CONDENSED CONSOLIDATED STATEMENTS OF PARTNERS' CAPITAL - USD ($) $ in Thousands	Total	Accumulated Other Comprehensive (Loss) Income	Noncontrolling Interests	Limited Partners
Beginning balance at Dec. 31, 2017	$ 4,868,322	$ 28,631	$ 277,385	$ 4,562,306
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	117,092		4,719	112,373
Distributions paid to unitholders	(186,069)		695	(186,764)
Net proceeds from issuance of Units	262,066			262,066
Amortization of unit-based compensation awards	8,764			8,764
Payment of tax withholding on vesting of LTIP awards	(6,596)			(6,596)
Distributions paid to noncontrolling interests	(7,759)		(7,759)
Contributions from noncontrolling interests	4,400		4,400
Other comprehensive income	30,456	30,456
Accrual of distribution equivalent rights	(1,488)			(1,488)
Ending balance at Mar. 31, 2018	5,089,188	59,087	279,440	4,750,661
Beginning balance at Dec. 31, 2018	4,131,170	(40,061)	11,088	4,160,143
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	81,260		498	80,762
Distributions paid to unitholders	(115,852)		378	(116,230)
Amortization of unit-based compensation awards	9,912			9,912
Payment of tax withholding on vesting of LTIP awards	(2,245)			(2,245)
Distributions paid to noncontrolling interests	(947)		(947)
Other comprehensive income	1,642	1,642
Accrual of distribution equivalent rights	(541)			(541)
Other	(3)			(3)
Ending balance at Mar. 31, 2019	$ 4,104,396	$ (38,419)	$ 11,017	$ 4,131,798