Fair Value of Financial Instruments (Details 3) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Derivative Financial Instruments, Assets [Member]
Balance as of December 31, 2012	$ 173
Change in CMBS investment status	0
Amortization of discounts or premiums	0
Proceeds from CMBS principal repayments	0
Gramercy Finance disposal	(219)
Adjustments to fair value:
Included in other comprehensive income	46
Other-than-temporary impairments	0
Balance as of June 30, 2013	0
Commercial Mortgage Backed Securities [Member] | External Credit Rating, Investment Grade [Member]
Balance as of December 31, 2012	281,495
Change in CMBS investment status	(1,506)
Amortization of discounts or premiums	1,264
Proceeds from CMBS principal repayments	(10,526)
Gramercy Finance disposal	(274,133)
Adjustments to fair value:
Included in other comprehensive income	3,406
Other-than-temporary impairments	0
Balance as of June 30, 2013	0
Commercial Mortgage Backed Securities [Member] | External Credit Rating, Non Investment Grade [Member]
Balance as of December 31, 2012	650,770
Change in CMBS investment status	1,506
Amortization of discounts or premiums	6,075
Proceeds from CMBS principal repayments	0
Gramercy Finance disposal	(670,387)
Adjustments to fair value:
Included in other comprehensive income	19,677
Other-than-temporary impairments	(7,641)
Balance as of June 30, 2013	0
Collateralized Debt Obligations Bonds [Member]
Balance as of December 31, 2012	0
Change in CMBS investment status	0
Amortization of discounts or premiums	652
Proceeds from CMBS principal repayments	0
Gramercy Finance disposal	8,492
Adjustments to fair value:
Included in other comprehensive income	183
Other-than-temporary impairments	(1,682)
Balance as of June 30, 2013	$ 7,645