Secured Borrowings - Collateralized Loan Obligations (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) Item	Dec. 31, 2022 USD ($) Item	Feb. 28, 2022 USD ($)	Jan. 31, 2022 USD ($)	May 31, 2021 USD ($)	Apr. 30, 2021 USD ($)	Aug. 31, 2019 USD ($)
Summary of CLO
Carrying Value	$ 3,491,292	$ 3,676,224
Collateral assets
Summary of CLO
Face Amount	4,226,614	4,401,641
Carrying Value	4,288,770	4,454,087
Financing
Summary of CLO
Face Amount	3,500,163	3,689,140
Carrying Value	$ 3,491,292	$ 3,676,224
STWD 2022-FL3
Summary of CLO
Face Amount			$ 1,000,000
STWD 2022-FL3 | Collateral assets
Summary of CLO
Count | Item	48	51
Face Amount	$ 997,569	$ 1,000,000
Carrying Value	$ 1,007,532	$ 1,010,051
STWD 2022-FL3 | Financing
Summary of CLO
Count | Item	1	1
Face Amount	$ 840,620	$ 842,500
Carrying Value	$ 837,881	$ 842,374
STWD 2022-FL3 | SOFR | Collateral assets
Summary of CLO
Weighted Average Spread	3.53%
STWD 2022-FL3 | SOFR | Financing
Summary of CLO
Weighted Average Spread	1.89%	1.93%
STWD 2022-FL3 | Index | Collateral assets
Summary of CLO
Weighted Average Spread		3.52%
STWD 2021-HTS | Collateral assets
Summary of CLO
Count | Item	1	1
Face Amount	$ 223,193	$ 230,000
Carrying Value	$ 224,509	$ 231,186
STWD 2021-HTS | Financing
Summary of CLO
Count | Item	1	1
Face Amount	$ 203,284	$ 210,091
Carrying Value	$ 203,058	$ 208,961
STWD 2021-HTS | SOFR | Collateral assets
Summary of CLO
Weighted Average Spread	3.87%
STWD 2021-HTS | SOFR | Financing
Summary of CLO
Weighted Average Spread	2.82%
STWD 2021-HTS | LIBOR | Collateral assets
Summary of CLO
Weighted Average Spread		3.85%
STWD 2021-HTS | LIBOR | Financing
Summary of CLO
Weighted Average Spread		2.71%
STWD 2021-FL2
Summary of CLO
Face Amount					$ 1,300,000
Percent of outstanding loan	7.00%
Debt, weighted average interest rate	7.39%
STWD 2021-FL2 | Collateral assets
Summary of CLO
Count | Item	34	36
Face Amount	$ 1,272,585	$ 1,277,474
Carrying Value	$ 1,288,165	$ 1,284,240
STWD 2021-FL2 | Financing
Summary of CLO
Count | Item	1	1
Face Amount	$ 1,065,713	$ 1,077,375
Carrying Value	$ 1,063,454	$ 1,072,403
STWD 2021-FL2 | SOFR | Collateral assets
Summary of CLO
Weighted Average Spread	3.95%
STWD 2021-FL2 | SOFR | Financing
Summary of CLO
Weighted Average Spread	1.85%
STWD 2021-FL2 | Index | Collateral assets
Summary of CLO
Weighted Average Spread		4.04%
STWD 2021-FL2 | LIBOR | Financing
Summary of CLO
Weighted Average Spread		1.80%
STWD 2019-FL1
Summary of CLO
Face Amount							$ 1,100,000
STWD 2019-FL1 | Collateral assets
Summary of CLO
Count | Item	14	16
Face Amount	$ 734,099	$ 902,799
Carrying Value	$ 739,684	$ 906,409
STWD 2019-FL1 | Financing
Summary of CLO
Count | Item	1	1
Face Amount	$ 570,546	$ 739,174
Carrying Value	$ 570,546	$ 738,473
STWD 2019-FL1 | SOFR | Collateral assets
Summary of CLO
Weighted Average Spread	3.51%
STWD 2019-FL1 | SOFR | Financing
Summary of CLO
Weighted Average Spread	1.62%	1.64%
STWD 2019-FL1 | Index | Collateral assets
Summary of CLO
Weighted Average Spread		3.67%
STWD 2021-SIF2
Summary of CLO
Face Amount				$ 500,000
STWD 2021-SIF2 | Collateral assets
Summary of CLO
Count | Item	30	31
Face Amount	$ 499,401	$ 495,587
Carrying Value	$ 514,286	$ 510,730
STWD 2021-SIF2 | Financing
Summary of CLO
Count | Item	1	1
Face Amount	$ 410,000	$ 410,000
Carrying Value	$ 408,166	$ 407,260
STWD 2021-SIF2 | SOFR | Collateral assets
Summary of CLO
Weighted Average Spread	3.87%
STWD 2021-SIF2 | SOFR | Financing
Summary of CLO
Weighted Average Spread	2.11%	2.11%
STWD 2021-SIF2 | Index | Collateral assets
Summary of CLO
Weighted Average Spread		3.73%
STWD 2021-SIF1
Summary of CLO
Face Amount						$ 500,000
Percent of outstanding loan	2.00%
Debt, weighted average interest rate	5.70%
STWD 2021-SIF1 | Collateral assets
Summary of CLO
Count | Item	32	31
Face Amount	$ 499,767	$ 495,781
Carrying Value	$ 514,594	$ 511,471
STWD 2021-SIF1 | Financing
Summary of CLO
Count | Item	1	1
Face Amount	$ 410,000	$ 410,000
Carrying Value	$ 408,187	$ 406,753
STWD 2021-SIF1 | SOFR | Collateral assets
Summary of CLO
Weighted Average Spread	3.97%
STWD 2021-SIF1 | SOFR | Financing
Summary of CLO
Weighted Average Spread	2.42%
STWD 2021-SIF1 | Index | Collateral assets
Summary of CLO
Weighted Average Spread		3.76%
STWD 2021-SIF1 | LIBOR | Financing
Summary of CLO
Weighted Average Spread		2.15%