Redeemable Non-Controlling Interests in Consolidated Subsidiaries (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries	$ 91,429,000		$ 91,429,000		$ 85,814,000
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	4,006,000	4,759,000	13,409,000	10,509,000
Operating Entities
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries	11,721,000		11,721,000		12,009,000
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	3,223,000	3,884,000	9,690,000	7,280,000
Consolidated Funds
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries	79,708,000		79,708,000		73,805,000
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	783,000	875,000	3,719,000	3,229,000
Orchard Square Partners [Member]
Noncontrolling Interest [Line Items]
Assets under Management, Carrying Amount	$ 448,000,000		$ 448,000,000