Stockholders' Equity - Non-Vested Shares (Details)	9 Months Ended
	Sep. 30, 2017 $ / shares shares
Non-Vested Shares and Share Equivalents activity
Balance at the beginning of the period (in shares)	820,374
Granted (in shares)	1,548,160
Vested (in shares)	(672,608)
Forfeited (in shares)	(34,531)
Balance at the end of the period (in shares)	1,661,395
Weighted Average Grant Date Fair Value (per share)
Balance at the beginning of period (in dollars per share) | $ / shares	$ 22.34
Granted (in dollars per share) | $ / shares	22.27
Vested (in dollars per share) | $ / shares	22.69
Forfeited (in dollars per share) | $ / shares	22.56
Balance at the end of period (in dollars per share) | $ / shares	$ 22.09
Starwood Property Trust, Inc. Equity Plan
Non-Vested Shares and Share Equivalents activity
Balance at the beginning of the period (in shares)	539,124
Granted (in shares)	548,160
Vested (in shares)	(337,192)
Forfeited (in shares)	(34,531)
Balance at the end of the period (in shares)	715,561
Starwood Property Trust, Inc. Manager Equity Plan
Non-Vested Shares and Share Equivalents activity
Balance at the beginning of the period (in shares)	281,250
Granted (in shares)	1,000,000
Vested (in shares)	(335,416)
Balance at the end of the period (in shares)	945,834