UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF PARTNERS' CAPITAL - USD ($) $ in Thousands	Total	Adjustment	Noncontrolling interest	Noncontrolling interest Adjustment	Common	Common Adjustment	General Partner	General Partner Adjustment	Limited partners, Series A Preferred Units	Limited partners, Series A Preferred Units Adjustment
Beginning balance at Dec. 31, 2016	$ 1,169,673		$ 11,247		$ 1,129,132		$ 29,294
Net income (loss)	104,300		282		95,576		8,442
Distributions to unitholders	(134,066)		0		(125,052)		(9,014)
Unit-based compensation	5,902		0		5,902		0
Tax withholdings on vested SMLP LTIP awards	(2,051)		0		(2,051)		0
ATM Program issuances, net of costs	17,251		0		17,251		0
Contribution from General Partner	465		0		0		465
Other	(166)		0		(166)		0
Ending balance at Sep. 30, 2017	1,161,308		11,529		1,120,592		29,187
January 1, 2018 impact of Topic 606day 1 adoption	4,214		0		4,130		84		$ 0
Beginning balance at Dec. 31, 2017	1,389,669	$ 1,393,883	10,813	$ 10,813	1,056,510	$ 1,060,640	27,920	$ 28,004	294,426	$ 294,426
Net income (loss)	3,697		168		(24,323)		6,477		21,375
Distributions to unitholders	(149,734)		0		(126,383)		(9,101)		(14,250)
Unit-based compensation	5,948		0		5,948		0		0
Tax withholdings on vested SMLP LTIP awards	(1,840)		0		(1,840)		0		0
Other	(939)		0		(129)		0		(810)
Ending balance at Sep. 30, 2018	$ 1,251,015		$ 10,981		$ 913,913		$ 25,380		$ 300,741