Secured Borrowings - Narrative (Details) $ in Thousands	1 Months Ended				3 Months Ended
	Feb. 28, 2022 USD ($)	Jan. 31, 2022 USD ($)	Jul. 31, 2021 USD ($) hotel	Apr. 30, 2021 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	May 31, 2021 USD ($)	Aug. 31, 2019 USD ($)
Secured Borrowings
Principal amount of notes purchased by third-party investors			$ 210,100
RMBS
Secured Borrowings
Securitizations of loans			$ 230,000
Number of hotels | hotel			41
STWD 2022-FL3
Secured Borrowings
Face amount	$ 1,000,000
Principal amount of notes purchased by third-party investors	842,500
Long term debt, gross	82,500
Liquidation preference	$ 75,000
CLO contribution period	2 years
Additional contribution to CLO					$ 6,700
STWD 2021-FL2
Secured Borrowings
Face amount								$ 1,300,000
Principal amount of notes purchased by third-party investors								1,100,000
Long term debt, gross								70,100
Liquidation preference								$ 127,500
Repayments of debt					73,500
STWD 2019-FL1
Secured Borrowings
Face amount									$ 1,100,000
Principal amount of notes purchased by third-party investors									936,400
Long term debt, gross									86,600
Liquidation preference									$ 77,000
Repayments of debt					184,200
STWD 2021-SIF2
Secured Borrowings
Face amount		$ 500,000
Principal amount of notes purchased by third-party investors		410,000
Liquidation preference		$ 90,000
CLO contribution period		3 years
Additional contribution to CLO					17,800
STWD 2021-SIF1
Secured Borrowings
Face amount				$ 500,000
Principal amount of notes purchased by third-party investors				410,000
Liquidation preference				$ 90,000
CLO contribution period				3 years
Additional contribution to CLO					27,200
CLOs and SASB
Secured Borrowings
Amortization of deferred financing costs					2,000	$ 2,700
Incurred debt issuance costs					37,900
Deferred financing costs, net of amortization					7,500		$ 9,500
Morgan Stanley Bank, N.A.
Secured Borrowings
Amount at risk					$ 918,200
Weighted average extended maturities					3 years 4 months 24 days
Wells Fargo Bank, N.A.
Secured Borrowings
Amount at risk					$ 818,300
Weighted average extended maturities					6 years 6 months
JPMorgan Chase Bank N.A.
Secured Borrowings
Amount at risk					$ 671,100
Weighted average extended maturities					3 years 8 months 12 days
Repurchase Agreements
Secured Borrowings
Percentage of repurchase agreements for which margin calls are limited to collateral specific credit marks					65.00%
Percentage of repurchase agreements containing margin call provisions for general capital market activity					35.00%
Percentage of repurchase agreements containing margin call provisions that pertain to loans held-for-sale					6.00%
Secured Borrowings
Secured Borrowings
Amortization of deferred financing costs					$ 9,600	$ 10,200
Long term debt, gross					$ 12,625,490		$ 13,948,828