CONDENSED CONSOLIDATED STATEMENTS OF PARTNERS' CAPITAL - USD ($) $ in Thousands	Total	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests	Limited Partners	Class C Units Limited Partners
Beginning balance at Dec. 31, 2016	$ 4,698,423	$ (25,593)	$ 286,700	$ 4,437,316	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	242,688		6,390	236,298
Distributions paid to unitholders	(350,260)		1,458	(351,718)
Net proceeds from issuance of units	48,440			48,440
Amortization of unit-based compensation awards	17,665			17,665
Payment of tax withholding on vesting of LTIP awards	(8,305)			(8,305)
Net proceeds from exercise of Unit options	481			481
Distributions paid to noncontrolling interests	(16,892)		(16,892)
Contributions from noncontrolling interests	5,600		5,600
Other comprehensive income	27,606	27,606
Accrual of distribution equivalent rights	(1,972)			(1,972)
Other			37	(37)
Ending balance at Jun. 30, 2017	4,663,474	2,013	283,293	4,378,168	0
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	210,409		6,132	198,923	5,354
Acquisition of noncontrolling interest	(210,000)		(267,006)	54,660	(2,346)
Distributions paid to unitholders	(372,157)		1,372	(373,529)
In-kind distribution to unitholders				(8,469)	8,469
Net proceeds from issuance of units	262,086				262,086
Amortization of unit-based compensation awards	16,772			16,772
Payment of tax withholding on vesting of LTIP awards	(6,728)			(6,728)
Distributions paid to noncontrolling interests	(14,034)		(14,034)
Contributions from noncontrolling interests	7,400		7,400
Other comprehensive income	19,949	19,949
Accrual of distribution equivalent rights	(2,386)			(2,386)
Other	(44)			(44)
Ending balance at Jun. 30, 2018	$ 4,779,589	$ 48,580	$ 11,249	$ 4,441,505	$ 278,255