Fair Value of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Assets and liabilities measured at fair value
Derivative assets	$ 9,795	$ 12,816
Fair value measurements on recurring basis | Total fair value
Assets and liabilities measured at fair value
Loans held-for-sale at fair value		128,593
Total investments:	919,975	481,596
Total Derivatives	(5,038)	(6,836)
Total	914,937	474,760
Fair value measurements on recurring basis | Total fair value | Foreign exchange contracts
Assets and liabilities measured at fair value
Derivative assets	3,477	5,261
Derivative Liabilities	(10,254)	(6,890)
Fair value measurements on recurring basis | Total fair value | Interest rate contracts
Assets and liabilities measured at fair value
Derivative assets	6,318	7,555
Derivative Liabilities	(4,579)	(12,762)
Fair value measurements on recurring basis | Total fair value | Available-for-sale debt securities
Assets and liabilities measured at fair value
Available-for-sale securities	908,505	341,734
Fair value measurements on recurring basis | Total fair value | RMBS
Assets and liabilities measured at fair value
Available-for-sale securities	233,456	164,948
Fair value measurements on recurring basis | Total fair value | CMBS
Assets and liabilities measured at fair value
Available-for-sale securities	675,049	176,786
Fair value measurements on recurring basis | Total fair value | Available-for-sale equity securities, Real estate industry
Assets and liabilities measured at fair value
Available-for-sale securities	11,470	11,269
Fair value measurements on recurring basis | Total fair value | Total available-for-sale equity securities
Assets and liabilities measured at fair value
Available-for-sale securities	11,470	11,269
Fair value measurements on recurring basis | Level I
Assets and liabilities measured at fair value
Total investments:	11,470	11,269
Total	11,470	11,269
Fair value measurements on recurring basis | Level I | Available-for-sale equity securities, Real estate industry
Assets and liabilities measured at fair value
Available-for-sale securities	11,470	11,269
Fair value measurements on recurring basis | Level I | Total available-for-sale equity securities
Assets and liabilities measured at fair value
Available-for-sale securities	11,470	11,269
Fair value measurements on recurring basis | Level II
Assets and liabilities measured at fair value
Total investments:	675,049
Total Derivatives	(5,038)	(6,836)
Total	670,011	(6,836)
Fair value measurements on recurring basis | Level II | Foreign exchange contracts
Assets and liabilities measured at fair value
Derivative assets	3,477	5,261
Derivative Liabilities	(10,254)	(6,890)
Fair value measurements on recurring basis | Level II | Interest rate contracts
Assets and liabilities measured at fair value
Derivative assets	6,318	7,555
Derivative Liabilities	(4,579)	(12,762)
Fair value measurements on recurring basis | Level II | Available-for-sale debt securities
Assets and liabilities measured at fair value
Available-for-sale securities	675,049
Fair value measurements on recurring basis | Level II | CMBS
Assets and liabilities measured at fair value
Available-for-sale securities	675,049
Fair value measurements on recurring basis | Level III
Assets and liabilities measured at fair value
Loans held-for-sale at fair value		128,593
Total investments:	233,456	470,327
Total	233,456	470,327
Fair value measurements on recurring basis | Level III | Available-for-sale debt securities
Assets and liabilities measured at fair value
Available-for-sale securities	233,456	341,734
Fair value measurements on recurring basis | Level III | RMBS
Assets and liabilities measured at fair value
Available-for-sale securities	233,456	164,948
Fair value measurements on recurring basis | Level III | CMBS
Assets and liabilities measured at fair value
Available-for-sale securities		$ 176,786