Stockholders' Equity and Non-Controlling Interests - Narrative (Details) $ in Thousands			3 Months Ended		12 Months Ended
	Nov. 06, 2021 USD ($)	Nov. 05, 2021 USD ($)	Mar. 31, 2022 USD ($) extension shares	Mar. 31, 2021 USD ($) shares	Dec. 31, 2021 USD ($)	Dec. 31, 2018 shares	May 31, 2017 shares
Equity Incentive Plans
Shares issued ATM (in shares) | shares			0	0
Contributions from non-controlling interests			$ 4,690	$ 2,969
Net income			47,720
Net income attributable to non-controlling interests			$ 59,715	11,148
Woodstar Fund
Equity Incentive Plans
Percentage of interest sold		20.60%
Contributions from non-controlling interests	$ 214,200	$ 216,000
Initial term			8 years
Number of extension options | extension			2
Extension term			1 year
CMBS JV
Equity Incentive Plans
Non-controlling interest			$ 140,100		$ 131,900
CMBS JV | Joint Venture Partner
Equity Incentive Plans
Ownership percentage			49.00%
CMBS JV
Equity Incentive Plans
Ownership percentage			51.00%
Class A Units
Equity Incentive Plans
Number of units outstanding (in shares) | shares			9,800,000
Woodstar II Portfolio | Class A Units
Equity Incentive Plans
Net income attributable to non-controlling interests			$ 4,700	5,100
Woodstar II Portfolio | Class A Units | CMBS JV
Equity Incentive Plans
Net income attributable to non-controlling interests			$ 3,600	$ 5,400
Subsidiaries | Woodstar II Portfolio | Class A Units
Equity Incentive Plans
Shares issued (in shares) | shares						10,200,000
Right to receive additional shares (in shares) | shares			1,900,000			1,900,000
Subsidiaries | Woodstar II Portfolio | Class A Units | Non- Controlling Interests
Equity Incentive Plans
Redemption of units			$ 208,500		$ 208,500
Starwood Property Trust, Inc. Equity Plan and Manager Equity Plan
Equity Incentive Plans
Number of shares of authorized for issuance (in shares) | shares							11,000,000
Number of shares available for future grants (in shares) | shares			2,400,000