Redeemable Noncontrolling Interests and Equity - Schedule of Changes in Redeemable Noncontrolling Interest,Total Stockholders' Equity and Noncontrolling Interests (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) fund	Mar. 31, 2017 USD ($)
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period	$ 123,801
Balance at end of period	133,524
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	1,908	101
Issuance of restricted stock units, net of tax withholdings	(2,484)	(1,168)
Stock based compensation	10,703	5,887
Contributions from noncontrolling interests	112,501	130,144
Distributions to noncontrolling interests	(14,206)	(9,547)
Net income (loss)	(72,648)	(46,298)
Other comprehensive loss, net of taxes	14,938	(201)
Balance at end of period	$ 1,291,228	1,077,642
Number of funds, carrying value adjusted to redemption value | fund	6
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	31,103	35,168
Distributions to redeemable noncontrolling interests	(2,608)	(3,843)
Net income (loss) attributable to redeemable noncontrolling interests	(18,772)	(28,857)
Balance at end of period	133,524	143,464
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	1,908	101
Issuance of restricted stock units, net of tax withholdings	(2,484)	(1,168)
Stock based compensation	10,703	5,887
Net income (loss)	28,032	9,882
Other comprehensive loss, net of taxes	14,938	(201)
Balance at end of period	934,679	760,268
Noncontrolling Interests
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period	358,934	252,957
Contributions from noncontrolling interests	112,501	130,144
Distributions to noncontrolling interests	(14,206)	(9,547)
Net income (loss)	(100,680)	(56,180)
Balance at end of period	$ 356,549	$ 317,374