Stockholders' Equity and Non-Controlling Interests - Non-Vested Shares (Details)	3 Months Ended
	Mar. 31, 2021 $ / shares shares
Non-Vested Shares and Share Equivalents activity
Balance at the beginning of the period (in shares)	3,881,501
Granted (in shares)	1,518,072
Vested (in shares)	(930,235)
Balance at the end of the period (in shares)	4,469,338
Weighted Average Grant Date Fair Value (per share)
Balance at the beginning of period (in dollars per share) | $ / shares	$ 17.26
Granted (in dollars per share) | $ / shares	21.81
Vested (in dollars per share) | $ / shares	17.48
Balance at the end of period (in dollars per share) | $ / shares	$ 18.76
Starwood Property Trust, Inc. Equity Plan
Non-Vested Shares and Share Equivalents activity
Balance at the beginning of the period (in shares)	1,594,605
Granted (in shares)	1,518,072
Vested (in shares)	(633,893)
Balance at the end of the period (in shares)	2,478,784
Starwood Property Trust, Inc. Manager Equity Plan
Non-Vested Shares and Share Equivalents activity
Balance at the beginning of the period (in shares)	2,286,896
Vested (in shares)	(296,342)
Balance at the end of the period (in shares)	1,990,554