Redeemable Noncontrolling Interests and Equity - Schedule of Changes in Redeemable Noncontrolling Interest,Total Stockholders' Equity and Noncontrolling Interests (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($) fund	Jun. 30, 2017 USD ($)
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period	$ 123,801
Balance at end of period	129,929
Balance at beginning of period	1,240,516	$ 995,728
Cumulative effect of adoption of ASU 2016-16 and ASU 2016-09		2,996
Exercise of stock options	8,068	529
Issuance of restricted stock units, net of tax withholdings	(4,878)	(2,099)
Shares issued in connection with the Employee Stock Purchase Plan	1,755	1,145
Stock based compensation	16,251	11,416
Contributions from noncontrolling interests and redeemable noncontrolling interests	116,021	231,123
Distributions to noncontrolling interests and redeemable noncontrolling interests	(29,396)	(19,527)
Net income (loss)	(123,213)	(104,399)
Other comprehensive loss, net of taxes	20,197	(3,569)
Balance at end of period	$ 1,245,321	1,113,343
Number of funds, carrying value adjusted to redemption value | fund	5
Redeemable Noncontrolling Interests
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period	$ 123,801	140,996
Contributions from redeemable noncontrolling interests	51,447	75,169
Distributions to redeemable noncontrolling interests	(5,385)	(7,666)
Net income (loss)	(39,934)	(44,366)
Balance at end of period	129,929	164,133
Total Stockholders' Equity
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period	881,582	742,771
Cumulative effect of adoption of ASU 2016-16 and ASU 2016-09		2,996
Exercise of stock options	8,068	529
Issuance of restricted stock units, net of tax withholdings	(4,878)	(2,099)
Shares issued in connection with the Employee Stock Purchase Plan	1,755	1,145
Stock based compensation	16,251	11,416
Net income (loss)	35,441	28,228
Other comprehensive loss, net of taxes	20,197	(3,569)
Balance at end of period	958,416	781,417
Noncontrolling Interests
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period	358,934	252,957
Contributions from noncontrolling interests and redeemable noncontrolling interests	116,021	231,123
Distributions to noncontrolling interests and redeemable noncontrolling interests	(29,396)	(19,527)
Net income (loss)	(158,654)	(132,627)
Balance at end of period	$ 286,905	$ 331,926