Segment Data - Schedule of Results of Operations by Business Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenues:
Interest income from loans	$ 463,492	$ 430,908
Interest income from investment securities	18,206	18,637
Servicing fees	9,689	7,256
Rental income	28,847	32,289
Other revenues	2,854	1,324
Total revenues	523,088	490,414
Costs and expenses:
Management fees	46,014	39,540
Interest expense	355,956	335,301
General and administrative	50,663	42,108
Costs of rental operations	10,344	11,666
Depreciation and amortization	9,818	12,416
Credit loss provision, net	35,839	43,194
Other expense	674	1,117
Total costs and expenses	509,308	485,342
Other income (loss):
Change in net assets related to consolidated VIEs	10,086	41,138
Change in fair value of servicing rights	228	304
Change in fair value of investment securities, net	915	82
Change in fair value of mortgage loans, net	(29,013)	8,901
Earnings (loss) from unconsolidated entities	7,675	2,725
(Loss) gain on sale of investments and other assets, net	91,962	190
Gain (loss) on derivative financial instruments, net	101,939	(32,828)
Foreign currency (loss) gain, net	(41,870)	15,019
Gain (loss) on extinguishment of debt	(1,454)	(61)
Other (loss) income, net	(2,630)	(2,541)
Total other income (loss)	147,286	45,894
Income (loss) before income taxes	161,066	50,966
Income tax (provision) benefit	(1,206)	8,795
Net income (loss)	159,860	59,761
Net (income) loss attributable to non-controlling interests	(5,528)	(7,787)
Net income (loss) attributable to Starwood Property Trust, Inc.	154,332	51,974
Primary Beneficiary
Other income (loss):
Income from affordable housing fund investments	9,448	12,965
Subtotal
Revenues:
Interest income from loans	463,492	430,908
Interest income from investment securities	52,687	56,644
Servicing fees	13,167	9,993
Rental income	28,847	32,289
Other revenues	2,854	1,324
Total revenues	561,047	531,158
Costs and expenses:
Management fees	46,014	39,540
Interest expense	356,166	335,511
General and administrative	50,663	42,108
Costs of rental operations	10,344	11,666
Depreciation and amortization	9,818	12,416
Credit loss provision, net	35,839	43,194
Other expense	674	1,117
Total costs and expenses	509,518	485,552
Other income (loss):
Change in net assets related to consolidated VIEs	0	0
Change in fair value of servicing rights	(3,381)	(50)
Change in fair value of investment securities, net	(23,449)	407
Change in fair value of mortgage loans, net	(29,013)	8,901
Earnings (loss) from unconsolidated entities	7,985	3,358
(Loss) gain on sale of investments and other assets, net	91,962	190
Gain (loss) on derivative financial instruments, net	101,939	(32,828)
Foreign currency (loss) gain, net	(41,870)	15,019
Gain (loss) on extinguishment of debt	(1,454)	(61)
Other (loss) income, net	(2,630)	(2,541)
Total other income (loss)	109,537	5,360
Income (loss) before income taxes	161,066	50,966
Income tax (provision) benefit	(1,206)	8,795
Net income (loss)	159,860	59,761
Net (income) loss attributable to non-controlling interests	(5,528)	(7,787)
Net income (loss) attributable to Starwood Property Trust, Inc.	154,332	51,974
Subtotal | Primary Beneficiary
Other income (loss):
Income from affordable housing fund investments	9,448	12,965
Operating segment | Commercial and Residential Lending Segment
Revenues:
Interest income from loans	394,472	375,601
Interest income from investment securities	31,405	32,521
Servicing fees	128	159
Rental income	3,565	1,981
Other revenues	983	344
Total revenues	430,553	410,606
Costs and expenses:
Management fees	192	218
Interest expense	236,149	226,393
General and administrative	16,828	11,893
Costs of rental operations	2,025	2,451
Depreciation and amortization	1,949	1,631
Credit loss provision, net	34,977	30,790
Other expense	730	1,039
Total costs and expenses	292,850	274,415
Other income (loss):
Change in net assets related to consolidated VIEs	0	0
Change in fair value of servicing rights	0	0
Change in fair value of investment securities, net	(6,991)	14,866
Change in fair value of mortgage loans, net	(40,677)	8,262
Earnings (loss) from unconsolidated entities	7,345	939
(Loss) gain on sale of investments and other assets, net	(41)	0
Gain (loss) on derivative financial instruments, net	110,952	(34,363)
Foreign currency (loss) gain, net	(41,818)	14,930
Gain (loss) on extinguishment of debt	315	(61)
Other (loss) income, net	(2,676)	(2,541)
Total other income (loss)	26,409	2,032
Income (loss) before income taxes	164,112	138,223
Income tax (provision) benefit	(721)	6,557
Net income (loss)	163,391	144,780
Net (income) loss attributable to non-controlling interests	(3)	(3)
Net income (loss) attributable to Starwood Property Trust, Inc.	163,388	144,777
Operating segment | Commercial and Residential Lending Segment | Primary Beneficiary
Other income (loss):
Income from affordable housing fund investments	0	0
Operating segment | Infrastructure Lending Segment
Revenues:
Interest income from loans	66,398	54,760
Interest income from investment securities	138	1,338
Servicing fees	0	0
Rental income	0	0
Other revenues	392	216
Total revenues	66,928	56,314
Costs and expenses:
Management fees	0	0
Interest expense	38,973	32,818
General and administrative	5,955	3,964
Costs of rental operations	0	0
Depreciation and amortization	14	30
Credit loss provision, net	862	12,404
Other expense	0	8
Total costs and expenses	45,804	49,224
Other income (loss):
Change in net assets related to consolidated VIEs	0	0
Change in fair value of servicing rights	0	0
Change in fair value of investment securities, net	0	0
Change in fair value of mortgage loans, net	0	0
Earnings (loss) from unconsolidated entities	327	1,740
(Loss) gain on sale of investments and other assets, net	0	0
Gain (loss) on derivative financial instruments, net	122	(51)
Foreign currency (loss) gain, net	(84)	75
Gain (loss) on extinguishment of debt	(560)	0
Other (loss) income, net	40	0
Total other income (loss)	(155)	1,764
Income (loss) before income taxes	20,969	8,854
Income tax (provision) benefit	128	46
Net income (loss)	21,097	8,900
Net (income) loss attributable to non-controlling interests	0	0
Net income (loss) attributable to Starwood Property Trust, Inc.	21,097	8,900
Operating segment | Infrastructure Lending Segment | Primary Beneficiary
Other income (loss):
Income from affordable housing fund investments	0	0
Operating segment | Property Segment
Revenues:
Interest income from loans	0	0
Interest income from investment securities	0	0
Servicing fees	0	0
Rental income	20,775	23,695
Other revenues	127	103
Total revenues	20,902	23,798
Costs and expenses:
Management fees	0	0
Interest expense	13,298	12,599
General and administrative	1,263	952
Costs of rental operations	5,707	5,549
Depreciation and amortization	5,855	8,108
Credit loss provision, net	0	0
Other expense	0	0
Total costs and expenses	26,123	27,208
Other income (loss):
Change in net assets related to consolidated VIEs	0	0
Change in fair value of servicing rights	0	0
Change in fair value of investment securities, net	0	0
Change in fair value of mortgage loans, net	0	0
Earnings (loss) from unconsolidated entities	0	0
(Loss) gain on sale of investments and other assets, net	92,003	0
Gain (loss) on derivative financial instruments, net	1,721	(1,217)
Foreign currency (loss) gain, net	32	14
Gain (loss) on extinguishment of debt	(1,209)	0
Other (loss) income, net	0	0
Total other income (loss)	101,995	11,762
Income (loss) before income taxes	96,774	8,352
Income tax (provision) benefit	0	0
Net income (loss)	96,774	8,352
Net (income) loss attributable to non-controlling interests	(6,225)	(6,978)
Net income (loss) attributable to Starwood Property Trust, Inc.	90,549	1,374
Operating segment | Property Segment | Primary Beneficiary
Other income (loss):
Income from affordable housing fund investments	9,448	12,965
Operating segment | Investing and Servicing Segment
Revenues:
Interest income from loans	2,622	547
Interest income from investment securities	21,144	22,785
Servicing fees	13,039	9,834
Rental income	4,507	6,613
Other revenues	748	383
Total revenues	42,060	40,162
Costs and expenses:
Management fees	0	0
Interest expense	8,317	7,429
General and administrative	23,467	20,047
Costs of rental operations	2,612	3,666
Depreciation and amortization	1,749	2,647
Credit loss provision, net	0	0
Other expense	(56)	70
Total costs and expenses	36,089	33,859
Other income (loss):
Change in net assets related to consolidated VIEs	0	0
Change in fair value of servicing rights	(3,381)	(50)
Change in fair value of investment securities, net	(16,458)	(14,459)
Change in fair value of mortgage loans, net	11,664	639
Earnings (loss) from unconsolidated entities	313	679
(Loss) gain on sale of investments and other assets, net	0	190
Gain (loss) on derivative financial instruments, net	3,012	(3,467)
Foreign currency (loss) gain, net	0	0
Gain (loss) on extinguishment of debt	0	0
Other (loss) income, net	6	0
Total other income (loss)	(4,844)	(16,468)
Income (loss) before income taxes	1,127	(10,165)
Income tax (provision) benefit	(613)	2,192
Net income (loss)	514	(7,973)
Net (income) loss attributable to non-controlling interests	700	(806)
Net income (loss) attributable to Starwood Property Trust, Inc.	1,214	(8,779)
Operating segment | Investing and Servicing Segment | Primary Beneficiary
Other income (loss):
Income from affordable housing fund investments	0	0
Corporate
Revenues:
Interest income from loans	0	0
Interest income from investment securities	0	0
Servicing fees	0	0
Rental income	0	0
Other revenues	604	278
Total revenues	604	278
Costs and expenses:
Management fees	45,822	39,322
Interest expense	59,429	56,272
General and administrative	3,150	5,252
Costs of rental operations	0	0
Depreciation and amortization	251	0
Credit loss provision, net	0	0
Other expense	0	0
Total costs and expenses	108,652	100,846
Other income (loss):
Change in net assets related to consolidated VIEs	0	0
Change in fair value of servicing rights	0	0
Change in fair value of investment securities, net	0	0
Change in fair value of mortgage loans, net	0	0
Earnings (loss) from unconsolidated entities	0	0
(Loss) gain on sale of investments and other assets, net	0	0
Gain (loss) on derivative financial instruments, net	(13,868)	6,270
Foreign currency (loss) gain, net	0	0
Gain (loss) on extinguishment of debt	0	0
Other (loss) income, net	0	0
Total other income (loss)	(13,868)	6,270
Income (loss) before income taxes	(121,916)	(94,298)
Income tax (provision) benefit	0	0
Net income (loss)	(121,916)	(94,298)
Net (income) loss attributable to non-controlling interests	0	0
Net income (loss) attributable to Starwood Property Trust, Inc.	(121,916)	(94,298)
Corporate | Primary Beneficiary
Other income (loss):
Income from affordable housing fund investments	0	0
Securitization VIEs
Revenues:
Interest income from loans	0	0
Interest income from investment securities	(34,481)	(38,007)
Servicing fees	(3,478)	(2,737)
Rental income	0	0
Other revenues	0	0
Total revenues	(37,959)	(40,744)
Costs and expenses:
Management fees	0	0
Interest expense	(210)	(210)
General and administrative	0	0
Costs of rental operations	0	0
Depreciation and amortization	0	0
Credit loss provision, net	0	0
Other expense	0	0
Total costs and expenses	(210)	(210)
Other income (loss):
Change in net assets related to consolidated VIEs	10,086	41,138
Change in fair value of servicing rights	3,609	354
Change in fair value of investment securities, net	24,364	(325)
Change in fair value of mortgage loans, net	0	0
Earnings (loss) from unconsolidated entities	(310)	(633)
(Loss) gain on sale of investments and other assets, net	0	0
Gain (loss) on derivative financial instruments, net	0	0
Foreign currency (loss) gain, net	0	0
Gain (loss) on extinguishment of debt	0	0
Other (loss) income, net	0	0
Total other income (loss)	37,749	40,534
Income (loss) before income taxes	0	0
Income tax (provision) benefit	0	0
Net income (loss)	0	0
Net (income) loss attributable to non-controlling interests	0	0
Net income (loss) attributable to Starwood Property Trust, Inc.	0	0
Securitization VIEs | Primary Beneficiary
Other income (loss):
Income from affordable housing fund investments	$ 0	$ 0