Fair Value of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Assets and liabilities measured at fair value
Derivative assets	$ 12,816	$ 337
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	144,163
Total investments:	481,596	550,020
Total Derivatives	(6,836)	(9,063)
Total	474,760	540,957
Fair value measurements on recurring basis | Total fair value | Foreign exchange contracts
Assets and liabilities measured at fair value
Derivative assets	5,261
Derivative Liabilities	(6,890)	(7,383)
Fair value measurements on recurring basis | Total fair value | Interest rate contracts
Assets and liabilities measured at fair value
Derivative assets	7,555	337
Derivative Liabilities	(12,762)	(2,017)
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	341,734	541,843
Fair value measurements on recurring basis | Total fair value | RMBS
Assets and liabilities measured at fair value
Available-for-sale securities	164,948	122,525
Fair value measurements on recurring basis | Total fair value | CMBS
Assets and liabilities measured at fair value
Available-for-sale securities	176,786	275,155
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	11,269	8,177
Fair value measurements on recurring basis | Level I
Assets and liabilities measured at fair value
Total investments:	11,269	8,177
Total	11,269	8,177
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	11,269	8,177
Fair value measurements on recurring basis | Level II
Assets and liabilities measured at fair value
Total investments:		397,680
Total Derivatives	(6,836)	(9,063)
Total	(6,836)	388,617
Fair value measurements on recurring basis | Level II | Foreign exchange contracts
Assets and liabilities measured at fair value
Derivative assets	5,261
Derivative Liabilities	(6,890)	(7,383)
Fair value measurements on recurring basis | Level II | Interest rate contracts
Assets and liabilities measured at fair value
Derivative assets	7,555	337
Derivative Liabilities	(12,762)	(2,017)
Fair value measurements on recurring basis | Level II | Available-for-sale debt securities
Assets and liabilities measured at fair value
Available-for-sale securities		397,680
Fair value measurements on recurring basis | Level II | RMBS
Assets and liabilities measured at fair value
Available-for-sale securities		122,525
Fair value measurements on recurring basis | Level II | CMBS
Assets and liabilities measured at fair value
Available-for-sale securities		275,155
Fair value measurements on recurring basis | Level III
Assets and liabilities measured at fair value
Loans held-for-sale at fair value	128,593	144,163
Total investments:	470,327	144,163
Total	470,327	144,163
Fair value measurements on recurring basis | Level III | Available-for-sale debt securities
Assets and liabilities measured at fair value
Available-for-sale securities	341,734	144,163
Fair value measurements on recurring basis | Level III | RMBS
Assets and liabilities measured at fair value
Available-for-sale securities	164,948
Fair value measurements on recurring basis | Level III | CMBS
Assets and liabilities measured at fair value
Available-for-sale securities	$ 176,786