Segment Data - Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2023
Assets:
Cash and cash equivalents	$ 440,580	$ 377,831
Restricted cash	251,771	176,164
Loans held-for-investment	16,521,979	15,437,013
Loans held-for-sale	2,446,636	2,516,008
Investment securities	497,459	533,258
Properties, net	1,413,234	1,373,678
Investments in unconsolidated entities	98,462	99,370
Goodwill	259,846	259,846
Intangible assets	59,797	60,704
Derivative assets	84,972	175,520
Accrued interest receivable	142,691	167,767
Other assets	409,804	368,229
VIE assets, at fair value	37,470,618	38,937,576
Total Assets	62,163,347	62,556,497
Liabilities:
Dividends payable	165,039	163,383
Derivative liabilities	72,975	94,890
Secured financing agreements, net	12,438,438	11,151,557
Collateralized loan obligations and single asset securitization, net	3,165,296	3,196,426
Unsecured senior notes, net	2,747,330	2,994,682
VIE liabilities, at fair value	35,901,085	37,288,545
Total Liabilities	55,006,596	55,363,025
Temporary Equity: Redeemable non-controlling interests	426,835	426,695
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	3,468	3,449
Additional paid-in capital	6,343,893	6,322,763
Treasury stock	(138,022)	(138,022)
Retained earnings (accumulated deficit)	183,599	235,323
Accumulated other comprehensive income	12,727	13,594
Total Starwood Property Trust, Inc. Stockholders’ Equity	6,405,665	6,437,107
Non-controlling interests in consolidated subsidiaries	324,251	329,670
Total Permanent Equity	6,729,916	6,766,777	$ 6,624,696	$ 6,608,634
Total Liabilities and Equity	62,163,347	62,556,497
Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	479,895	434,584
Related Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	36,538	38,958
Primary Beneficiary
Assets:
Investments of consolidated affordable housing fund	2,065,498	2,073,533
Total Assets	63,800
Liabilities:
Total Liabilities	100
Infrastructure Lending Segment
Assets:
Goodwill	119,400	119,400
Investing and Servicing Segment
Assets:
Goodwill	140,400	140,400
Subtotal
Assets:
Cash and cash equivalents	440,580	377,831
Restricted cash	251,771	176,164
Loans held-for-investment	16,521,979	15,437,013
Loans held-for-sale	2,446,636	2,516,008
Investment securities	2,037,435	2,152,059
Properties, net	1,413,234	1,373,678
Investments in unconsolidated entities	113,360	114,186
Goodwill	259,846	259,846
Intangible assets	94,675	96,449
Derivative assets	84,972	175,520
Accrued interest receivable	142,691	167,767
Other assets	409,804	368,229
VIE assets, at fair value	0	0
Total Assets	26,282,481	25,288,283
Liabilities:
Dividends payable	165,039	163,383
Derivative liabilities	72,975	94,890
Secured financing agreements, net	12,458,657	11,171,888
Collateralized loan obligations and single asset securitization, net	3,165,296	3,196,426
Unsecured senior notes, net	2,747,330	2,994,682
VIE liabilities, at fair value	0	0
Total Liabilities	19,125,730	18,094,811
Temporary Equity: Redeemable non-controlling interests	426,835	426,695
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	3,468	3,449
Additional paid-in capital	6,343,893	6,322,763
Treasury stock	(138,022)	(138,022)
Retained earnings (accumulated deficit)	183,599	235,323
Accumulated other comprehensive income	12,727	13,594
Total Starwood Property Trust, Inc. Stockholders’ Equity	6,405,665	6,437,107
Non-controlling interests in consolidated subsidiaries	324,251	329,670
Total Permanent Equity	6,729,916	6,766,777
Total Liabilities and Equity	26,282,481	25,288,283
Subtotal | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	479,895	434,584
Subtotal | Related Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	36,538	38,958
Subtotal | Primary Beneficiary
Assets:
Investments of consolidated affordable housing fund	2,065,498	2,073,533
Operating segment | Commercial and Residential Lending Segment
Assets:
Cash and cash equivalents	19,249	19,743
Restricted cash	96,106	147,502
Loans held-for-investment	13,813,048	12,895,064
Loans held-for-sale	2,375,642	2,394,624
Investment securities	871,299	909,762
Properties, net	695,579	650,966
Investments in unconsolidated entities	26,612	26,441
Goodwill	0	0
Intangible assets	9,914	10,637
Derivative assets	82,602	174,507
Accrued interest receivable	128,296	150,474
Other assets	213,713	206,103
VIE assets, at fair value	0	0
Total Assets	18,332,060	17,585,823
Liabilities:
Dividends payable	0	0
Derivative liabilities	52,248	67,452
Secured financing agreements, net	8,942,642	7,912,536
Collateralized loan obligations and single asset securitization, net	1,935,109	1,966,865
Unsecured senior notes, net	0	0
VIE liabilities, at fair value	0	0
Total Liabilities	11,227,369	10,132,156
Temporary Equity: Redeemable non-controlling interests	0	0
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	834,079	1,363,238
Treasury stock	0	0
Retained earnings (accumulated deficit)	6,257,767	6,076,720
Accumulated other comprehensive income	12,727	13,594
Total Starwood Property Trust, Inc. Stockholders’ Equity	7,104,573	7,453,552
Non-controlling interests in consolidated subsidiaries	118	115
Total Permanent Equity	7,104,691	7,453,667
Total Liabilities and Equity	18,332,060	17,585,823
Operating segment | Commercial and Residential Lending Segment | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	297,370	185,303
Operating segment | Commercial and Residential Lending Segment | Related Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	0	0
Operating segment | Commercial and Residential Lending Segment | Primary Beneficiary
Assets:
Investments of consolidated affordable housing fund	0	0
Operating segment | Infrastructure Lending Segment
Assets:
Cash and cash equivalents	161,387	122,134
Restricted cash	19,306	21,986
Loans held-for-investment	2,708,931	2,541,949
Loans held-for-sale	0	0
Investment securities	17,158	17,273
Properties, net	0	0
Investments in unconsolidated entities	53,483	54,105
Goodwill	119,409	119,409
Intangible assets	0	0
Derivative assets	0	0
Accrued interest receivable	14,029	13,961
Other assets	3,478	8,190
VIE assets, at fair value	0	0
Total Assets	3,097,181	2,899,007
Liabilities:
Dividends payable	0	0
Derivative liabilities	0	0
Secured financing agreements, net	961,524	760,299
Collateralized loan obligations and single asset securitization, net	1,230,187	1,229,561
Unsecured senior notes, net	0	0
VIE liabilities, at fair value	0	0
Total Liabilities	2,227,897	2,020,017
Temporary Equity: Redeemable non-controlling interests	0	0
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	591,500	619,428
Treasury stock	0	0
Retained earnings (accumulated deficit)	277,784	259,562
Accumulated other comprehensive income	0	0
Total Starwood Property Trust, Inc. Stockholders’ Equity	869,284	878,990
Non-controlling interests in consolidated subsidiaries	0	0
Total Permanent Equity	869,284	878,990
Total Liabilities and Equity	3,097,181	2,899,007
Operating segment | Infrastructure Lending Segment | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	36,186	30,157
Operating segment | Infrastructure Lending Segment | Related Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	0	0
Operating segment | Infrastructure Lending Segment | Primary Beneficiary
Assets:
Investments of consolidated affordable housing fund	0	0
Operating segment | Property Segment
Assets:
Cash and cash equivalents	32,113	24,717
Restricted cash	1,158	1,133
Loans held-for-investment	0	0
Loans held-for-sale	0	0
Investment securities	0	0
Properties, net	652,965	657,246
Investments in unconsolidated entities	0	0
Goodwill	0	0
Intangible assets	21,438	22,101
Derivative assets	17	115
Accrued interest receivable	0	0
Other assets	54,472	52,243
VIE assets, at fair value	0	0
Total Assets	2,827,661	2,831,088
Liabilities:
Dividends payable	0	0
Derivative liabilities	0	0
Secured financing agreements, net	480,322	479,732
Collateralized loan obligations and single asset securitization, net	0	0
Unsecured senior notes, net	0	0
VIE liabilities, at fair value	0	0
Total Liabilities	494,288	492,964
Temporary Equity: Redeemable non-controlling interests	426,835	426,695
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	(395,292)	(398,205)
Treasury stock	0	0
Retained earnings (accumulated deficit)	2,094,585	2,102,389
Accumulated other comprehensive income	0	0
Total Starwood Property Trust, Inc. Stockholders’ Equity	1,699,293	1,704,184
Non-controlling interests in consolidated subsidiaries	207,245	207,245
Total Permanent Equity	1,906,538	1,911,429
Total Liabilities and Equity	2,827,661	2,831,088
Operating segment | Property Segment | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	13,966	13,232
Operating segment | Property Segment | Related Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	0	0
Operating segment | Property Segment | Primary Beneficiary
Assets:
Investments of consolidated affordable housing fund	2,065,498	2,073,533
Operating segment | Investing and Servicing Segment
Assets:
Cash and cash equivalents	22,109	11,946
Restricted cash	349	5,543
Loans held-for-investment	0	0
Loans held-for-sale	70,994	121,384
Investment securities	1,148,978	1,225,024
Properties, net	64,690	65,466
Investments in unconsolidated entities	33,265	33,640
Goodwill	140,437	140,437
Intangible assets	63,323	63,711
Derivative assets	4	898
Accrued interest receivable	338	684
Other assets	9,033	8,700
VIE assets, at fair value	0	0
Total Assets	1,553,520	1,677,433
Liabilities:
Dividends payable	0	0
Derivative liabilities	0	0
Secured financing agreements, net	527,359	591,094
Collateralized loan obligations and single asset securitization, net	0	0
Unsecured senior notes, net	0	0
VIE liabilities, at fair value	0	0
Total Liabilities	556,754	648,718
Temporary Equity: Redeemable non-controlling interests	0	0
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	(746,610)	(706,746)
Treasury stock	0	0
Retained earnings (accumulated deficit)	1,626,488	1,613,151
Accumulated other comprehensive income	0	0
Total Starwood Property Trust, Inc. Stockholders’ Equity	879,878	906,405
Non-controlling interests in consolidated subsidiaries	116,888	122,310
Total Permanent Equity	996,766	1,028,715
Total Liabilities and Equity	1,553,520	1,677,433
Operating segment | Investing and Servicing Segment | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	29,395	57,624
Operating segment | Investing and Servicing Segment | Related Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	0	0
Operating segment | Investing and Servicing Segment | Primary Beneficiary
Assets:
Investments of consolidated affordable housing fund	0	0
Corporate
Assets:
Cash and cash equivalents	205,722	199,291
Restricted cash	134,852	0
Loans held-for-investment	0	0
Loans held-for-sale	0	0
Investment securities	0	0
Properties, net	0	0
Investments in unconsolidated entities	0	0
Goodwill	0	0
Intangible assets	0	0
Derivative assets	2,349	0
Accrued interest receivable	28	2,648
Other assets	129,108	92,993
VIE assets, at fair value	0	0
Total Assets	472,059	294,932
Liabilities:
Dividends payable	165,039	163,383
Derivative liabilities	20,727	27,438
Secured financing agreements, net	1,546,810	1,428,227
Collateralized loan obligations and single asset securitization, net	0	0
Unsecured senior notes, net	2,747,330	2,994,682
VIE liabilities, at fair value	0	0
Total Liabilities	4,619,422	4,800,956
Temporary Equity: Redeemable non-controlling interests	0	0
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	3,468	3,449
Additional paid-in capital	6,060,216	5,445,048
Treasury stock	(138,022)	(138,022)
Retained earnings (accumulated deficit)	(10,073,025)	(9,816,499)
Accumulated other comprehensive income	0	0
Total Starwood Property Trust, Inc. Stockholders’ Equity	(4,147,363)	(4,506,024)
Non-controlling interests in consolidated subsidiaries	0	0
Total Permanent Equity	(4,147,363)	(4,506,024)
Total Liabilities and Equity	472,059	294,932
Corporate | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	102,978	148,268
Corporate | Related Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	36,538	38,958
Corporate | Primary Beneficiary
Assets:
Investments of consolidated affordable housing fund	0	0
Securitization VIEs
Assets:
Cash and cash equivalents	0	0
Restricted cash	0	0
Loans held-for-investment	0	0
Loans held-for-sale	0	0
Investment securities	(1,539,976)	(1,618,801)
Properties, net	0	0
Investments in unconsolidated entities	(14,898)	(14,816)
Goodwill	0	0
Intangible assets	(34,878)	(35,745)
Derivative assets	0	0
Accrued interest receivable	0	0
Other assets	0	0
VIE assets, at fair value	37,470,618	38,937,576
Total Assets	35,880,866	37,268,214
Liabilities:
Dividends payable	0	0
Derivative liabilities	0	0
Secured financing agreements, net	(20,219)	(20,331)
Collateralized loan obligations and single asset securitization, net	0	0
Unsecured senior notes, net	0	0
VIE liabilities, at fair value	35,901,085	37,288,545
Total Liabilities	35,880,866	37,268,214
Temporary Equity: Redeemable non-controlling interests	0	0
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	0	0
Treasury stock	0	0
Retained earnings (accumulated deficit)	0	0
Accumulated other comprehensive income	0	0
Total Starwood Property Trust, Inc. Stockholders’ Equity	0	0
Non-controlling interests in consolidated subsidiaries	0	0
Total Permanent Equity	0	0
Total Liabilities and Equity	35,880,866	37,268,214
Securitization VIEs | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	0	0
Securitization VIEs | Related Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	0	0
Securitization VIEs | Primary Beneficiary
Assets:
Investments of consolidated affordable housing fund	$ 0	$ 0