Consolidated Statements of Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Statement [Abstract]
Net income	$ 38,439	$ 6,768	$ 51,555	$ 5,170
Other comprehensive income:
Unrealized gain on foreign currency remeasurement	1,894		1,930
Other comprehensive income	1,894		1,930
Comprehensive income	40,333	6,768	53,485	5,170
Comprehensive income attributable to non-controlling interests	(4,973)	(4,020)	(5,024)	(5,537)
Comprehensive income (loss) attributable to Blackstone Mortgage Trust, Inc.	$ 35,360	$ 2,748	$ 48,461	$ (367)