Consolidated Investment Products (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Jun. 30, 2011	Jun. 30, 2011	Sep. 30, 2012	Dec. 31, 2011
Percentage of VIE general partnership interest				1.00%
Pay interest at Libor or Euribor plus				14.00%
Collateral assets, default percentage				1.00%	1.00%
Weighted average maturity (years)				9.0
Notes issued by collateralized loan obligations terms of arrangements interest rate margin spread low				0.21%
Notes issued by collateralized loan obligations terms of arrangements interest rate margin spread high				7.10%
Outstanding balance on the notes issued by consolidated CLOs exceeds their fair value by approximately				$ 400,000,000	$ 1,000,000,000
Gain (loss) on derivative instruments, net, pretax	3,800,000	4,200,000	1,500,000	10,500,000
Derivative instruments, number of open swap agreements					70
Derivative instruments, open swap agreements, notional value					123,300,000
2015 [Member]
CLOs mature at various dates				2015
2024 [Member]
CLOs mature at various dates				2023
Senior Secured Bank Loans And Bonds [Member]
Fair value, option, aggregate differences, long-term debt instruments	$ 163,000,000			$ 163,000,000	$ 701,000,000