Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Assets
Cash and cash equivalents	$ 63,343	$ 52,342
Restricted cash	10,855	10,096
Loans receivable, net	3,906,226	2,047,223
Equity investments in unconsolidated subsidiaries	14,990	22,480
Accrued interest receivable, prepaid expenses, and other assets	103,059	80,639
Total assets	4,098,473	2,212,780
Liabilities and equity
Accounts payable, accrued expenses, and other liabilities	83,011	97,153
Revolving repurchase facilities	1,669,406	863,622
Asset-specific repurchase agreements	226,961	245,731
Loan participations sold	447,977	90,000
Convertible notes, net	161,259	159,524
Total liabilities	2,588,614	1,456,030
Equity
Common stock	572	288
Additional paid-in capital	2,022,093	1,252,986
Accumulated other comprehensive (loss) income	(6,205)	798
Accumulated deficit	(538,726)	(536,170)
Total Blackstone Mortgage Trust, Inc. stockholders' equity	1,477,739	717,909
Non-controlling interests	32,120	38,841
Total equity	1,509,859	756,750
Total liabilities and equity	4,098,473	2,212,780
Restricted Class A Common Stock [Member]
Equity
Common stock	$ 5	$ 7