Consolidated Securitization Vehicles (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended					9 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Securitization Vehicles	Dec. 31, 2011 Securitization Vehicles		Sep. 30, 2012 Securitization Vehicles CMBS	Dec. 31, 2011 Securitization Vehicles CMBS	Sep. 30, 2012 Securitization Vehicles CDOs & Other	Dec. 31, 2011 Securitization Vehicles CDOs & Other
Amortized cost basis					$ 167,133			$ 136,933		$ 30,200
Mark-to-market adjustments on securities previously classified as available-for-sale					6			6
Other-than-temporary impairments recognized in accumulated other comprehensive income		(173)	160	3,098	(12,291)			(12,291)
Securities held-to-maturity					$ 154,848	$ 358,972	[1]	$ 124,648	$ 357,037	$ 30,200	$ 1,935

[1] Includes securities with a total face value of $236.4 million and $490.9 million as of September 30, 2012 and December 31, 2011, respectively.