Redeemable Non-Controlling Interests in Consolidated Subsidiaries and Funds (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries and funds	$ 348,424		$ 348,424		$ 216,923
Nonredeemable Noncontrolling Interest	433,183		433,183		281,803
Net Income (Loss) Attributable to Noncontrolling Interest	2,770	$ 4,110	7,188	$ 37,798
Operating Entities
Noncontrolling Interest [Line Items]
Nonredeemable Noncontrolling Interest	15,268		15,268		7,457
Net Income (Loss) Attributable to Noncontrolling Interest	(2,126)	1,306	(1,586)	2,805
Consolidated Funds
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries and funds	348,424		348,424		216,923
Nonredeemable Noncontrolling Interest	69,491		69,491		$ 57,423
Net Income (Loss) Attributable to Noncontrolling Interest	$ 4,896	$ 2,804	$ 8,774	$ 34,993