Unaudited Condensed Consolidated Statements of Partners' Capital - USD ($) $ in Thousands	Total	Partners’ Capital	Noncontrolling Interest	Accumulated Other Comprehensive Loss	Common Units Partners’ Capital
Partners' capital, beginning balance (units) at Dec. 31, 2016					117,979,000
Partners' capital, beginning balance at Dec. 31, 2016	$ 2,120,050	$ 2,130,331	$ (10,281)	$ 0
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	26,938	27,090	(152)	0	$ 0
Cash distributions to partners	(83,765)	(83,765)	0	0	$ 0
Issuance of common units for cash, net (units)					4,600,000
Issuance of common units for cash, net	140,537	140,537	0	0
Partners' capital, ending balance (units) at Mar. 31, 2017					122,579,000
Partners' capital, ending balance at Mar. 31, 2017	2,203,760	2,214,193	(10,433)	0
Increase (Decrease) in Partners' Capital [Roll Forward]
Impact of adoption of ASC 606 | Scenario, Adjustment | ASC 606	(3,550)	(3,550)	0	0	$ 0
Partners' capital, adjusted beginning balance	$ 2,013,914	2,022,597	(8,079)	(604)
Partners' capital, beginning balance (units) (Scenario, Previously Reported) at Dec. 31, 2017					122,579,000
Partners' capital, beginning balance (units) at Dec. 31, 2017	122,579,218				122,579,000
Partners' capital, beginning balance (Scenario, Previously Reported) at Dec. 31, 2017	$ 2,017,464	2,026,147	(8,079)	(604)
Partners' capital, beginning balance at Dec. 31, 2017	2,017,464
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	7,898	8,034	(136)	0	$ 0
Cash distributions to partners	(62,515)	(62,515)	0	0	0
Cash contributions from noncontrolling interests	400	0	400	0	0
Distributions to Class A Convertible Preferred unitholders	$ (16,526)	(16,526)	0	0	$ 0
Partners' capital, ending balance (units) at Mar. 31, 2018	122,579,218				122,579,000
Partners' capital, ending balance at Mar. 31, 2018	$ 1,943,171	$ 1,951,590	$ (7,815)	$ (604)