Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Net income	$ 69,450	$ 32,417	$ 126,649	$ 78,512
Other comprehensive loss
Unrealized (loss) gain on foreign currency remeasurement	(21,321)	15,732	(15,343)	(4,336)
Unrealized gain (loss) on derivative financial instruments	12,624	(3,308)	5,958	28
Comprehensive income	60,753	44,841	117,264	74,204
Comprehensive income attributable to non-controlling interests	(6,369)	(3,133)	(6,521)	(13,833)
Comprehensive income attributable to Blackstone Mortgage Trust, Inc.	$ 54,384	$ 41,708	$ 110,743	$ 60,371