Redeemable Non-Controlling Interests in Consolidated Subsidiaries and Funds (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries and funds	$ 379,205				$ 186,911				$ 379,205	$ 186,911
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	9,406	$ 18,478	$ (16,705)	$ (4,297)	4,266	$ 4,344	$ 3,916	$ 2,720	6,882	15,246	$ 15,564
Operating Entities
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries and funds	7,638				10,906				7,638	10,906
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds									3,717	9,503	10,094
Consolidated Funds
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries and funds	$ 371,567				$ 176,005				371,567	176,005
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds									$ 3,165	$ 5,743	$ 5,470