Segment and Geographic Data - Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Assets:
Cash and cash equivalents	$ 194,660	$ 261,061
Restricted cash	117,312	121,072
Loans held-for-investment, net	17,574,249	18,401,439
Loans held-for-sale	2,645,637	2,784,594
Investment securities	735,562	815,804
Properties, net	1,046,384	1,449,986
Properties held-for-sale	290,937	0
Investments of consolidated affordable housing fund		1,761,002
Investments in unconsolidated entities	90,376	91,892
Goodwill	259,846	259,846
Intangible assets	64,967	68,773	$ 63,564
Derivative assets	63,437	108,621
Accrued interest receivable	200,867	168,521
Other assets	420,773	297,477
VIE assets, at fair value	43,786,356	52,453,041
Total Assets	69,504,196	79,043,129
Liabilities:
Dividends payable	152,888	151,511
Derivative liabilities	102,467	91,404
Secured financing agreements, net	13,867,996	14,501,532
Collateralized loan obligations and single asset securitization, net	3,491,292	3,676,224
Unsecured senior notes, net	2,158,888	2,329,211
Debt related to properties held-for-sale	193,691	0
VIE liabilities, at fair value	42,175,734	50,754,355
Total Liabilities	62,481,214	71,844,422
Temporary Equity: Redeemable non-controlling interests	414,348	362,790
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	3,208	3,181
Additional paid-in capital	5,864,670	5,807,087
Treasury stock	(138,022)	(138,022)
Retained earnings (accumulated deficit)	505,881	769,237
Accumulated other comprehensive income	15,352	20,955
Total Starwood Property Trust, Inc. Stockholders’ Equity	6,251,089	6,462,438
Non-controlling interests in consolidated subsidiaries	357,545	373,479
Total Permanent Equity	6,608,634	6,835,917	$ 6,433,892	$ 4,862,576
Total Liabilities and Equity	69,504,196	79,043,129
Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	293,442	298,999
Related Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	44,816	41,186
Primary beneficiary
Assets:
Investments of consolidated affordable housing fund	2,012,833	1,761,002
Total Assets	47,800
Liabilities:
Total Liabilities	10,300
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	194,660	261,061
Restricted cash	117,312	121,072
Loans held-for-investment, net	17,574,249	18,401,439
Loans held-for-sale	2,645,637	2,784,594
Investment securities	2,314,421	2,482,725
Properties, net	1,046,384	1,449,986
Properties held-for-sale	290,937
Investments of consolidated affordable housing fund		1,761,002
Investments in unconsolidated entities	104,976	105,434
Goodwill	259,846	259,846
Intangible assets	102,832	107,831
Derivative assets	63,437	108,621
Accrued interest receivable	200,867	168,796
Other assets	420,773	297,477
VIE assets, at fair value	0	0
Total Assets	27,349,164	28,309,884
Liabilities:
Dividends payable	152,888	151,511
Derivative liabilities	102,467	91,404
Secured financing agreements, net	13,888,753	14,522,698
Collateralized loan obligations and single asset securitization, net	3,491,292	3,676,224
Unsecured senior notes, net	2,158,888	2,329,211
Debt related to properties held-for-sale	193,691
VIE liabilities, at fair value	0	0
Total Liabilities	20,326,237	21,111,233
Temporary Equity: Redeemable non-controlling interests	414,348	362,790
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	3,208	3,181
Additional paid-in capital	5,864,670	5,807,087
Treasury stock	(138,022)	(138,022)
Retained earnings (accumulated deficit)	505,881	769,237
Accumulated other comprehensive income	15,352	20,955
Total Starwood Property Trust, Inc. Stockholders’ Equity	6,251,089	6,462,438
Non-controlling interests in consolidated subsidiaries	357,490	373,423
Total Permanent Equity	6,608,579	6,835,861
Total Liabilities and Equity	27,349,164	28,309,884
Subtotal | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	293,442	298,999
Subtotal | Related Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	44,816	41,186
Subtotal | Primary beneficiary
Assets:
Investments of consolidated affordable housing fund	2,012,833
Operating segment | Commercial and Residential Lending Segment
Assets:
Cash and cash equivalents	8,823	68,593
Restricted cash	23,902	18,556
Loans held-for-investment, net	15,069,389	16,038,930
Loans held-for-sale	2,604,594	2,763,458
Investment securities	1,147,829	1,250,893
Properties, net	431,155	463,492
Properties held-for-sale	0
Investments of consolidated affordable housing fund		0
Investments in unconsolidated entities	19,151	25,326
Goodwill	0	0
Intangible assets	13,415	11,908
Derivative assets	55,559	101,082
Accrued interest receivable	180,441	151,852
Other assets	301,436	170,177
VIE assets, at fair value	0	0
Total Assets	19,855,694	21,064,267
Liabilities:
Dividends payable	0	0
Derivative liabilities	54,066	21,523
Secured financing agreements, net	10,368,668	10,804,970
Collateralized loan obligations and single asset securitization, net	2,674,938	2,862,211
Unsecured senior notes, net	0	0
Debt related to properties held-for-sale	0
VIE liabilities, at fair value	0	0
Total Liabilities	13,203,908	13,835,601
Temporary Equity: Redeemable non-controlling interests	0	0
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	1,121,413	2,124,496
Treasury stock	0	0
Retained earnings (accumulated deficit)	5,514,906	5,083,100
Accumulated other comprehensive income	15,352	20,955
Total Starwood Property Trust, Inc. Stockholders’ Equity	6,651,671	7,228,551
Non-controlling interests in consolidated subsidiaries	115	115
Total Permanent Equity	6,651,786	7,228,666
Total Liabilities and Equity	19,855,694	21,064,267
Operating segment | Commercial and Residential Lending Segment | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	106,236	146,897
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
Operating segment | Infrastructure Lending Segment
Assets:
Cash and cash equivalents	56,300	31,153
Restricted cash	28,693	31,133
Loans held-for-investment, net	2,495,660	2,352,932
Loans held-for-sale	0	0
Investment securities	19,042	66,204
Properties, net	0	0
Properties held-for-sale	0
Investments of consolidated affordable housing fund		0
Investments in unconsolidated entities	52,691	47,078
Goodwill	119,409	119,409
Intangible assets	0	0
Derivative assets	84	122
Accrued interest receivable	12,485	9,856
Other assets	3,486	3,614
VIE assets, at fair value	0	0
Total Assets	2,787,850	2,661,501
Liabilities:
Dividends payable	0	0
Derivative liabilities	0	105
Secured financing agreements, net	1,088,965	1,042,679
Collateralized loan obligations and single asset securitization, net	816,354	814,013
Unsecured senior notes, net	0	0
Debt related to properties held-for-sale	0
VIE liabilities, at fair value	0	0
Total Liabilities	1,950,551	1,877,453
Temporary Equity: Redeemable non-controlling interests	0	0
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	664,621	683,258
Treasury stock	0	0
Retained earnings (accumulated deficit)	172,678	100,790
Accumulated other comprehensive income	0	0
Total Starwood Property Trust, Inc. Stockholders’ Equity	837,299	784,048
Non-controlling interests in consolidated subsidiaries	0	0
Total Permanent Equity	837,299	784,048
Total Liabilities and Equity	2,787,850	2,661,501
Operating segment | Infrastructure Lending Segment | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	45,232	20,656
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
Operating segment | Property Segment
Assets:
Cash and cash equivalents	19,957	31,194
Restricted cash	1,016	981
Loans held-for-investment, net	0	0
Loans held-for-sale	0	0
Investment securities	0	0
Properties, net	555,455	864,778
Properties held-for-sale	290,937
Investments of consolidated affordable housing fund		1,761,002
Investments in unconsolidated entities	0	0
Goodwill	0	0
Intangible assets	25,432	29,613
Derivative assets	5,638	1,803
Accrued interest receivable	1,502	863
Other assets	50,459	54,313
VIE assets, at fair value	0	0
Total Assets	2,963,229	2,744,547
Liabilities:
Dividends payable	0	0
Derivative liabilities	0	0
Secured financing agreements, net	598,350	789,719
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	804,266	801,435
Temporary Equity: Redeemable non-controlling interests	414,348	362,790
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	(437,169)	(405,955)
Treasury stock	0	0
Retained earnings (accumulated deficit)	1,974,539	1,777,643
Accumulated other comprehensive income	0	0
Total Starwood Property Trust, Inc. Stockholders’ Equity	1,537,370	1,371,688
Non-controlling interests in consolidated subsidiaries	207,245	208,634
Total Permanent Equity	1,744,615	1,580,322
Total Liabilities and Equity	2,963,229	2,744,547
Operating segment | Property Segment | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	12,225	11,716
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	2,012,833
Operating segment | Investing and Servicing Segment
Assets:
Cash and cash equivalents	22,011	39,023
Restricted cash	5,175	5,259
Loans held-for-investment, net	9,200	9,577
Loans held-for-sale	41,043	21,136
Investment securities	1,147,550	1,165,628
Properties, net	59,774	121,716
Properties held-for-sale	0
Investments of consolidated affordable housing fund		0
Investments in unconsolidated entities	33,134	33,030
Goodwill	140,437	140,437
Intangible assets	63,985	66,310
Derivative assets	2,156	5,614
Accrued interest receivable	1,369	1,105
Other assets	15,828	12,929
VIE assets, at fair value	0	0
Total Assets	1,541,662	1,621,764
Liabilities:
Dividends payable	0	0
Derivative liabilities	0	0
Secured financing agreements, net	495,857	543,256
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	540,309	589,633
Temporary Equity: Redeemable non-controlling interests	0	0
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	(705,176)	(646,662)
Treasury stock	0	0
Retained earnings (accumulated deficit)	1,556,399	1,514,119
Accumulated other comprehensive income	0	0
Total Starwood Property Trust, Inc. Stockholders’ Equity	851,223	867,457
Non-controlling interests in consolidated subsidiaries	150,130	164,674
Total Permanent Equity	1,001,353	1,032,131
Total Liabilities and Equity	1,541,662	1,621,764
Operating segment | Investing and Servicing Segment | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	44,452	46,377
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
Corporate
Assets:
Cash and cash equivalents	87,569	91,098
Restricted cash	58,526	65,143
Loans held-for-investment, net	0	0
Loans held-for-sale	0	0
Investment securities	0	0
Properties, net	0	0
Properties held-for-sale	0
Investments of consolidated affordable housing fund		0
Investments in unconsolidated entities	0	0
Goodwill	0	0
Intangible assets	0	0
Derivative assets	0	0
Accrued interest receivable	5,070	5,120
Other assets	49,564	56,444
VIE assets, at fair value	0	0
Total Assets	200,729	217,805
Liabilities:
Dividends payable	152,888	151,511
Derivative liabilities	48,401	69,776
Secured financing agreements, net	1,336,913	1,342,074
Collateralized loan obligations and single asset securitization, net	0	0
Unsecured senior notes, net	2,158,888	2,329,211
Debt related to properties held-for-sale	0
VIE liabilities, at fair value	0	0
Total Liabilities	3,827,203	4,007,111
Temporary Equity: Redeemable non-controlling interests	0	0
Starwood Property Trust, Inc. Stockholders’ Equity:
Common stock	3,208	3,181
Additional paid-in capital	5,220,981	4,051,950
Treasury stock	(138,022)	(138,022)
Retained earnings (accumulated deficit)	(8,712,641)	(7,706,415)
Accumulated other comprehensive income	0	0
Total Starwood Property Trust, Inc. Stockholders’ Equity	(3,626,474)	(3,789,306)
Non-controlling interests in consolidated subsidiaries	0	0
Total Permanent Equity	(3,626,474)	(3,789,306)
Total Liabilities and Equity	200,729	217,805
Corporate | Nonrelated Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	85,297	73,353
Corporate | Related Party
Liabilities:
Accounts payable, accrued expenses and other liabilities	44,816	41,186
Corporate | Primary beneficiary
Assets:
Investments of consolidated affordable housing fund	0
Securitization VIEs
Assets:
Cash and cash equivalents	0	0
Restricted cash	0	0
Loans held-for-investment, net	0	0
Loans held-for-sale	0	0
Investment securities	(1,578,859)	(1,666,921)
Properties, net	0	0
Properties held-for-sale	0
Investments of consolidated affordable housing fund		0
Investments in unconsolidated entities	(14,600)	(13,542)
Goodwill	0	0
Intangible assets	(37,865)	(39,058)
Derivative assets	0	0
Accrued interest receivable	0	(275)
Other assets	0	0
VIE assets, at fair value	43,786,356	52,453,041
Total Assets	42,155,032	50,733,245
Liabilities:
Dividends payable	0	0
Derivative liabilities	0	0
Secured financing agreements, net	(20,757)	(21,166)
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	42,175,734	50,754,355
Total Liabilities	42,154,977	50,733,189
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	56
Total Permanent Equity	55	56
Total Liabilities and Equity	42,155,032	50,733,245
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