Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Assets
Cash and cash equivalents	$ 10,283	$ 15,423
Restricted cash	76,396	14,246
Loans receivable, net	1,362,891	141,500
Loans receivable, at fair value	66,063
Investment in CT Legacy Asset, at fair value		132,000
Equity investments in unconsolidated subsidiaries	25,632	13,306
Accrued interest receivable, prepaid expenses, and other assets	36,045	5,868
Total assets	1,577,310	322,343
Liabilities
Accounts payable, accrued expenses and other liabilities	47,495	21,209
Secured notes	9,030	8,497
Repurchase obligations	643,040
Securitized debt obligations	74,203	139,184
Total liabilities	773,768	168,890
Equity
Class A common stock, $0.01 par value, 100,000 shares authorized, 28,802 and 2,927 shares issued and outstanding as of September 30, 2013 and December 31, 2012, respectively	288	293
Additional paid-in capital	1,242,986	609,002
Accumulated deficit	(529,947)	(535,851)
Total Blackstone Mortgage Trust, Inc. stockholders' equity	713,327	73,444
Non-controlling interests	90,215	80,009
Total equity	803,542	153,453
Total liabilities and equity	1,577,310	322,343
Variable Interest Entity, Primary Beneficiary [Member]
Assets
Loans receivable, net	77,000	141,500
Accrued interest receivable, prepaid expenses, and other assets	6,336	4,021
Total assets	83,336	145,521
Liabilities
Accounts payable, accrued expenses and other liabilities	40	88
Securitized debt obligations	74,203	139,184
Total liabilities	$ 74,243	$ 139,272