Stockholders' Equity - Non-Vested Shares (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016
Non-Vested Shares and Share Equivalents activity
Beginning Balance (in shares)	1,868,216
Granted (in shares)	458,264
Vested (in shares)	(1,453,269)
Forfeited (in shares)	(52,837)
Balance at the end of period (in shares)	820,374	1,868,216
Weighted Average Grant Date Fair Value (per share)
Balance at the beginning of period (in dollars per share)	$ 25.84
Granted (in dollars per share)	19.13	$ 24.20	$ 27.91
Vested (in dollars per share)	25.81
Forfeited (in dollars per share)	22.63
Balance at the end of period (in dollars per share)	$ 22.34	$ 25.84
Vesting Schedule
2017 (in shares)				556,899
2018 (in shares)				188,164
2019 (in shares)				75,311
Total	1,868,216	1,868,216		820,374
Total unrecognized compensation costs related to unvested share-based compensation				$ 13.2
Total fair value of shares vested	$ 30.2	$ 28.3	$ 28.6
Period over which unrecognized compensation cost is expected to be recognized	10 months 24 days
Starwood Property Trust, Inc. Equity Plan
Non-Vested Shares and Share Equivalents activity
Beginning Balance (in shares)	548,378
Granted (in shares)	436,700
Vested (in shares)	(410,905)
Forfeited (in shares)	(52,837)
Balance at the end of period (in shares)	521,336	548,378
Vesting Schedule
2017 (in shares)				314,111
2018 (in shares)				131,914
2019 (in shares)				75,311
Total	548,378	548,378		521,336
Award vesting period	3 years
Starwood Property Trust, Inc. Manager Equity Plan
Non-Vested Shares and Share Equivalents activity
Beginning Balance (in shares)	1,302,850
Vested (in shares)	(1,021,600)
Balance at the end of period (in shares)	281,250	1,302,850
Vesting Schedule
2017 (in shares)				225,000
2018 (in shares)				56,250
Total	1,302,850	1,302,850		281,250
Starwood Property Trust, Inc. Non-Executive Director Stock Plan
Non-Vested Shares and Share Equivalents activity
Beginning Balance (in shares)	16,988
Granted (in shares)	21,564
Vested (in shares)	(20,764)
Balance at the end of period (in shares)	17,788	16,988
Vesting Schedule
2017 (in shares)				17,788
Total	16,988	16,988		17,788