Stockholders' Equity (Details 2) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Gross investment in CT Legacy Partners:
Restricted cash	$ 12,719	$ 14,246
Loans receivable, at fair value	150,332
Accrued interest receivable, prepaid expenses and other assets	13,693	5,868
Accounts payable, accrued expenses and other liabilities	(30,760)	(21,209)
Repurchase obligations	(20,214)
Interest rate swap liabilities	(6,119)
Noncontrolling interests in CT Legacy Partners	86,350	80,009
Noncontrolling Interests
Gross investment in CT Legacy Partners:
Restricted cash	12,719
Securities held-to-maturity	11,702
Loans receivable, at fair value	150,332
Accrued interest receivable, prepaid expenses and other assets	8,879
Accounts payable, accrued expenses and other liabilities	(815)
Repurchase obligations	(20,214)
Interest rate swap liabilities	(6,119)
Investment in CT Legacy REIT, Gross	156,484
Equity interests owned by Blackstone Mortgage Trust, Inc.	(70,134)
Noncontrolling interests in CT Legacy Partners	$ 86,350

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