Redeemable Non-Controlling Interests in Consolidated Subsidiaries (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries	$ 85,814				$ 85,703				$ 85,814	$ 85,703
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	2,684	4,759	2,255	3,495	1,154	(1,033)	(2,434)	2,241	13,193	(72)	5,827
Operating Entities
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries	12,009				4,106				12,009	4,106
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds									10,461	301	7,002
Consolidated Funds
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries	73,805				81,597				73,805	81,597
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds									$ 2,732	$ (373)	$ (1,175)