Segment Data - Schedule of Consolidated Balance Sheet by Business Segment (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Assets:
Cash and cash equivalents	$ 327,363	$ 194,660
Restricted cash	125,341	117,312
Loans held-for-investment	16,606,862	17,574,249
Loans held-for-sale	2,689,368	2,645,637
Investment securities	716,073	735,562
Properties, net	1,044,565	1,046,384
Properties held-for-sale, net	0	290,937
Investments in unconsolidated entities	96,927	90,376
Goodwill	259,846	259,846
Intangible assets	63,267	64,967
Derivative assets	82,916	63,437
Accrued interest receivable	194,498	200,867
Other assets	319,853	420,773
VIE assets, at fair value	41,633,853	43,786,356
Total Assets	66,169,669	69,504,196
Liabilities:
Dividends payable	153,174	152,888
Derivative liabilities	74,647	102,467
Secured financing agreements, net	12,556,487	13,867,996
Collateralized loan obligations and single asset securitization, net	3,223,867	3,491,292
Unsecured senior notes, net	2,751,666	2,158,888
Debt related to properties held for sale	0	193,691
VIE liabilities, at fair value	40,065,423	42,175,734
Total Liabilities	59,129,488	62,481,214
Temporary Equity: Redeemable non-controlling interests	415,485	414,348
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	3,234	3,208
Additional paid-in capital	5,885,852	5,864,670
Treasury stock	(138,022)	(138,022)
Retained earnings (accumulated deficit)	507,622	505,881
Accumulated other comprehensive income	14,061	15,352
Total Starwood Property Trust, Inc. Stockholders’ Equity	6,272,747	6,251,089
Non-controlling interests in consolidated subsidiaries	351,949	357,545
Total Permanent Equity	6,624,696	6,608,634	$ 6,752,473	$ 6,835,917
Total Liabilities and Equity	66,169,669	69,504,196
Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	259,998	293,442
Related Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	44,226	44,816
Primary Beneficiary
Assets:
Investments of consolidated affordable housing fund	2,008,937	2,012,833
Total Assets	48,000
Liabilities:
Total Liabilities	10,200
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	327,363	194,660
Restricted cash	125,341	117,312
Loans held-for-investment	16,606,862	17,574,249
Loans held-for-sale	2,689,368	2,645,637
Investment securities	2,256,227	2,314,421
Properties, net	1,044,565	1,046,384
Properties held-for-sale, net		290,937
Investments in unconsolidated entities	111,543	104,976
Goodwill	259,846	259,846
Intangible assets	97,522	102,832
Derivative assets	82,916	63,437
Accrued interest receivable	194,498	200,867
Other assets	319,853	420,773
VIE assets, at fair value	0	0
Total Assets	26,124,841	27,349,164
Liabilities:
Dividends payable	153,174	152,888
Derivative liabilities	74,647	102,467
Secured financing agreements, net	12,577,137	13,888,753
Collateralized loan obligations and single asset securitization, net	3,223,867	3,491,292
Unsecured senior notes, net	2,751,666	2,158,888
Debt related to properties held for sale		193,691
VIE liabilities, at fair value	0	0
Total Liabilities	19,084,715	20,326,237
Temporary Equity: Redeemable non-controlling interests	415,485	414,348
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	3,234	3,208
Additional paid-in capital	5,885,852	5,864,670
Treasury stock	(138,022)	(138,022)
Retained earnings (accumulated deficit)	507,622	505,881
Accumulated other comprehensive income	14,061	15,352
Total Starwood Property Trust, Inc. Stockholders’ Equity	6,272,747	6,251,089
Non-controlling interests in consolidated subsidiaries	351,894	357,490
Total Permanent Equity	6,624,641	6,608,579
Total Liabilities and Equity	26,124,841	27,349,164
Subtotal | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	259,998	293,442
Subtotal | Related Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	44,226	44,816
Subtotal | Primary Beneficiary
Assets:
Investments of consolidated affordable housing fund	2,008,937	2,012,833
Operating segment | Commercial and Residential Lending Segment
Assets:
Cash and cash equivalents	9,602	8,823
Restricted cash	11,506	23,902
Loans held-for-investment	14,221,471	15,069,389
Loans held-for-sale	2,518,600	2,604,594
Investment securities	1,113,081	1,147,829
Properties, net	434,365	431,155
Properties held-for-sale, net		0
Investments in unconsolidated entities	25,371	19,151
Goodwill	0	0
Intangible assets	12,724	13,415
Derivative assets	73,830	55,559
Accrued interest receivable	179,147	180,441
Other assets	186,807	301,436
VIE assets, at fair value	0	0
Total Assets	18,786,504	19,855,694
Liabilities:
Dividends payable	0	0
Derivative liabilities	22,074	54,066
Secured financing agreements, net	9,051,746	10,368,668
Collateralized loan obligations and single asset securitization, net	2,406,928	2,674,938
Unsecured senior notes, net	0	0
Debt related to properties held for sale		0
VIE liabilities, at fair value	0	0
Total Liabilities	11,607,771	13,203,908
Temporary Equity: Redeemable non-controlling interests	0	0
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	1,486,260	1,121,413
Treasury stock	0	0
Retained earnings (accumulated deficit)	5,678,294	5,514,906
Accumulated other comprehensive income	14,061	15,352
Total Starwood Property Trust, Inc. Stockholders’ Equity	7,178,615	6,651,671
Non-controlling interests in consolidated subsidiaries	118	115
Total Permanent Equity	7,178,733	6,651,786
Total Liabilities and Equity	18,786,504	19,855,694
Operating segment | Commercial and Residential Lending Segment | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	127,023	106,236
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	137,049	56,300
Restricted cash	41,394	28,693
Loans held-for-investment	2,376,191	2,495,660
Loans held-for-sale	47,149	0
Investment securities	18,422	19,042
Properties, net	0	0
Properties held-for-sale, net		0
Investments in unconsolidated entities	53,018	52,691
Goodwill	119,409	119,409
Intangible assets	0	0
Derivative assets	216	84
Accrued interest receivable	11,750	12,485
Other assets	5,745	3,486
VIE assets, at fair value	0	0
Total Assets	2,810,343	2,787,850
Liabilities:
Dividends payable	0	0
Derivative liabilities	0	0
Secured financing agreements, net	1,069,519	1,088,965
Collateralized loan obligations and single asset securitization, net	816,939	816,354
Unsecured senior notes, net	0	0
Debt related to properties held for sale		0
VIE liabilities, at fair value	0	0
Total Liabilities	1,910,795	1,950,551
Temporary Equity: Redeemable non-controlling interests	0	0
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	705,773	664,621
Treasury stock	0	0
Retained earnings (accumulated deficit)	193,775	172,678
Accumulated other comprehensive income	0	0
Total Starwood Property Trust, Inc. Stockholders’ Equity	899,548	837,299
Non-controlling interests in consolidated subsidiaries	0	0
Total Permanent Equity	899,548	837,299
Total Liabilities and Equity	2,810,343	2,787,850
Operating segment | Infrastructure Lending Segment | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	24,337	45,232
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	29,103	19,957
Restricted cash	1,031	1,016
Loans held-for-investment	0	0
Loans held-for-sale	0	0
Investment securities	0	0
Properties, net	551,502	555,455
Properties held-for-sale, net		290,937
Investments in unconsolidated entities	0	0
Goodwill	0	0
Intangible assets	24,505	25,432
Derivative assets	4,280	5,638
Accrued interest receivable	1,484	1,502
Other assets	61,505	50,459
VIE assets, at fair value	0	0
Total Assets	2,682,347	2,963,229
Liabilities:
Dividends payable	0	0
Derivative liabilities	0	0
Secured financing agreements, net	598,850	598,350
Collateralized loan obligations and single asset securitization, net	0	0
Unsecured senior notes, net	0	0
Debt related to properties held for sale		193,691
VIE liabilities, at fair value	0	0
Total Liabilities	609,580	804,266
Temporary Equity: Redeemable non-controlling interests	415,485	414,348
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	(615,052)	(437,169)
Treasury stock	0	0
Retained earnings (accumulated deficit)	2,065,089	1,974,539
Accumulated other comprehensive income	0	0
Total Starwood Property Trust, Inc. Stockholders’ Equity	1,450,037	1,537,370
Non-controlling interests in consolidated subsidiaries	207,245	207,245
Total Permanent Equity	1,657,282	1,744,615
Total Liabilities and Equity	2,682,347	2,963,229
Operating segment | Property Segment | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	10,730	12,225
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	2,008,937	2,012,833
Operating segment | Investing and Servicing Segment
Assets:
Cash and cash equivalents	8,340	22,011
Restricted cash	6,862	5,175
Loans held-for-investment	9,200	9,200
Loans held-for-sale	123,619	41,043
Investment securities	1,124,724	1,147,550
Properties, net	58,698	59,774
Properties held-for-sale, net		0
Investments in unconsolidated entities	33,154	33,134
Goodwill	140,437	140,437
Intangible assets	60,293	63,985
Derivative assets	4,590	2,156
Accrued interest receivable	1,939	1,369
Other assets	17,296	15,828
VIE assets, at fair value	0	0
Total Assets	1,589,152	1,541,662
Liabilities:
Dividends payable	0	0
Derivative liabilities	261	0
Secured financing agreements, net	521,399	495,857
Collateralized loan obligations and single asset securitization, net	0	0
Unsecured senior notes, net	0	0
Debt related to properties held for sale		0
VIE liabilities, at fair value	0	0
Total Liabilities	550,596	540,309
Temporary Equity: Redeemable non-controlling interests	0	0
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	(663,588)	(705,176)
Treasury stock	0	0
Retained earnings (accumulated deficit)	1,557,613	1,556,399
Accumulated other comprehensive income	0	0
Total Starwood Property Trust, Inc. Stockholders’ Equity	894,025	851,223
Non-controlling interests in consolidated subsidiaries	144,531	150,130
Total Permanent Equity	1,038,556	1,001,353
Total Liabilities and Equity	1,589,152	1,541,662
Operating segment | Investing and Servicing Segment | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	28,936	44,452
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	143,269	87,569
Restricted cash	64,548	58,526
Loans held-for-investment	0	0
Loans held-for-sale	0	0
Investment securities	0	0
Properties, net	0	0
Properties held-for-sale, net		0
Investments in unconsolidated entities	0	0
Goodwill	0	0
Intangible assets	0	0
Derivative assets	0	0
Accrued interest receivable	178	5,070
Other assets	48,500	49,564
VIE assets, at fair value	0	0
Total Assets	256,495	200,729
Liabilities:
Dividends payable	153,174	152,888
Derivative liabilities	52,312	48,401
Secured financing agreements, net	1,335,623	1,336,913
Collateralized loan obligations and single asset securitization, net	0	0
Unsecured senior notes, net	2,751,666	2,158,888
Debt related to properties held for sale		0
VIE liabilities, at fair value	0	0
Total Liabilities	4,405,973	3,827,203
Temporary Equity: Redeemable non-controlling interests	0	0
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	3,234	3,208
Additional paid-in capital	4,972,459	5,220,981
Treasury stock	(138,022)	(138,022)
Retained earnings (accumulated deficit)	(8,987,149)	(8,712,641)
Accumulated other comprehensive income	0	0
Total Starwood Property Trust, Inc. Stockholders’ Equity	(4,149,478)	(3,626,474)
Non-controlling interests in consolidated subsidiaries	0	0
Total Permanent Equity	(4,149,478)	(3,626,474)
Total Liabilities and Equity	256,495	200,729
Corporate | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	68,972	85,297
Corporate | Related Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	44,226	44,816
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	(1,540,154)	(1,578,859)
Properties, net	0	0
Properties held-for-sale, net		0
Investments in unconsolidated entities	(14,616)	(14,600)
Goodwill	0	0
Intangible assets	(34,255)	(37,865)
Derivative assets	0	0
Accrued interest receivable	0	0
Other assets	0	0
VIE assets, at fair value	41,633,853	43,786,356
Total Assets	40,044,828	42,155,032
Liabilities:
Dividends payable	0	0
Derivative liabilities	0	0
Secured financing agreements, net	(20,650)	(20,757)
Collateralized loan obligations and single asset securitization, net	0	0
Unsecured senior notes, net	0	0
Debt related to properties held for sale		0
VIE liabilities, at fair value	40,065,423	42,175,734
Total Liabilities	40,044,773	42,154,977
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	55	55
Total Permanent Equity	55	55
Total Liabilities and Equity	40,044,828	42,155,032
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