale
Segment Reporting Information [Line Items]
Adjusted EBITDA	54,634	59,526	60,528
Marcellus Shale
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 19,203	$ 23,214	$ 15,940

SEGMENT INFORMATION - Reconcili

SEGMENT INFORMATION - Reconciliation of Net Income to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting [Abstract]
Loss before income taxes and loss from equity method investees			$ (7,768)	$ (216,268)	$ (29,802)
Add:
Corporate and other			37,589	27,352	15,441
Interest expense			63,810	59,092	48,586
Deferred Purchase Price Obligation expense			55,854	0	0
Depreciation and amortization			112,661	105,903	91,822
Proportional adjusted EBITDA for equity method investees			45,602	33,667	6,006
Adjustments related to MVC shortfall payments			11,600	(11,902)	26,565
Unit-based and noncash compensation			7,985	7,017	5,841
Loss (gain) on asset sales, net			93	(172)	442
Long-lived asset impairment	$ 1,600	$ 7,700	1,764	9,305	5,505
Goodwill impairment	$ 248,900		0	248,851	54,199
Less:
Interest income			0	2	4
Impact of purchase price adjustment			0	0	1,185
Total of reportable segments' measures of profit or loss			$ 329,190	$ 262,843	$ 223,416

SEGMENT INFORMATION - Schedule

SEGMENT INFORMATION - Schedule of Adjustments Related to Minimum Volume Commitments Shortfall Payments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net change in deferred revenue for MVC shortfall payments	$ 11,302	$ (11,453)	$ 26,377
Expected MVC shortfall payments	298	(449)	188
Total adjustments related to MVC shortfall payments	11,600	(11,902)	26,565
Williston Basin
Segment Reporting Information [Line Items]
Net change in deferred revenue for MVC shortfall payments	8,691	11,870	10,743
Expected MVC shortfall payments	0	0	0
Total adjustments related to MVC shortfall payments	8,691	11,870	10,743
Piceance/DJ Basins
Segment Reporting Information [Line Items]
Net change in deferred revenue for MVC shortfall payments	3,288	(21,623)	14,813
Expected MVC shortfall payments	(317)	33	381
Total adjustments related to MVC shortfall payments	2,971	(21,590)	15,194
Barnett Shale
Segment Reporting Information [Line Items]
Net change in deferred revenue for MVC shortfall payments	(677)	(1,700)	821
Expected MVC shortfall payments	615	(482)	(193)
Total adjustments related to MVC shortfall payments	$ (62)	$ (2,182)	$ 628

PROPERTY, PLANT, AND EQUIPMEN53

PROPERTY, PLANT, AND EQUIPMENT, NET (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 2,001,753		$ 2,112,986	$ 2,001,753
Less accumulated depreciation	188,970		259,315	188,970
Property, plant and equipment, net	1,812,783		1,853,671	1,812,783
Long-lived asset impairment	1,600	$ 7,700	1,764	9,305	$ 5,505
Depreciation expense			70,770	63,915	53,064
Capitalized interest			3,709	3,372	4,646
Williston Basin
Property, Plant and Equipment [Line Items]
Long-lived asset impairment			569	7,554	0
Piceance/DJ Basins
Property, Plant and Equipment [Line Items]
Long-lived asset impairment			0	1,220	0
Barnett Shale
Property, Plant and Equipment [Line Items]
Long-lived asset impairment			1,195	531	$ 5,505
Gathering and processing systems and related equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,883,139		2,026,363	1,883,139
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	75,132		39,954	75,132
Land and line fill
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	11,055		11,442	11,055
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 32,427		$ 35,227	$ 32,427

AMORTIZING INTANGIBLE ASSETS 54

AMORTIZING INTANGIBLE ASSETS AND UNFAVORABLE GAS GATHERING CONTRACT (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 603,674	$ 600,802
Accumulated amortization	(182,222)	(139,492)
Net	$ 421,452	$ 461,310
Noncurrent liability
Unfavorable gas gathering contract, useful lives	10 years	10 years
Unfavorable contract, gross carrying amount	$ 10,962	$ 10,962
Unfavorable gas gathering contract, accumulated amortization	(6,916)	(6,077)
Unfavorable gas gathering contract, Net	4,046	$ 4,885
Intangible assets
2,017	41,854
2,018	41,323
2,019	41,154
2,020	43,403
2,021	41,630
Unfavorable gas gathering contract
2,017	2,158
2,018	1,888
2,019	0
2,020	0
2,021	$ 0
Favorable gas gathering contracts
Finite-Lived Intangible Assets [Line Items]
Useful lives (In years)	18 years 8 months 12 days	18 years 8 months 12 days
Gross carrying amount	$ 24,195	$ 24,195
Accumulated amortization	(10,795)	(9,534)
Net	13,400	14,661
Amortization expense
Amortization expense	$ (1,261)	$ (1,478)	$ (1,741)
Contract intangibles
Finite-Lived Intangible Assets [Line Items]
Useful lives (In years)	12 years 6 months	12 years 6 months
Gross carrying amount	$ 426,464	$ 426,464
Accumulated amortization	(146,468)	(111,052)
Net	279,996	315,412
Amortization expense
Amortization expense	$ (35,416)	$ (35,339)	(32,554)
Rights-of-way
Finite-Lived Intangible Assets [Line Items]
Useful lives (In years)	26 years 1 month	26 years 3 months
Gross carrying amount	$ 153,015	$ 150,143
Accumulated amortization	(24,959)	(18,906)
Net	128,056	131,237
Amortization expense
Amortization expense	(6,053)	(5,863)	(5,260)
Unfavorable Gas Gathering Contract
Amortization expense
Amortization expense	$ 839	$ 692	$ 797

GOODWILL - Schedule of goodwill

GOODWILL - Schedule of goodwill (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Goodwill, beginning balance		$ 16,211	$ 265,062
Goodwill impairment	$ (248,900)	0	(248,851)	$ (54,199)
Goodwill, ending balance	16,211	16,211	16,211	265,062
Accumulated goodwill impairment	303,050	303,050	303,050	54,199
Piceance/DJ Basins
Goodwill [Roll Forward]
Goodwill, beginning balance		0	45,478
Goodwill impairment		0	(45,478)
Goodwill, ending balance	0	0	0	45,478
Accumulated goodwill impairment	45,478	45,478	45,478	0
Williston Basin
Goodwill [Roll Forward]
Goodwill, beginning balance		0	203,373
Goodwill impairment		0	(203,373)
Goodwill, ending balance	0	0	0	203,373
Accumulated goodwill impairment	257,572	257,572	257,572	54,199
Marcellus Shale
Goodwill [Roll Forward]
Goodwill, beginning balance		16,211	16,211
Goodwill impairment		0	0
Goodwill, ending balance	$ 16,211	$ 16,211	$ 16,211	$ 16,211

GOODWILL - Narrative (Details)

GOODWILL - Narrative (Details) - USD ($)	3 Months Ended		12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Goodwill impairment	$ 248,900,000		$ 0	$ 248,851,000	$ 54,199,000
Mountaineer Midstream
Segment Reporting Information [Line Items]
Goodwill impairment			0
Grand River, Mountaineer Midstream and Polar and Divide Reporting Units
Segment Reporting Information [Line Items]
Goodwill impairment					0
Polar and Divide
Segment Reporting Information [Line Items]
Goodwill impairment		$ 0
Williston Basin
Segment Reporting Information [Line Items]
Goodwill impairment			0	203,373,000
Piceance/DJ Basins
Segment Reporting Information [Line Items]
Goodwill impairment			$ 0	$ 45,478,000
Bison Midstream | Williston Basin
Segment Reporting Information [Line Items]
Goodwill impairment					$ 54,200,000

EQUITY METHOD INVESTMENTS - Nar

EQUITY METHOD INVESTMENTS - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended			12 Months Ended
	Jun. 30, 2016	May 31, 2014	Jan. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Acquisition of initial interest in Ohio Gathering				$ 0	$ 0	$ 190,000
OGC
Schedule of Equity Method Investments [Line Items]
Non-affiliated owners' interest percent		60.00%
Impairment of asset	$ 37,800
Summit Midstream Partners, LLC | OGC
Schedule of Equity Method Investments [Line Items]
Cost method ownership interest			1.00%
Ownership interest value			$ 190,000
Capital contribution			$ 8,400
Equity method potential ownership interest			40.00%
Equity method ownership interest		40.00%
Capital contributions true-ups		$ 326,600
Acquisition of initial interest in Ohio Gathering		50,400
Management fee		$ 5,400
Option value			$ 7,500
Principal Owner | OGC
Schedule of Equity Method Investments [Line Items]
Equity method ownership interest	40.00%			40.00%

EQUITY METHOD INVESTMENTS - Rol

EQUITY METHOD INVESTMENTS - Rollforward of the Investment in Equity Method Investees (Details) - USD ($) $ in Thousands	11 Months Ended		12 Months Ended
	Nov. 30, 2016	Nov. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Equity Method Investment [Roll Forward]
Investment in equity method investees, December 31			$ 707,415	$ 751,168
December cash distributions			44,991	34,641	$ 2,992
December cash contributions			(31,582)	(86,200)	(145,131)
Investment in equity method investees, net of basis difference, November 30	$ 751,168		751,168
Summit Midstream Partners, LLC | OGC
Equity Method Investment [Roll Forward]
Investment in equity method investees, December 31	561,733	$ 597,752		707,415	$ 751,168
December cash distributions	3,172	3,472
December cash contributions	(5,318)	0
Basis difference	(143,536)	(156,888)
Investment in equity method investees, net of basis difference, November 30	$ 707,415	$ 751,168	$ 707,415	$ 751,168

EQUITY METHOD INVESTMENTS - Bal

EQUITY METHOD INVESTMENTS - Balance Sheet Information (Details) - USD ($) $ in Thousands	Nov. 30, 2016	Nov. 30, 2015
OGC
Schedule of Equity Method Investments [Line Items]
Current assets	$ 43,797	$ 42,053
Noncurrent assets	1,330,199	1,333,726
Total assets	1,373,996	1,375,779
Current liabilities	22,067	34,996
Noncurrent liabilities	8,396	5,538
Total liabilities	30,463	40,534
OCC
Schedule of Equity Method Investments [Line Items]
Current assets	2,546	6,633
Noncurrent assets	31,195	127,663
Total assets	33,741	134,296
Current liabilities	3,448	6,234
Noncurrent liabilities	13,111	12,545
Total liabilities	$ 16,559	$ 18,779

EQUITY METHOD INVESTMENTS - Sta

EQUITY METHOD INVESTMENTS - Statements of Operations Information (Details) - USD ($) $ in Thousands	10 Months Ended	12 Months Ended
	Nov. 30, 2014	Nov. 30, 2016	Nov. 30, 2015
OGC
Schedule of Equity Method Investments [Line Items]
Total revenues	$ 45,313	$ 148,662	$ 120,623
Total operating expenses	64,166	96,647	96,948
Net income (loss)	(18,853)	52,009	23,655
OCC
Schedule of Equity Method Investments [Line Items]
Total revenues	0	15,791	9,467
Total operating expenses	2,208	111,528	15,633
Net income (loss)	$ (2,208)	$ (94,230)	$ (6,852)

DEFERRED REVENUE (Details)

DEFERRED REVENUE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Movement in Deferred Revenue [Roll Forward]
Current deferred revenue, beginning balance	$ 677	$ 2,377
Current deferred revenue, Additions	11,672	3,420
Current deferred revenue, Less revenue recognized	12,349	5,120
Current deferred revenue, ending balance	0	677
Noncurrent deferred revenue, beginning balance	45,486	55,239
Noncurrent deferred revenue, Additions	12,391	24,662
Noncurrent deferred revenue, Less revenue recognized	412	34,415
Noncurrent deferred revenue, ending balance	57,465	45,486
Williston Basin
Movement in Deferred Revenue [Roll Forward]
Current deferred revenue, beginning balance	0	0
Current deferred revenue, Additions	0	0
Current deferred revenue, Less revenue recognized	0	0
Current deferred revenue, ending balance	0	0
Noncurrent deferred revenue, beginning balance	29,002	17,132
Noncurrent deferred revenue, Additions	8,691	11,897
Noncurrent deferred revenue, Less revenue recognized	0	27
Noncurrent deferred revenue, ending balance	37,693	29,002
Piceance/DJ Basins
Movement in Deferred Revenue [Roll Forward]
Current deferred revenue, beginning balance	0	0
Current deferred revenue, Additions	11,672	2,743
Current deferred revenue, Less revenue recognized	11,672	2,743
Current deferred revenue, ending balance	0	0
Noncurrent deferred revenue, beginning balance	16,484	38,107
Noncurrent deferred revenue, Additions	3,700	12,765
Noncurrent deferred revenue, Less revenue recognized	412	34,388
Noncurrent deferred revenue, ending balance	19,772	16,484
Barnett Shale
Movement in Deferred Revenue [Roll Forward]
Current deferred revenue, beginning balance	677	2,377
Current deferred revenue, Additions	0	677
Current deferred revenue, Less revenue recognized	677	2,377
Current deferred revenue, ending balance	0	677
Noncurrent deferred revenue, beginning balance	0	0
Noncurrent deferred revenue, Additions	0	0
Noncurrent deferred revenue, Less revenue recognized	0	0
Noncurrent deferred revenue, ending balance	$ 0	$ 0

DEFERRED REVENUE - Narrative (D

DEFERRED REVENUE - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015
Deferred Revenue Arrangement [Line Items]
Recognition amount		$ 412	$ 34,415
Accounts receivable potentially used to offset fees		8,500
Piceance/DJ Basins
Deferred Revenue Arrangement [Line Items]
Recognition amount		412	$ 34,388
Piceance/DJ Basins | Gathering Services and Related Fees
Deferred Revenue Arrangement [Line Items]
Recognition amount	$ 34,400
Accrued Income Receivable
Deferred Revenue Arrangement [Line Items]
Shortfall payment billings included in accounts receivable		$ 46,000

DEBT - Components of Long-Term

DEBT - Components of Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Line of Credit Facility [Line Items]
Total long-term debt	$ 1,240,301	$ 1,267,270
Revolving credit facility
Line of Credit Facility [Line Items]
Revolving credit facility	$ 648,000	$ 344,000
Variable interest rate	3.27%	2.93%
Senior Notes | 5.5% Senior Notes
Line of Credit Facility [Line Items]
Unsecured notes	$ 300,000	$ 300,000
Deferred loan costs	$ (3,516)	(4,139)
Stated interest rate	5.50%
Senior Notes | 7.5% Senior Notes
Line of Credit Facility [Line Items]
Unsecured notes	$ 300,000	300,000
Deferred loan costs	$ (4,183)	(5,091)
Stated interest rate	7.50%
SMP Holdings | Revolving credit facility
Line of Credit Facility [Line Items]
Revolving credit facility	$ 0	$ 115,000
Variable interest rate		2.43%
SMP Holdings | Senior Secured Term Loan
Line of Credit Facility [Line Items]
Revolving credit facility	$ 0	$ 217,500
Variable rate		2.43%

DEBT - Maturities (Details)

DEBT - Maturities (Details) $ in Thousands	Dec. 31, 2016USD ($)
Debt
2,017	$ 0
2,018	648,000
2,019	0
2,020	0
2,021	300,000
Thereafter	300,000
Total long-term debt	$ 1,248,000

DEBT - Revolving Credit Facilit

DEBT - Revolving Credit Facility (Details)	1 Months Ended	12 Months Ended
	Feb. 29, 2016USD ($)	Dec. 31, 2016USD ($)	Jan. 31, 2016USD ($)	Dec. 31, 2015
Senior Notes
Line of Credit Facility [Line Items]
Debt defaults		$ 0
Senior Notes | Summit Holdings and Finance Corporation
Line of Credit Facility [Line Items]
Buy-back of debt, up to	$ 100,000,000
Revolving credit facility
Line of Credit Facility [Line Items]
Borrowing capacity	$ 1,250,000,000	1,250,000,000	$ 700,000,000
Accordion feature		$ 200,000,000
Total leverage ratio	5.5
Commitment fee on unused portion of the facility		0.50%
Interest rate at period end		3.27%		2.93%
Unused portion under the facility		$ 602,000,000
Maximum cumulative lease payment obligations allowable under terms of covenants		$ 30,000,000
Period that cumulative lease payment obligations may not exceed specified amount under terms of covenants		12 months
Trailing period used in calculating the ratio of EBITDA to net interest expense		12 months
Ratio of consolidated EBITDA to net interest expense (less than)		2.5
Trailing period used in calculating the ratio of total indebtedness to consolidated EBITDA		12 months
Ratio of total indebtedness to consolidated EBITDA		5
Ratio of total indebtedness to consolidated EBITDA, for a specified period following certain acquisitions		5.5
Period following certain acquisitions, for which higher ratio of total indebtedness to consolidated EBITDA is to be maintained		270 days
Upper limit		3.75
Debt defaults		$ 0
Revolving credit facility | LIBOR
Line of Credit Facility [Line Items]
Applicable margin		2.50%
Revolving credit facility | Minimum
Line of Credit Facility [Line Items]
Total leverage ratio		5
Commitment fee on unused portion of the facility		0.30%
Revolving credit facility | Minimum | ABR
Line of Credit Facility [Line Items]
Applicable margin		0.75%
Revolving credit facility | Minimum | LIBOR
Line of Credit Facility [Line Items]
Applicable margin		1.75%
Revolving credit facility | Maximum
Line of Credit Facility [Line Items]
Total leverage ratio		5.5
Commitment fee on unused portion of the facility		0.50%
Revolving credit facility | Maximum | ABR
Line of Credit Facility [Line Items]
Applicable margin		1.75%
Revolving credit facility | Maximum | LIBOR
Line of Credit Facility [Line Items]
Applicable margin		2.75%

DEBT - Senior Notes (Details)

DEBT - Senior Notes (Details) - USD ($)	1 Months Ended
	Jul. 31, 2014	Jun. 30, 2013	Feb. 27, 2017	Feb. 16, 2017	Feb. 14, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Notice of redemption						$ 1,248,000,000
Senior Notes
Debt Instrument [Line Items]
Debt defaults						0
5.5% Senior Notes | Senior Notes
Debt Instrument [Line Items]
Debt face amount						$ 300,000,000
Stated interest rate						5.50%
Debt issuance costs	$ 5,100,000
Events of default, period of payment default	30 days
Events of default, failure to comply with covenants, period after notice	180 days
Events of default, failure to comply with other agreements in the indenture, period after notice	30 days
Events of default, failure to pay final judgments, in excess of 20.0 million	$ 20,000,000
Declaration of immediate payment, holding percent of principal amount required	25.00%
7.5% Senior Notes | Senior Notes
Debt Instrument [Line Items]
Debt face amount						$ 300,000,000
Stated interest rate						7.50%
Summit Holdings and Finance Corporation | 5.5% Senior Notes | Senior Notes
Debt Instrument [Line Items]
Senior unsecured notes	$ 300,000,000
Stated interest rate	5.50%
Maximum percent of aggregate principal amount redeemable	35.00%
Summit Holdings and Finance Corporation | 7.5% Senior Notes | Senior Notes
Debt Instrument [Line Items]
Senior unsecured notes		$ 300,000,000
Stated interest rate		7.50%
Debt issuance costs		$ 7,400,000
Debt defaults						$ 0
Summit Holdings and Finance Corporation | Prior to August 15, 2017 | 5.5% Senior Notes | Senior Notes
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount	105.50%
Summit Holdings and Finance Corporation | On and after August 15, 2017 | 5.5% Senior Notes | Senior Notes
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount	104.125%
Summit Holdings and Finance Corporation | On and after August 15, 2020 | 5.5% Senior Notes | Senior Notes
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount	100.00%
Summit Holdings and Finance Corporation | July 1, 2016 - June 30, 2019 | 7.5% Senior Notes | Senior Notes
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount		105.625%
Summit Holdings and Finance Corporation | July 1, 2019 | 7.5% Senior Notes | Senior Notes
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount		100.00%
Finance Corp | Summit Holdings
Debt Instrument [Line Items]
Cumulative percentage ownership in subsidiary	100.00%
Subsequent Event | Senior Unsecured Notes Due April 2025 | Unsecured Debt
Debt Instrument [Line Items]
Debt face amount			$ 500,000,000
Stated interest rate			5.75%
Subsequent Event | Summit Holdings and Finance Corporation | 7.5% Senior Notes | Senior Notes
Debt Instrument [Line Items]
Amount validly tendered					$ 276,900,000
Notice of redemption				$ 23,100,000

DEBT - SMP Holdings Credit Faci

DEBT - SMP Holdings Credit Facility (Details) - USD ($)	1 Months Ended			12 Months Ended
	May 31, 2015	May 31, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Feb. 29, 2016	Jan. 31, 2016
Debt Instrument [Line Items]
Repayments under term loan				$ 0	$ 182,500,000	$ 100,000,000
Write-off of debt issuance costs				0	727,000	1,554,000
Borrowings under term loan				0	$ 0	$ 400,000,000
Revolving credit facility
Debt Instrument [Line Items]
Borrowing capacity				1,250,000,000			$ 1,250,000,000	$ 700,000,000
SMP Holdings | SMP Holdings Credit Facility
Debt Instrument [Line Items]
Write-off of debt issuance costs			$ 1,500,000
SMP Holdings | Senior Secured Term Loan | SMP Holdings Credit Facility
Debt Instrument [Line Items]
Debt face amount				200,000,000
Repayments under term loan			100,000,000
Write-off of debt issuance costs	$ 700,000
Borrowings under term loan		$ 400,000,000
SMP Holdings | Revolving credit facility | SMP Holdings Credit Facility
Debt Instrument [Line Items]
Borrowing capacity				$ 250,000,000
Repayments of lines of credit			$ 95,000,000

FINANCIAL INSTRUMENTS - Concent

FINANCIAL INSTRUMENTS - Concentration Risk (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Five Largest Customers | Accounts receivable | Customer concentration
CONCENTRATIONS OF RISK
Concentration risk, percentage	62.00%	68.00%

FINANCIAL INSTRUMENTS - Fair Va

FINANCIAL INSTRUMENTS - Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation (Details) - Fair Value, Inputs, Level 3 $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Level 3 liability, beginning of period	$ 0
Addition	507,427
Change in fair value	55,854
Drop Down Assets 2016 Acquisition
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Level 3 liability, end of period	$ 563,281

FINANCIAL INSTRUMENTS - Fair 70

FINANCIAL INSTRUMENTS - Fair value of Debt Instruments (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Revolving credit facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Line of Credit	$ 648,000,000	$ 344,000,000
SMP Holdings | Revolving credit facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Line of Credit	$ 0	115,000,000
Senior Notes | 5.5% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	5.50%
Debt face amount	$ 300,000,000
Senior Notes | 7.5% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	7.50%
Debt face amount	$ 300,000,000
Carrying value | Revolving credit facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revolving credit facility		344,000,000
Carrying value | SMP Holdings | Revolving credit facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revolving credit facility	0	115,000,000
Carrying value | Senior Notes | 5.5% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	296,484,000	295,861,000
Carrying value | Senior Notes | 7.5% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	295,817,000	294,909,000
Carrying value | Senior Notes | SMP Holdings | Senior Secured Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Term loan	0	217,500,000
Estimated fair value (Level 2) | Revolving credit facility | Estimated fair value (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revolving credit facility	648,000,000	344,000,000
Estimated fair value (Level 2) | SMP Holdings | Revolving credit facility | Estimated fair value (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revolving credit facility	0	115,000,000
Estimated fair value (Level 2) | Senior Notes | 5.5% Senior Notes | Estimated fair value (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	294,500,000	224,000,000
Estimated fair value (Level 2) | Senior Notes | 7.5% Senior Notes | Estimated fair value (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	316,000,000	257,000,000
Estimated fair value (Level 2) | Senior Notes | SMP Holdings | Senior Secured Term Loan | Estimated fair value (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Term loan	$ 0	$ 217,500,000

PARTNERS' CAPITAL - Partners' C

PARTNERS' CAPITAL - Partners' Capital and Schedule of Units (Details) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Rollforwards of the number of partner units
Units, beginning balance	67,827,194	60,037,014	54,581,169
Subordinated units conversion	0
Units issued in connection with offering	5,500,000	7,475,000	5,408,337
Contribution from General Partner	112,245	152,551	108,337
Net units issued under SMLP LTIP	142,869	162,629	47,508
Units, ending balance	73,582,308	67,827,194	60,037,014
Common
Rollforwards of the number of partner units
Units, beginning balance	42,062,644	34,426,513	29,079,866
Subordinated units conversion	24,409,850
Units issued in connection with offering	5,500,000	7,475,000	5,300,000
Contribution from General Partner	0	0	0
Net units issued under SMLP LTIP	138,627	161,131	46,647
Units, ending balance	72,111,121	42,062,644	34,426,513
Subordinated
Rollforwards of the number of partner units
Units, beginning balance	24,409,850	24,409,850	24,409,850
Subordinated units conversion	(24,409,850)
Units issued in connection with offering	0	0	0
Contribution from General Partner	0	0	0
Net units issued under SMLP LTIP	0	0	0
Units, ending balance	0	24,409,850	24,409,850
General Partner
Rollforwards of the number of partner units
Units, beginning balance	1,354,700	1,200,651	1,091,453
Subordinated units conversion	0
Units issued in connection with offering	0	0	0
Contribution from General Partner	112,245	152,551	108,337
Net units issued under SMLP LTIP	4,242	1,498	861
Units, ending balance	1,471,187	1,354,700	1,200,651

PARTNERS' CAPITAL - Unit Offeri

PARTNERS' CAPITAL - Unit Offerings (Details) - $ / shares	May 22, 2015	Jan. 31, 2017	Sep. 30, 2016	May 31, 2015	Sep. 30, 2014	Mar. 31, 2014	Dec. 31, 2016
Common | Public Offering
Class of Stock [Line Items]
Common units sold in public offering (in shares)				6,500,000		10,350,000
Common units sold in public offering, price per share (in dollars per share)				$ 30.75		$ 38.75
Common | Over-Allotment Option
Class of Stock [Line Items]
Common units sold in public offering (in shares)	975,000
Common units sold in public offering, price per share (in dollars per share)	$ 30.75
SMLP | Common | Public Offering
Class of Stock [Line Items]
Common units sold in public offering (in shares)						5,300,000
Summit Investments | Common
Class of Stock [Line Items]
Common units sold in public offering (in shares)					4,347,826
Summit Investments | Common | Public Offering
Class of Stock [Line Items]
Common units sold in public offering (in shares)						5,050,000
General Partner
Class of Stock [Line Items]
General partner interest			2.00%	2.00%		2.00%	2.00%
Common Units
Class of Stock [Line Items]
Common units sold in public offering (in shares)			5,500,000
Common units sold in public offering, price per share (in dollars per share)			$ 23.20
Subsequent Event | Common | Public Offering
Class of Stock [Line Items]
Common units sold in public offering (in shares)		4,000,000

PARTNERS' CAPITAL - Subordinati

PARTNERS' CAPITAL - Subordination (Details)	3 Months Ended
	Dec. 31, 2015
Subordinated units
Schedule of Partners' Capital [Line Items]
Common unit per subordinated unit upon conversion at end of subordination period (in shares)	1

PARTNERS' CAPITAL - 2016 Drop D

PARTNERS' CAPITAL - 2016 Drop Down (Details) - Drop Down Assets 2016 Acquisition - USD ($) $ in Thousands	Mar. 03, 2016	Jun. 30, 2016	Dec. 31, 2016
Subsidiary or Equity Method Investee [Line Items]
Initial payment	$ 360,000
Deferred purchase price obligation	507,427		$ 563,300
Net investment	1,114,855
Working capital adjustment	$ (569)	$ 600

PARTNERS' CAPITAL - Schedule of

PARTNERS' CAPITAL - Schedule of Capital Distribution and Allocation to Partners (Details) - USD ($) $ in Thousands	Mar. 03, 2016	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Subsidiary or Equity Method Investee [Line Items]
Excess of acquired carrying value over consideration paid and recognized			$ 247,997	$ 0	$ 0
Drop Down Assets 2016 Acquisition
Subsidiary or Equity Method Investee [Line Items]
Summit Investments' net investment in the 2016 Drop Down Assets	$ 771,929
SMP Holdings borrowings allocated to 2016 Drop Down Assets and retained by Summit Investments	342,926
Acquired carrying value of 2016 Drop Down Assets	1,114,855
Deferred Purchase Price Obligation	507,427		563,300
Borrowings under Revolving Credit Facility	360,000
Working capital adjustment received from a subsidiary of Summit Investments	(569)	$ 600
Total consideration paid and recognized by SMLP	866,858
Excess of acquired carrying value over consideration paid and recognized	247,997
General Partner
Subsidiary or Equity Method Investee [Line Items]
Excess of acquired carrying value over consideration paid and recognized	4,953		4,953	2,607
Common
Subsidiary or Equity Method Investee [Line Items]
Excess of acquired carrying value over consideration paid and recognized	243,044		243,044	80,079
Summit Investments' equity in contributed subsidiaries
Subsidiary or Equity Method Investee [Line Items]
Excess of acquired carrying value over consideration paid and recognized	$ 247,997		$ (247,997)	$ (130,367)

PARTNERS' CAPITAL - Polar and D

PARTNERS' CAPITAL - Polar and Divide and Red Rock Drop Down (Details) - USD ($) $ in Thousands	May 18, 2015	Mar. 18, 2014	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Net investment			$ 0	$ 0
Red Rock Gathering Company, LLC
Business Acquisition [Line Items]
Percent of membership interest acquired		100.00%
Purchase price		$ 307,941
Polar Midstream and Epping
Business Acquisition [Line Items]
Percent of membership interest acquired	100.00%
Purchase price	$ 285,677
Summit Investments | Red Rock Gathering Company, LLC
Business Acquisition [Line Items]
Net investment		$ 241,817
Summit Investments | Polar Midstream and Epping
Business Acquisition [Line Items]
Net investment	$ 416,044

PARTNERS' CAPITAL - Schedule 77

PARTNERS' CAPITAL - Schedule of Polar and Divide and Red Rock (Details) - USD ($) $ in Thousands	May 18, 2015	Mar. 18, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investment [Line Items]
Net investment			$ 0	$ 0
Partners' capital contribution			2,702	4,737	$ 4,235
Partners' capital distribution			(167,504)	(152,074)	(122,224)
Summit Investments | Red Rock Gathering Company, LLC
Investment [Line Items]
Net investment		$ 241,817
Summit Investments | Polar Midstream and Epping
Investment [Line Items]
Net investment	$ 416,044
Red Rock Gathering Company, LLC
Investment [Line Items]
Purchase price		307,941
Partners' capital distribution		(66,124)
Polar Midstream and Epping
Investment [Line Items]
Purchase price	285,677
Partners' capital contribution	130,367
General Partner
Investment [Line Items]
Partners' capital contribution			2,702	4,737	4,235
Partners' capital distribution			(11,256)	(9,784)	(4,770)
General Partner | Red Rock Gathering Company, LLC
Investment [Line Items]
Partners' capital distribution		(1,323)
General Partner | Polar Midstream and Epping
Investment [Line Items]
Partners' capital contribution	2,607
Limited partners, Common
Investment [Line Items]
Partners' capital distribution			(142,214)	(86,880)	(67,658)
Limited partners, Common | Red Rock Gathering Company, LLC
Investment [Line Items]
Partners' capital distribution		(37,910)
Limited partners, Common | Polar Midstream and Epping
Investment [Line Items]
Partners' capital contribution	80,079
Subordinated
Investment [Line Items]
Partners' capital distribution			$ (14,034)	$ (55,410)	$ (49,796)
Subordinated | Red Rock Gathering Company, LLC
Investment [Line Items]
Partners' capital distribution		$ (26,891)
Subordinated | Polar Midstream and Epping
Investment [Line Items]
Partners' capital contribution	$ 47,681

PARTNERS' CAPITAL - Cash Distri

PARTNERS' CAPITAL - Cash Distribution Policy, General Partner Interest and Minimum Quarterly Distribution (Details)	12 Months Ended
	Dec. 31, 2016$ / shares
Entity Information [Line Items]
Maximum period following end of quarter to distribute all available cash	45 days
Minimum quarterly distributions (in dollars per share)	$ 0.40
Minimum annual distributions (in dollars per share)	$ 1.60
General Partner
Entity Information [Line Items]
Percentage interest in distributions	2.00%

PARTNERS' CAPITAL - Cash Dist79

PARTNERS' CAPITAL - Cash Distributions Paid and Declared (Details) - USD ($) $ / shares in Units, $ in Thousands	Feb. 14, 2017	Jan. 26, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Distribution Made to Limited Partner [Line Items]
Per-unit annual distributions to unitholders (in dollars per unit)			$ 2.3	$ 2.27	$ 2.04
Cash paid to unit holders			$ 167,504	$ 152,074	$ 122,224
Subsequent Event
Distribution Made to Limited Partner [Line Items]
Per-unit annual distributions to unitholders (in dollars per unit)		$ 0.575
Cash paid to unit holders	$ 44,500

PARTNERS' CAPITAL - Incentive D

PARTNERS' CAPITAL - Incentive Distribution Rights (Details)	12 Months Ended
	Dec. 31, 2016
General Partner
Entity Information [Line Items]
Percentage interest in distributions	2.00%

PARTNERS' CAPITAL - Percentage

PARTNERS' CAPITAL - Percentage Allocations of Available Cash (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Partnership Target Distributions [Line Items]
IDR payments	$ 7,912	$ 6,743	$ 2,326
Minimum quarterly distribution
Schedule of Partnership Target Distributions [Line Items]
Total quarterly distribution per unit target amount	$ 0.4
Thereafter
Schedule of Partnership Target Distributions [Line Items]
Total quarterly distribution per unit target amount	0.60
Minimum | First target distribution
Schedule of Partnership Target Distributions [Line Items]
Total quarterly distribution per unit target amount	0.40
Minimum | Second target distribution
Schedule of Partnership Target Distributions [Line Items]
Total quarterly distribution per unit target amount	0.46
Minimum | Third target distribution
Schedule of Partnership Target Distributions [Line Items]
Total quarterly distribution per unit target amount	0.50
Maximum | First target distribution
Schedule of Partnership Target Distributions [Line Items]
Total quarterly distribution per unit target amount	0.46
Maximum | Second target distribution
Schedule of Partnership Target Distributions [Line Items]
Total quarterly distribution per unit target amount	0.5
Maximum | Third target distribution
Schedule of Partnership Target Distributions [Line Items]
Total quarterly distribution per unit target amount	$ 0.6
Unitholders | Minimum quarterly distribution
Schedule of Partnership Target Distributions [Line Items]
Percentage interest in distributions	98.00%
Unitholders | First target distribution
Schedule of Partnership Target Distributions [Line Items]
Percentage interest in distributions	98.00%
Unitholders | Second target distribution
Schedule of Partnership Target Distributions [Line Items]
Percentage interest in distributions	85.00%
Unitholders | Third target distribution
Schedule of Partnership Target Distributions [Line Items]
Percentage interest in distributions	75.00%
Unitholders | Thereafter
Schedule of Partnership Target Distributions [Line Items]
Percentage interest in distributions	50.00%
General Partner
Schedule of Partnership Target Distributions [Line Items]
Percentage interest in distributions	2.00%
General Partner | Minimum quarterly distribution
Schedule of Partnership Target Distributions [Line Items]
Percentage interest in distributions	2.00%
General Partner | First target distribution
Schedule of Partnership Target Distributions [Line Items]
Percentage interest in distributions	2.00%
General Partner | Second target distribution
Schedule of Partnership Target Distributions [Line Items]
Percentage interest in distributions	15.00%
General Partner | Third target distribution
Schedule of Partnership Target Distributions [Line Items]
Percentage interest in distributions	25.00%
General Partner | Thereafter
Schedule of Partnership Target Distributions [Line Items]
Percentage interest in distributions	50.00%

EARNINGS PER UNIT (Details)

EARNINGS PER UNIT (Details) - USD ($) $ / shares in Units, $ in Thousands	Feb. 16, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Allocation of net loss among limited partner interests		$ 11,522	$ (215)	$ (51,222)	$ (8,264)	$ (217,999)	$ 21,196	$ 1,094	$ 99	$ (48,179)	$ (195,610)	$ (27,117)
Phantom Units
Loss per limited partner unit:
Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU (in shares)										125,000	109,000	232,000
Common units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Allocation of net loss among limited partner interests										$ (48,179)	$ (125,437)	$ (16,324)
Weighted-average units outstanding (in shares)										68,264,000	39,217,000	33,311,000
Effect of nonvested phantom units (in shares)										0	0	0
Weighted-average units outstanding – diluted (shares)										68,264,000	39,217,000	33,311,000
Loss per limited partner unit:
Basic (in dollars per share)		$ 0.16	$ 0	$ (0.77)	$ (0.12)	$ (3.28)	$ 0.32	$ 0.05	$ 0	$ (0.71)	$ (3.20)	$ (0.49)
Diluted (in dollars per share)		$ 0.16	$ 0	$ (0.77)	$ (0.12)	(3.28)	0.32	0.05	0	$ (0.71)	$ (3.20)	$ (0.49)
Subordinated Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Allocation of net loss among limited partner interests											$ (70,173)	$ (10,793)
Weighted-average units outstanding (in shares)											24,410,000	24,410,000
Weighted-average units outstanding – diluted (shares)											24,410,000	24,410,000
Loss per limited partner unit:
Basic (in dollars per share)						$ (3.28)	$ 0.32	$ (0.03)	$ 0		$ (2.88)	$ (0.44)
Diluted (in dollars per share)											$ (2.88)	$ (0.44)
Number of units converted (in shares)	24,409,850

UNIT-BASED AND NONCASH COMPEN83

UNIT-BASED AND NONCASH COMPENSATION - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2013
Phantom Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years
SMLP LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserved for issuance (in shares)	5,000,000
Units remaining available	3,900,000
Unrecognized unit-based compensation	$ 5.4
Remaining vesting period	2 years 2 months
Forfeitures	0

UNIT-BASED AND NONCASH COMPEN84

UNIT-BASED AND NONCASH COMPENSATION - SMLP Long-Term Incentive Plan (Details) - SMLP LTIP - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Phantom and Restricted Units
Phantom and Restricted Unit Activity
Nonvested units, beginning of period (in shares)			283,682
Unit vested (in shares)			(61,917)
Weighted-average grant date fair value
Nonvested, Weighted-average grant date fair value, beginning (in dollars per unit)			$ 23.41
Units vested, Weighted-average grant date fair value (in dollars per unit)			$ 25.33
Phantom Units
Phantom and Restricted Unit Activity
Nonvested units, beginning of period (in shares)	379,911	336,202
Units granted (in shares)	495,535	289,735	136,867
Unit vested (in shares)	(178,953)	(229,497)
Units forfeited (in shares)	(4,538)	(16,529)	(22,430)
Nonvested units, end of period (in shares)	691,955	379,911	336,202
Weighted-average grant date fair value
Nonvested, Weighted-average grant date fair value, beginning (in dollars per unit)	$ 31.13	$ 30.61
Units granted, Weighted-average grant date fair value (in dollars per unit)	14.91	29.21	$ 42.32
Units vested, Weighted-average grant date fair value (in dollars per unit)	33.80	27.66
Units forfeited, Weighted-average grant date fair value (in dollars per unit)	16.89	35.09	25.56
Nonvested, Weighted-average grant date fair value, ending (in dollars per unit)	$ 19.59	$ 31.13	$ 30.61

UNIT-BASED AND NONCASH COMPEN85

UNIT-BASED AND NONCASH COMPENSATION - Schedule of Intrinsic Values (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
SMLP LTIP | Phantom and Restricted Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of vested LTIP awards	$ 2,957	$ 5,362	$ 2,631

UNIT-BASED AND NONCASH COMPEN86

UNIT-BASED AND NONCASH COMPENSATION - SMP Net Profits Interests (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
SMLP LTIP unit-based compensation	$ 7,550	$ 6,174	$ 4,696
SMLP LTIP | General and administrative expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
SMLP LTIP unit-based compensation	$ 7,550	$ 6,174	$ 4,696

RELATED-PARTY TRANSACTIONS (Det

RELATED-PARTY TRANSACTIONS (Details) - General Partner - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operation and maintenance expense
RELATED-PARTY TRANSACTIONS
Expenses from transactions with related party	$ 26,485	$ 25,050	$ 22,004
General and administrative expense
RELATED-PARTY TRANSACTIONS
Expenses from transactions with related party	$ 31,947	$ 26,193	$ 24,993

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Rent Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 2,861	$ 2,395	$ 1,881

COMMITMENTS AND CONTINGENCIES89

COMMITMENTS AND CONTINGENCIES - Schedule of Future Minimum Rental Payments for Operating Leases (Details) $ in Thousands	Dec. 31, 2016USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,017	$ 3,512
2,018	3,178
2,019	2,520
2,020	442
2,021	34
Thereafter	0
Total future minimum lease payments	$ 9,686

COMMITMENTS AND CONTINGENCIES90

COMMITMENTS AND CONTINGENCIES - Environmental Matters (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Meadowland Midstream Gathering System
Accrual for Environmental Loss Contingencies [Roll Forward]
Accrued environmental remediation, beginning balance		$ 9,453,000	$ 13,664,000	$ 30,000,000
Payments made by affiliates				(13,136,000)
Payments made with proceeds from insurance policies				(25,000,000)
Additional accruals				21,800,000
Payments made, including those by affiliates			(4,211,000)
Accrued environmental remediation, ending balance			9,453,000	13,664,000
Meadowland Midstream Gathering System | Principal Owner | North Dakota Industrial Commission Case
Accrual for Environmental Loss Contingencies [Roll Forward]
Fines and other fees sought	$ 2,500,000
Maximum | Meadowland Midstream Gathering System | Principal Owner
Loss Contingencies [Line Items]
Coverage from pollution liability insurance policy			25,000,000	$ 25,000,000
Coverage from property and business interruption insurance policy			$ 200,000,000
Forecast | Business Interruption
Loss Contingencies [Line Items]
Recoveries recognized		2,600,000
Forecast | Property Recoveries
Loss Contingencies [Line Items]
Recoveries recognized		$ 400,000

ACQUISITIONS AND DROP DOWN TR91

ACQUISITIONS AND DROP DOWN TRANSACTIONS - 2016 Drop Down (Details) - Drop Down Assets 2016 Acquisition $ in Thousands	Mar. 03, 2016USD ($)	Jun. 30, 2016USD ($)	Dec. 31, 2016USD ($)
Business Acquisition [Line Items]
Initial payment	$ 360,000
Working capital adjustment	$ (569)	$ 600
Deferred Purchase price obligation, multiple	6.5
Estimated future payment obligation	$ 860,300		$ 830,300
Deferred purchase price obligation	$ 507,427		$ 563,300
Discount rate	13.00%		12.00%

ACQUISITIONS AND DROP DOWN TR92

ACQUISITIONS AND DROP DOWN TRANSACTIONS - Summit Utica (Details) $ in Millions	Dec. 15, 2014USD ($)
Principal Owner | Utica Shale Play
Business Acquisition [Line Items]
Purchase price	$ 25.2

ACQUISITIONS AND DROP DOWN TR93

ACQUISITIONS AND DROP DOWN TRANSACTIONS - Meadowlark Midstream (Details) - Principal Owner - Meadowlark Midstream Company, LLC $ in Thousands	Feb. 15, 2013USD ($)
Business Acquisition [Line Items]
Purchase price	$ 25,376
Current assets	2,227
Property, plant and equipment	18,795
Other noncurrent assets	4,354
Total assets acquired	25,376
Total liabilities assumed	0
Net identifiable assets acquired	$ 25,376

ACQUISITIONS AND DROP DOWN TR94

ACQUISITIONS AND DROP DOWN TRANSACTIONS - Polar and Divide Drop Down (Details) - USD ($) $ in Thousands	May 18, 2015	Feb. 15, 2013	Jul. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Values of Assets Acquired and Liabilities Assumed:
Goodwill				$ 16,211	$ 16,211	$ 265,062
Polar Midstream and Epping
Business Acquisition [Line Items]
Total consideration	$ 285,677
Liabilities incurred for acquisition	92,000
Cash payment for working capital and capital expenditure adjustments			$ 4,300
Fair Values of Assets Acquired and Liabilities Assumed:
Purchase price	285,677
Polar Midstream and Epping | Common units
Business Acquisition [Line Items]
Issuance of stock	193,400
Polar Midstream and Epping | General Partner Units
Business Acquisition [Line Items]
Issuance of stock	4,100
Polar Midstream and Epping | Previously Reported
Business Acquisition [Line Items]
Total consideration	290,000
Fair Values of Assets Acquired and Liabilities Assumed:
Purchase price	$ 290,000
Polar Midstream | Summit Investments
Business Acquisition [Line Items]
Total consideration		$ 216,105
Fair Values of Assets Acquired and Liabilities Assumed:
Purchase price		216,105
Current assets		368
Property, plant and equipment		9,755
Other noncurrent assets		7,201
Total assets acquired		17,324
Current liabilities		4,592
Total liabilities assumed		4,592
Net identifiable assets acquired		12,732
Goodwill		$ 203,373

ACQUISITIONS AND DROP DOWN TR95

ACQUISITIONS AND DROP DOWN TRANSACTIONS - Red Rock Gathering (Details) - USD ($) $ in Thousands	Mar. 18, 2014	Feb. 28, 2015	Mar. 31, 2014	Feb. 28, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Purchase accounting adjustments					$ 0	$ 0	$ 1,185
Red Rock Gathering Company, LLC
Business Acquisition [Line Items]
Cost of acquired entity, cash paid	$ 305,000	$ 2,900		$ 307,900
Purchase accounting adjustments							$ 1,200
Red Rock Gathering Company, LLC | Revolving credit facility
Business Acquisition [Line Items]
Borrowings incurred for acquisition			$ 100,000

ACQUISITIONS AND DROP DOWN TR96

ACQUISITIONS AND DROP DOWN TRANSACTIONS - Lonestar Assets (Details) - Barnett Shale Play $ in Millions	Sep. 30, 2014USD ($)contract
Property, Plant and Equipment [Line Items]
Payments to acquire gas gathering assets | $	$ 10.9
Number of long-term, fee-based contracts | contract	2

ACQUISITIONS AND DROP DOWN TR97

ACQUISITIONS AND DROP DOWN TRANSACTIONS - Revenue and Net Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Combined revenues	$ 127,083	$ 95,073	$ 89,635	$ 90,571	$ 112,414	$ 115,201	$ 86,855	$ 86,087	$ 402,362	$ 400,557	$ 387,169
Combined net loss									(38,187)	(222,228)	(47,368)
Summit Midstream Partners, LP
Business Acquisition [Line Items]
Combined revenues									393,495	358,046	338,941
Combined net loss									(40,932)	(192,212)	(23,992)
Drop Down Assets 2016 Acquisition
Business Acquisition [Line Items]
Combined revenues									8,867	29,238	14,466
Combined net loss									2,745	(35,419)	(32,634)
Polar Midstream and Epping
Business Acquisition [Line Items]
Combined revenues									0	13,273	22,449
Combined net loss									0	5,403	6,430
Red Rock Gathering Company, LLC
Business Acquisition [Line Items]
Combined revenues									0	0	11,313
Combined net loss									$ 0	$ 0	$ 2,828

CONDENSED CONSOLIDATING FINAN98

CONDENSED CONSOLIDATING FINANCIAL INFORMATION - Condensed Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Cash and cash equivalents	$ 7,428	$ 21,793	$ 27,811	$ 25,784
Accounts receivable	97,364	89,581
Other current assets	4,309	3,573
Due from affiliate	0	0
Total current assets	109,101	114,947
Property, plant and equipment, net	1,853,671	1,812,783
Intangible assets, net	421,452	461,310
Goodwill	16,211	16,211	265,062
Investment in equity method investees	707,415	751,168
Other noncurrent assets	7,329	8,253
Investment in subsidiaries	0	0
Total assets	3,115,179	3,164,672	3,242,462
Liabilities [Abstract]
Trade accounts payable	16,251	40,808
Accrued expenses	11,389	6,776
Due to affiliate	258	1,149
Deferred revenue	0	677	2,377
Ad valorem taxes payable	10,588	10,271
Accrued interest	17,483	17,483
Accrued environmental remediation	4,301	7,900
Other current liabilities	11,471	6,521
Total current liabilities	71,741	91,585
Long-term debt	1,240,301	1,267,270
Deferred Purchase Price Obligation	563,281	0
Deferred revenue	57,465	45,486	55,239
Noncurrent accrued environmental remediation	5,152	5,764
Other noncurrent liabilities	7,566	7,268
Total liabilities	1,945,506	1,417,373
Total partners' capital	1,169,673	1,747,299	1,830,678	1,395,806
Total liabilities and partners' capital	3,115,179	3,164,672
Consolidating adjustments
Assets
Cash and cash equivalents	0	0	0	0
Accounts receivable	0	0
Other current assets	0	0
Due from affiliate	(422,904)	(362,262)
Total current assets	(422,904)	(362,262)
Property, plant and equipment, net	0	0
Intangible assets, net	0	0
Goodwill	0	0
Investment in equity method investees	0	0
Other noncurrent assets	0	0
Investment in subsidiaries	(5,480,150)	(5,660,582)
Total assets	(5,903,054)	(6,022,844)
Liabilities [Abstract]
Trade accounts payable	0	0
Accrued expenses	0	0
Due to affiliate	(422,904)	(362,262)
Deferred revenue		0
Ad valorem taxes payable	0	0
Accrued interest	0	0
Accrued environmental remediation	0	0
Other current liabilities	0	0
Total current liabilities	(422,904)	(362,262)
Long-term debt	0	0
Deferred Purchase Price Obligation	0
Deferred revenue	0	0
Noncurrent accrued environmental remediation	0	0
Other noncurrent liabilities	0	0
Total liabilities	(422,904)	(362,262)
Total partners' capital	(5,480,150)	(5,660,582)
Total liabilities and partners' capital	(5,903,054)	(6,022,844)
SMLP | Reportable Legal Entities
Assets
Cash and cash equivalents	698	73	7,531	6,291
Accounts receivable	53	0
Other current assets	1,526	540
Due from affiliate	14,896	3,168
Total current assets	17,173	3,781
Property, plant and equipment, net	2,266	1,178
Intangible assets, net	0	0
Goodwill	0	0
Investment in equity method investees	0	0
Other noncurrent assets	1,993	3,480
Investment in subsidiaries	2,132,757	2,438,395
Total assets	2,154,189	2,446,834
Liabilities [Abstract]
Trade accounts payable	978	482
Accrued expenses	2,399	1,478
Due to affiliate	408,266	360,243
Deferred revenue		0
Ad valorem taxes payable	16	9
Accrued interest	0	0
Accrued environmental remediation	0	0
Other current liabilities	6,718	3,080
Total current liabilities	418,377	365,292
Long-term debt	0	332,500
Deferred Purchase Price Obligation	563,281
Deferred revenue	0	0
Noncurrent accrued environmental remediation	0	0
Other noncurrent liabilities	2,858	1,743
Total liabilities	984,516	699,535
Total partners' capital	1,169,673	1,747,299
Total liabilities and partners' capital	2,154,189	2,446,834
Co-Issuers | Reportable Legal Entities
Assets
Cash and cash equivalents	51	12,407	11,621	125
Accounts receivable	0	0
Other current assets	0	0
Due from affiliate	38,013	151,443
Total current assets	38,064	163,850
Property, plant and equipment, net	0	0
Intangible assets, net	0	0
Goodwill	0	0
Investment in equity method investees	0	0
Other noncurrent assets	5,198	4,611
Investment in subsidiaries	3,347,393	3,222,187
Total assets	3,390,655	3,390,648
Liabilities [Abstract]
Trade accounts payable	0	0
Accrued expenses	114	0
Due to affiliate	0	0
Deferred revenue		0
Ad valorem taxes payable	0	0
Accrued interest	17,483	17,483
Accrued environmental remediation	0	0
Other current liabilities	0	0
Total current liabilities	17,597	17,483
Long-term debt	1,240,301	934,770
Deferred Purchase Price Obligation	0
Deferred revenue	0	0
Noncurrent accrued environmental remediation	0	0
Other noncurrent liabilities	0	0
Total liabilities	1,257,898	952,253
Total partners' capital	2,132,757	2,438,395
Total liabilities and partners' capital	3,390,655	3,390,648
Guarantor Subsidiaries | Reportable Legal Entities
Assets
Cash and cash equivalents	5,647	6,930	7,353	13,942
Accounts receivable	89,584	84,021
Other current assets	2,328	2,672
Due from affiliate	369,995	207,651
Total current assets	467,554	301,274
Property, plant and equipment, net	1,440,180	1,462,623
Intangible assets, net	396,930	438,093
Goodwill	16,211	16,211
Investment in equity method investees	0	0
Other noncurrent assets	138	162
Investment in subsidiaries	0	0
Total assets	2,321,013	2,218,363
Liabilities [Abstract]
Trade accounts payable	9,901	18,489
Accrued expenses	6,069	4,832
Due to affiliate	0	0
Deferred revenue		677
Ad valorem taxes payable	9,717	9,881
Accrued interest	0	0
Accrued environmental remediation	0	0
Other current liabilities	3,798	2,573
Total current liabilities	29,485	36,452
Long-term debt	0	0
Deferred Purchase Price Obligation	0
Deferred revenue	57,465	45,486
Noncurrent accrued environmental remediation	0	0
Other noncurrent liabilities	4,602	5,503
Total liabilities	91,552	87,441
Total partners' capital	2,229,461	2,130,922
Total liabilities and partners' capital	2,321,013	2,218,363
Non-Guarantor Subsidiaries | Reportable Legal Entities
Assets
Cash and cash equivalents	1,032	2,383	$ 1,306	$ 5,426
Accounts receivable	7,727	5,560
Other current assets	455	361
Due from affiliate	0	0
Total current assets	9,214	8,304
Property, plant and equipment, net	411,225	348,982
Intangible assets, net	24,522	23,217
Goodwill	0	0
Investment in equity method investees	707,415	751,168
Other noncurrent assets	0	0
Investment in subsidiaries	0	0
Total assets	1,152,376	1,131,671
Liabilities [Abstract]
Trade accounts payable	5,372	21,837
Accrued expenses	2,807	466
Due to affiliate	14,896	3,168
Deferred revenue		0
Ad valorem taxes payable	855	381
Accrued interest	0	0
Accrued environmental remediation	4,301	7,900
Other current liabilities	955	868
Total current liabilities	29,186	34,620
Long-term debt	0	0
Deferred Purchase Price Obligation	0
Deferred revenue	0	0
Noncurrent accrued environmental remediation	5,152	5,764
Other noncurrent liabilities	106	22
Total liabilities	34,444	40,406
Total partners' capital	1,117,932	1,091,265
Total liabilities and partners' capital	$ 1,152,376	$ 1,131,671

CONDENSED CONSOLIDATING FINAN99

CONDENSED CONSOLIDATING FINANCIAL INFORMATION - Condensed Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Gathering services and related fees									$ 345,961	$ 337,819	$ 267,478
Natural gas, NGLs and condensate sales									35,833	42,079	97,094
Other revenues									20,568	20,659	22,597
Total revenues	$ 127,083	$ 95,073	$ 89,635	$ 90,571	$ 112,414	$ 115,201	$ 86,855	$ 86,087	402,362	400,557	387,169
Costs and expenses:
Cost of natural gas and NGLs									27,421	31,398	72,415
Operation and maintenance									95,334	94,986	94,869
General and administrative									52,410	45,108	43,281
Depreciation and amortization									112,239	105,117	90,878
Transaction costs									1,321	1,342	2,985
Environmental remediation						20,000			0	21,800	5,000
Loss (gain) on asset sales, net									93	(172)	442
Long-lived asset impairment					1,600	$ 7,700			1,764	9,305	5,505
Goodwill impairment					$ 248,900				0	248,851	54,199
Total costs and expenses									290,582	557,735	369,574
Other income									116	2	1,189
Interest expense									(63,810)	(59,092)	(48,586)
Deferred Purchase Price Obligation expense									(55,854)	0	0
Loss before income taxes and loss from equity method investees									(7,768)	(216,268)	(29,802)
Income tax expense									(75)	603	(854)
Loss from equity method investees									(30,344)	(6,563)	(16,712)
Equity in earnings of consolidated subsidiaries									0	0	0
Net loss									(38,187)	(222,228)	(47,368)
Consolidating adjustments
Revenues:
Gathering services and related fees									0	0	0
Natural gas, NGLs and condensate sales									0	0	0
Other revenues									0	0	0
Total revenues									0	0	0
Costs and expenses:
Cost of natural gas and NGLs									0	0	0
Operation and maintenance									0	0	0
General and administrative									0	0	0
Depreciation and amortization									0	0	0
Transaction costs									0	0	0
Environmental remediation										0	0
Loss (gain) on asset sales, net									0	0	0
Long-lived asset impairment									0	0	0
Goodwill impairment										0	0
Total costs and expenses									0	0	0
Other income									0	0	0
Interest expense									0	0	0
Deferred Purchase Price Obligation expense									0
Loss before income taxes and loss from equity method investees									0	0	0
Income tax expense									0	0	0
Loss from equity method investees									0	0	0
Equity in earnings of consolidated subsidiaries									(104,305)	372,190	27,227
Net loss									(104,305)	372,190	27,227
Co-Issuers | Reportable Legal Entities
Revenues:
Gathering services and related fees									0	0	0
Natural gas, NGLs and condensate sales									0	0	0
Other revenues									0	0	0
Total revenues									0	0	0
Costs and expenses:
Cost of natural gas and NGLs									0	0	0
Operation and maintenance									0	0	0
General and administrative									0	0	0
Depreciation and amortization									0	0	0
Transaction costs									0	0	0
Environmental remediation										0	0
Loss (gain) on asset sales, net									0	0	0
Long-lived asset impairment									0	0	0
Goodwill impairment										0	0
Total costs and expenses									0	0	0
Other income									0	0	0
Interest expense									(62,369)	(48,598)	(40,169)
Deferred Purchase Price Obligation expense									0
Loss before income taxes and loss from equity method investees									(62,369)	(48,598)	(40,169)
Income tax expense									0	0	0
Loss from equity method investees									0	0	0
Equity in earnings of consolidated subsidiaries									83,337	(161,796)	6,471
Net loss									20,968	(210,394)	(33,698)
Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Gathering services and related fees									288,399	310,830	255,211
Natural gas, NGLs and condensate sales									35,833	42,079	97,094
Other revenues									18,225	18,411	20,398
Total revenues									342,457	371,320	372,703
Costs and expenses:
Cost of natural gas and NGLs									27,421	31,398	72,415
Operation and maintenance									84,632	87,286	88,927
General and administrative									43,612	37,926	40,447
Depreciation and amortization									98,891	95,586	86,762
Transaction costs									0	0	0
Environmental remediation										0	0
Loss (gain) on asset sales, net									99	(172)	442
Long-lived asset impairment									1,235	9,305	5,505
Goodwill impairment										248,851	54,199
Total costs and expenses									255,890	510,180	348,697
Other income									0	0	1,189
Interest expense									0	0	0
Deferred Purchase Price Obligation expense									0
Loss before income taxes and loss from equity method investees									86,567	(138,860)	25,195
Income tax expense									0	0	826
Loss from equity method investees									0	0	0
Equity in earnings of consolidated subsidiaries									0	0	0
Net loss									86,567	(138,860)	26,021
Non-Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Gathering services and related fees									57,562	26,989	12,267
Natural gas, NGLs and condensate sales									0	0	0
Other revenues									2,343	2,248	2,199
Total revenues									59,905	29,237	14,466
Costs and expenses:
Cost of natural gas and NGLs									0	0	0
Operation and maintenance									10,702	7,700	5,942
General and administrative									8,798	7,182	2,834
Depreciation and amortization									12,768	8,928	3,528
Transaction costs									0	0	0
Environmental remediation										21,800	5,000
Loss (gain) on asset sales, net									(6)	0	0
Long-lived asset impairment									529	0	0
Goodwill impairment										0	0
Total costs and expenses									32,791	45,610	17,304
Other income									0	0	0
Interest expense									0	0	0
Deferred Purchase Price Obligation expense									0
Loss before income taxes and loss from equity method investees									27,114	(16,373)	(2,838)
Income tax expense									0	0	0
Loss from equity method investees									(30,344)	(6,563)	(16,712)
Equity in earnings of consolidated subsidiaries									0	0	0
Net loss									(3,230)	(22,936)	(19,550)
SMLP | Reportable Legal Entities
Revenues:
Gathering services and related fees									0	0	0
Natural gas, NGLs and condensate sales									0	0	0
Other revenues									0	0	0
Total revenues									0	0	0
Costs and expenses:
Cost of natural gas and NGLs									0	0	0
Operation and maintenance									0	0	0
General and administrative									0	0	0
Depreciation and amortization									580	603	588
Transaction costs									1,321	1,342	2,985
Environmental remediation										0	0
Loss (gain) on asset sales, net									0	0	0
Long-lived asset impairment									0	0	0
Goodwill impairment										0	0
Total costs and expenses									1,901	1,945	3,573
Other income									116	2	0
Interest expense									(1,441)	(10,494)	(8,417)
Deferred Purchase Price Obligation expense									(55,854)
Loss before income taxes and loss from equity method investees									(59,080)	(12,437)	(11,990)
Income tax expense									(75)	603	(1,680)
Loss from equity method investees									0	0	0
Equity in earnings of consolidated subsidiaries									20,968	(210,394)	(33,698)
Net loss									$ (38,187)	$ (222,228)	$ (47,368)

CONDENSED CONSOLIDATING FINA100

CONDENSED CONSOLIDATING FINANCIAL INFORMATION - Condensed Cash Flow Statement (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 230,495	$ 191,375	$ 152,953
Cash flows from investing activities:
Capital expenditures	(142,719)	(272,225)	(343,380)
Contributions to equity method investees	(31,582)	(86,200)	(145,131)
Acquisition of gathering systems	0	0	(10,872)
Acquisitions of gathering systems from affiliate, net of acquired cash	(359,431)	(288,618)	(305,000)
Other, net	(394)	323	325
Advances to affiliates	0	0	0
Initial contribution to Ohio Gathering	0	0	(8,360)
Acquisition of Ohio Gathering Option	0	0	(190,000)
Option Exercise	0	0	(382,385)
Net cash used in investing activities	(534,126)	(646,720)	(1,384,803)
Cash flows from financing activities:
Distributions to unitholders	(167,504)	(152,074)	(122,224)
Borrowings under Revolving Credit Facility	520,300	367,000	294,295
Repayments under Revolving Credit Facility	(204,300)	(151,000)	(430,295)
Repayments under term loan	0	(182,500)	(100,000)
Borrowings under term loan	0	0	400,000
Debt issuance costs	(3,032)	(412)	(8,323)
Proceeds from issuance of common units, net	125,233	221,977	197,806
Contribution from General Partner	2,702	4,737	4,235
Cash advance (to) from Summit Investments (from) to contributed subsidiaries, net	12,214	320,527	674,383
Expenses paid by Summit Investments on behalf of contributed subsidiaries	4,821	22,879	24,884
Issuance of senior notes	0	0	300,000
Repurchase of equity-based compensation awards	0	0	(228)
Other, net	(1,168)	(1,807)	(656)
Advances from affiliates	0	0	0
Net cash provided by financing activities	289,266	449,327	1,233,877
Net change in cash and cash equivalents	(14,365)	(6,018)	2,027
Cash and cash equivalents, beginning of period	21,793	27,811	25,784
Cash and cash equivalents, end of period	7,428	21,793	27,811
Cash and Cash Equivalents, Period Increase (Decrease)	(14,365)
Consolidating adjustments
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	0	0	0
Cash flows from investing activities:
Capital expenditures	0	0	0
Contributions to equity method investees	0	0	0
Acquisition of gathering systems			0
Acquisitions of gathering systems from affiliate, net of acquired cash	0	0	0
Other, net	0	0	0
Advances to affiliates	421,542	200,813	221,949
Initial contribution to Ohio Gathering			0
Acquisition of Ohio Gathering Option			0
Option Exercise			0
Net cash used in investing activities	421,542	200,813	221,949
Cash flows from financing activities:
Distributions to unitholders	0	0	0
Borrowings under Revolving Credit Facility	0	0	0
Repayments under Revolving Credit Facility	0	0	0
Repayments under term loan		0	0
Borrowings under term loan			0
Debt issuance costs	0	0	0
Proceeds from issuance of common units, net	0	0	0
Contribution from General Partner	0	0	0
Cash advance (to) from Summit Investments (from) to contributed subsidiaries, net	0	0	0
Expenses paid by Summit Investments on behalf of contributed subsidiaries	0	0	0
Issuance of senior notes			0
Repurchase of equity-based compensation awards			0
Other, net	0	0	0
Advances from affiliates	(421,542)	(200,813)	(221,949)
Net cash provided by financing activities	(421,542)	(200,813)	(221,949)
Net change in cash and cash equivalents		0	0
Cash and cash equivalents, beginning of period	0	0	0
Cash and cash equivalents, end of period	0	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	0
SMLP | Reportable Legal Entities
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	9,691	409	(3,658)
Cash flows from investing activities:
Capital expenditures	(1,668)	(429)	(460)
Contributions to equity method investees	0	0	0
Acquisition of gathering systems			0
Acquisitions of gathering systems from affiliate, net of acquired cash	(359,431)	(288,618)	(305,000)
Other, net	(394)	0	0
Advances to affiliates	(15,697)	(2,589)	(183)
Initial contribution to Ohio Gathering			0
Acquisition of Ohio Gathering Option			0
Option Exercise			0
Net cash used in investing activities	(377,190)	(291,636)	(305,643)
Cash flows from financing activities:
Distributions to unitholders	(167,504)	(152,074)	(122,224)
Borrowings under Revolving Credit Facility	12,000	180,000	57,000
Repayments under Revolving Credit Facility	0	(100,000)	(115,000)
Repayments under term loan		(182,500)	(100,000)
Borrowings under term loan			400,000
Debt issuance costs	0	(135)	(3,003)
Proceeds from issuance of common units, net	125,233	221,977	197,806
Contribution from General Partner	2,702	4,737	4,235
Cash advance (to) from Summit Investments (from) to contributed subsidiaries, net	(12,000)	102,500	(242,000)
Expenses paid by Summit Investments on behalf of contributed subsidiaries	3,030	12,655	12,845
Issuance of senior notes			0
Repurchase of equity-based compensation awards			(228)
Other, net	(1,182)	(1,615)	(656)
Advances from affiliates	405,845	198,224	221,766
Net cash provided by financing activities	368,124	283,769	310,541
Net change in cash and cash equivalents		(7,458)	1,240
Cash and cash equivalents, beginning of period	73	7,531	6,291
Cash and cash equivalents, end of period	698	73	7,531
Cash and Cash Equivalents, Period Increase (Decrease)	625
Co-Issuers | Reportable Legal Entities
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(58,254)	(46,716)	(30,689)
Cash flows from investing activities:
Capital expenditures	0	0	0
Contributions to equity method investees	0	0	0
Acquisition of gathering systems			0
Acquisitions of gathering systems from affiliate, net of acquired cash	0	0	0
Other, net	0	0	0
Advances to affiliates	(255,070)	(88,221)	(174,495)
Initial contribution to Ohio Gathering			0
Acquisition of Ohio Gathering Option			0
Option Exercise			0
Net cash used in investing activities	(255,070)	(88,221)	(174,495)
Cash flows from financing activities:
Distributions to unitholders	0	0	0
Borrowings under Revolving Credit Facility	508,300	187,000	237,295
Repayments under Revolving Credit Facility	(204,300)	(51,000)	(315,295)
Repayments under term loan		0	0
Borrowings under term loan			0
Debt issuance costs	(3,032)	(277)	(5,320)
Proceeds from issuance of common units, net	0	0	0
Contribution from General Partner	0	0	0
Cash advance (to) from Summit Investments (from) to contributed subsidiaries, net	0	0	0
Expenses paid by Summit Investments on behalf of contributed subsidiaries	0	0	0
Issuance of senior notes			300,000
Repurchase of equity-based compensation awards			0
Other, net	0	0	0
Advances from affiliates	0	0	0
Net cash provided by financing activities	300,968	135,723	216,680
Net change in cash and cash equivalents		786	11,496
Cash and cash equivalents, beginning of period	12,407	11,621	125
Cash and cash equivalents, end of period	51	12,407	11,621
Cash and Cash Equivalents, Period Increase (Decrease)	(12,356)
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	198,991	202,324	179,685
Cash flows from investing activities:
Capital expenditures	(49,378)	(118,458)	(220,360)
Contributions to equity method investees	0	0	0
Acquisition of gathering systems			(10,872)
Acquisitions of gathering systems from affiliate, net of acquired cash	0	0	0
Other, net	0	323	325
Advances to affiliates	(150,775)	(110,003)	(47,271)
Initial contribution to Ohio Gathering			0
Acquisition of Ohio Gathering Option			0
Option Exercise			0
Net cash used in investing activities	(200,153)	(228,138)	(278,178)
Cash flows from financing activities:
Distributions to unitholders	0	0	0
Borrowings under Revolving Credit Facility	0	0	0
Repayments under Revolving Credit Facility	0	0	0
Repayments under term loan		0	0
Borrowings under term loan			0
Debt issuance costs	0	0	0
Proceeds from issuance of common units, net	0	0	0
Contribution from General Partner	0	0	0
Cash advance (to) from Summit Investments (from) to contributed subsidiaries, net	0	21,719	81,421
Expenses paid by Summit Investments on behalf of contributed subsidiaries	0	3,864	10,483
Issuance of senior notes			0
Repurchase of equity-based compensation awards			0
Other, net	(121)	(192)	0
Advances from affiliates	0	0	0
Net cash provided by financing activities	(121)	25,391	91,904
Net change in cash and cash equivalents		(423)	(6,589)
Cash and cash equivalents, beginning of period	6,930	7,353	13,942
Cash and cash equivalents, end of period	5,647	6,930	7,353
Cash and Cash Equivalents, Period Increase (Decrease)	(1,283)
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	80,067	35,358	7,615
Cash flows from investing activities:
Capital expenditures	(91,673)	(153,338)	(122,560)
Contributions to equity method investees	(31,582)	(86,200)	(145,131)
Acquisition of gathering systems			0
Acquisitions of gathering systems from affiliate, net of acquired cash	0	0	0
Other, net	0	0	0
Advances to affiliates	0	0	0
Initial contribution to Ohio Gathering			(8,360)
Acquisition of Ohio Gathering Option			(190,000)
Option Exercise			(382,385)
Net cash used in investing activities	(123,255)	(239,538)	(848,436)
Cash flows from financing activities:
Distributions to unitholders	0	0	0
Borrowings under Revolving Credit Facility	0	0	0
Repayments under Revolving Credit Facility	0	0	0
Repayments under term loan		0	0
Borrowings under term loan			0
Debt issuance costs	0	0	0
Proceeds from issuance of common units, net	0	0	0
Contribution from General Partner	0	0	0
Cash advance (to) from Summit Investments (from) to contributed subsidiaries, net	24,214	196,308	834,962
Expenses paid by Summit Investments on behalf of contributed subsidiaries	1,791	6,360	1,556
Issuance of senior notes			0
Repurchase of equity-based compensation awards			0
Other, net	135	0	0
Advances from affiliates	15,697	2,589	183
Net cash provided by financing activities	41,837	205,257	836,701
Net change in cash and cash equivalents		1,077	(4,120)
Cash and cash equivalents, beginning of period	2,383	1,306	5,426
Cash and cash equivalents, end of period	1,032	$ 2,383	$ 1,306
Cash and Cash Equivalents, Period Increase (Decrease)	$ (1,351)

UNAUDITED QUARTERLY FINANCIA101

UNAUDITED QUARTERLY FINANCIAL DATA (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Limited Partners' Capital Account [Line Items]
Revenues	$ 127,083	$ 95,073	$ 89,635	$ 90,571	$ 112,414	$ 115,201	$ 86,855	$ 86,087	$ 402,362	$ 400,557	$ 387,169
Net loss attributable to SMLP	13,901	1,922	(50,287)	(6,454)	(220,468)	23,604	2,985	1,667	(40,918)	(192,212)	(23,992)
Less net loss and IDRs attributable to General Partner	2,379	2,137	935	1,810	(2,469)	2,408	1,891	1,568	7,261	3,398	3,125
Net loss attributable to limited partners	$ 11,522	$ (215)	$ (51,222)	$ (8,264)	(217,999)	21,196	$ 1,094	$ 99	(48,179)	(195,610)	(27,117)
(Loss) earnings per limited partner unit:
Goodwill impairment					248,900				0	248,851	54,199
Long-lived asset impairment					$ 1,600	7,700			1,764	9,305	5,505
Environmental remediation						$ 20,000			0	21,800	5,000
Common units
Limited Partners' Capital Account [Line Items]
Net loss attributable to limited partners									$ (48,179)	$ (125,437)	$ (16,324)
(Loss) earnings per limited partner unit:
Basic (in dollars per share)	$ 0.16	$ 0	$ (0.77)	$ (0.12)	$ (3.28)	$ 0.32	$ 0.05	$ 0	$ (0.71)	$ (3.20)	$ (0.49)
Diluted (in dollars per share)	$ 0.16	$ 0	$ (0.77)	$ (0.12)	(3.28)	0.32	0.05	0	(0.71)	$ (3.20)	$ (0.49)
Subordinated units
Limited Partners' Capital Account [Line Items]
Net loss attributable to limited partners										$ (70,173)	$ (10,793)
(Loss) earnings per limited partner unit:
Basic (in dollars per share)					$ (3.28)	$ 0.32	$ (0.03)	$ 0		$ (2.88)	$ (0.44)
Diluted (in dollars per share)										$ (2.88)	$ (0.44)
Previously Reported
Limited Partners' Capital Account [Line Items]
Revenues						$ 103,249	$ 77,274	$ 68,579
Bison Midstream | Adjustment
Limited Partners' Capital Account [Line Items]
Revenues						3,308	3,670	4,056
Polar and Divide Drop Down | Adjustment
Limited Partners' Capital Account [Line Items]
Revenues						0	0	8,582
Drop Down Assets 2016 Acquisition | Adjustment
Limited Partners' Capital Account [Line Items]
Revenues						$ 8,644	$ 5,911	$ 4,870
Consolidating adjustments
Limited Partners' Capital Account [Line Items]
Revenues									$ 0	$ 0	$ 0
(Loss) earnings per limited partner unit:
Goodwill impairment										0	0
Long-lived asset impairment									$ 0	0	0
Environmental remediation										$ 0	$ 0