Fair Value of Financial Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Financial Assets:	$ 0	[1]	$ 173	[1]
CMBS available for sale:	0	[1]	932,265	[1]
Retained CDO Bonds:	7,645		0
Financial Liabilities:	0		173,623
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Financial Assets:	0		0
CMBS available for sale:	0		0
Retained CDO Bonds:	0
Financial Liabilities:	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Financial Assets:	0		0
CMBS available for sale:	0		0
Retained CDO Bonds:	0
Financial Liabilities:	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Assets:	0		173
CMBS available for sale:	0		932,265
Retained CDO Bonds:	7,645
Financial Liabilities:	0		173,623
Fair Value, Measurements, Recurring [Member] | Interest Rate Cap [Member]
Financial Assets:	0		173
Financial Liabilities:	0		173,623
Fair Value, Measurements, Recurring [Member] | Interest Rate Cap [Member] | Fair Value, Inputs, Level 1 [Member]
Financial Assets:	0		0
Financial Liabilities:	0		0
Fair Value, Measurements, Recurring [Member] | Interest Rate Cap [Member] | Fair Value, Inputs, Level 2 [Member]
Financial Assets:	0		0
Financial Liabilities:	0		0
Fair Value, Measurements, Recurring [Member] | Interest Rate Cap [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Assets:	0		173
Financial Liabilities:	0		173,623
Fair Value, Measurements, Recurring [Member] | Interest Rate Swap [Member]
Financial Assets:	0		0
Financial Liabilities:	0		0
Fair Value, Measurements, Recurring [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Financial Assets:	0		0
Financial Liabilities:	0		0
Fair Value, Measurements, Recurring [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Financial Assets:	0		0
Financial Liabilities:	0		0
Fair Value, Measurements, Recurring [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Assets:	0		0
Financial Liabilities:	0		0
Collateralized Debt Obligations Bonds [Member] | Fair Value, Measurements, Recurring [Member]
Retained CDO Bonds:	7,645
Collateralized Debt Obligations Bonds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Retained CDO Bonds:	0
Collateralized Debt Obligations Bonds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Retained CDO Bonds:	0
Collateralized Debt Obligations Bonds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Retained CDO Bonds:	7,645
External Credit Rating, Investment Grade [Member] | Fair Value, Measurements, Recurring [Member]
CMBS available for sale:	0		281,495
External Credit Rating, Investment Grade [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
CMBS available for sale:	0		0
External Credit Rating, Investment Grade [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
CMBS available for sale:	0		0
External Credit Rating, Investment Grade [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
CMBS available for sale:	0		281,495
External Credit Rating, Non Investment Grade [Member] | Fair Value, Measurements, Recurring [Member]
CMBS available for sale:	0		650,770
External Credit Rating, Non Investment Grade [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
CMBS available for sale:	0		0
External Credit Rating, Non Investment Grade [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
CMBS available for sale:	0		0
External Credit Rating, Non Investment Grade [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
CMBS available for sale:	$ 0		$ 650,770

[1] In connection with the disposal of Gramercy Finance, lending investments, CMBS investments, derivative instruments, and collateralized debt obligations were classified as held-for-sale as of December 31, 2012.