UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF PARTNERS' CAPITAL - USD ($) $ in Thousands	Total	Series A Preferred Units Noncontrolling Interest	Common Noncontrolling Interest Noncontrolling Interest	Partners' Capital	Partners' Capital Series A Preferred Units
Beginning balance at Dec. 31, 2019	$ 785,236	$ 293,616	$ 186,070	$ 305,550
Net income (loss)	2,817	7,125	(1,881)	(2,427)
Net cash distributions to SMLP unitholders	(6,037)		(6,037)
Unit-based compensation	2,723		2,723
Effect of common unit issuances under SMLP LTIP			2,322	(2,322)
Tax withholdings and associated payments on vested SMLP LTIP awards	(984)		(984)
Ending balance at Mar. 31, 2020	783,755	$ 300,741	$ 182,213	300,801
Beginning balance at Dec. 31, 2020	922,891			748,466	$ 174,425
Net income (loss)	5,056			769	4,287
Unit-based compensation	1,967			1,967
Tax withholdings and associated payments on vested SMLP LTIP awards	(1,274)			(1,274)
Ending balance at Mar. 31, 2021	$ 928,640			$ 749,928	$ 178,712