Condensed Consolidated Statements of Changes in Unitholders' Capital (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2015
Increase (decrease) in Stockholders' Equity:
Unitholders' capital, value			$ 1,885,171	$ 1,808,094
Cumulative-effect adjustment from adoption of accounting guidance					$ (122,621)
Repurchase and cancellation of units			(9,697)	(10,315)
Equity reallocation between controlling and non-controlling interests	$ 2,562	$ (645)	(9,499)	(8,126)
Capital increase related to equity-based compensation			29,035	28,413
Distributions declared			(243,913)	(184,934)
Net income			444,671	222,013
Foreign currency translation adjustment, net of tax	(997)	2,488	(5,654)	3,581
Unrealized gain on interest-rate swap designated as cash-flow hedge, net of tax		215	60	195
Unitholders' capital, value	2,099,673	1,744,426	2,099,673	1,744,426
Paid-in Capital
Increase (decrease) in Stockholders' Equity:
Unitholders' capital, value			749,618	735,166
Cumulative-effect adjustment from adoption of accounting guidance					(12,912)
Repurchase and cancellation of units			(7,194)	(10,089)
Equity reallocation between controlling and non-controlling interests			9,499	8,126
Capital increase related to equity-based compensation			11,895	11,455
Distributions declared				(1,350)
Unitholders' capital, value	763,466	730,396	763,466	730,396
Retained Earnings
Increase (decrease) in Stockholders' Equity:
Unitholders' capital, value			54,494	0
Distributions declared			(85,942)	(62,197)
Net income			172,239	77,125
Unitholders' capital, value	141,143	14,928	141,143	14,928
Accumulated Other Comprehensive Income (Loss)
Increase (decrease) in Stockholders' Equity:
Unitholders' capital, value			1,793	(1,216)
Foreign currency translation adjustment, net of tax			(2,293)	1,446
Unrealized gain on interest-rate swap designated as cash-flow hedge, net of tax			24	79
Unitholders' capital, value	(476)	309	(476)	309
Non-controlling Interests in Consolidated Subsidiaries
Increase (decrease) in Stockholders' Equity:
Unitholders' capital, value			1,050,319	1,043,930
Cumulative-effect adjustment from adoption of accounting guidance					$ (109,709)
Repurchase and cancellation of units			(2,503)	(226)
Equity reallocation between controlling and non-controlling interests			(9,499)	(8,126)
Capital increase related to equity-based compensation			17,140	16,958
Distributions declared			(156,826)	(119,708)
Net income			271,482	144,502
Foreign currency translation adjustment, net of tax	(601)	1,484	(3,361)	2,135
Unrealized gain on interest-rate swap designated as cash-flow hedge, net of tax		128	36	116
Unitholders' capital, value	1,166,788	969,872	1,166,788	969,872
Non-controlling Interests in Consolidated Funds
Increase (decrease) in Stockholders' Equity:
Unitholders' capital, value			28,947	30,214
Distributions declared			(1,145)	(1,679)
Net income			950	386
Foreign currency translation adjustment, net of tax	0	0	0	0
Unrealized gain on interest-rate swap designated as cash-flow hedge, net of tax		0	0	0
Unitholders' capital, value	$ 28,752	$ 28,921	$ 28,752	$ 28,921
Class A Units
Increase (decrease) in Stockholders' Equity:
Unitholders' capital, shares			63,032	61,970
Issuance of units, shares			1,350	897
Cancellation of units associated with forfeitures, shares			(17)	(41)
Repurchase and cancellation of units, shares			(180)	(223)
Unitholders' capital, shares	64,185	62,603	64,185	62,603
Class B Units
Increase (decrease) in Stockholders' Equity:
Unitholders' capital, shares			91,758	91,938
Issuance of units, shares			496	630
Cancellation of units associated with forfeitures, shares				(111)
Cancellation of units, shares			(140)	(110)
Repurchase and cancellation of units, shares			(71)	(6)
Unitholders' capital, shares	92,043	92,341	92,043	92,341