Segment and Geographic Data - Results of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues:
Interest income from loans	$ 190,575	$ 217,427
Interest income from investment securities	11,610	15,240
Servicing fees	8,402	4,793
Rental income	76,338	74,146
Other revenues	305	954
Total revenues	287,230	312,560
Costs and expenses:
Management fees	38,736	40,728
Interest expense	103,374	120,025
General and administrative	38,636	38,702
Acquisition and investment pursuit costs	185	909
Costs of rental operations	28,745	28,214
Depreciation and amortization	22,474	23,980
Credit loss provision (reversal), net	44	48,669
Other expense	685	388
Total costs and expenses	232,879	301,615
Other income (loss):
Change in net assets related to consolidated VIEs	39,745	(45,493)
Change in fair value of servicing rights	(796)	(393)
Change in fair value of investment securities, net	(306)	2,504
Change in fair value of mortgage loans, net	(9,478)	(16,134)
Earnings from unconsolidated entities	1,734	97
(Loss) gain on sale of investments and other assets, net	17,693	296
(Loss) gain on derivative financial instruments, net	33,989	9,710
Foreign currency (loss) gain, net	(11,681)	(34,486)
Add: Loss on extinguishment of Convertible Notes	(516)	(170)
Other income, net	21	126
Total other income (loss)	70,405	(83,943)
Income (loss) before income taxes	124,756	(72,998)
Income tax (provision) benefit	(2,230)	6,729
Net income (loss)	122,526	(66,269)
Net income attributable to non-controlling interests	(11,148)	(500)
Net income (loss) attributable to Starwood Property Trust, Inc.	111,378	(66,769)
Operating Segments and Corporate
Revenues:
Interest income from loans	190,575	217,427
Interest income from investment securities	39,889	44,129
Servicing fees	12,580	6,614
Rental income	76,338	74,146
Other revenues	305	956
Total revenues	319,687	343,272
Costs and expenses:
Management fees	38,725	40,697
Interest expense	103,565	120,187
General and administrative	38,549	38,618
Acquisition and investment pursuit costs	185	909
Costs of rental operations	28,745	28,214
Depreciation and amortization	22,474	23,980
Credit loss provision (reversal), net	44	48,669
Other expense	685	388
Total costs and expenses	232,972	301,662
Other income (loss):
Change in fair value of servicing rights	745	318
Change in fair value of investment securities, net	5,120	(75,095)
Change in fair value of mortgage loans, net	(9,478)	(16,134)
Earnings from unconsolidated entities	2,088	671
(Loss) gain on sale of investments and other assets, net	17,693	296
(Loss) gain on derivative financial instruments, net	33,989	9,710
Foreign currency (loss) gain, net	(11,681)	(34,486)
Add: Loss on extinguishment of Convertible Notes	(516)	(170)
Other income, net	21	126
Total other income (loss)	37,981	(114,764)
Income (loss) before income taxes	124,696	(73,154)
Income tax (provision) benefit	(2,230)	6,729
Net income (loss)	122,466	(66,425)
Net income attributable to non-controlling interests	(11,088)	(344)
Net income (loss) attributable to Starwood Property Trust, Inc.	111,378	(66,769)
Operating segment | Commercial and Residential Lending Segment
Revenues:
Interest income from loans	170,593	192,381
Interest income from investment securities	18,385	18,628
Servicing fees	124	172
Rental income	1,339	78
Other revenues	90	178
Total revenues	190,531	211,437
Costs and expenses:
Management fees	315	351
Interest expense	44,295	53,950
General and administrative	11,333	8,132
Acquisition and investment pursuit costs	185	860
Costs of rental operations	477	778
Depreciation and amortization	307	415
Credit loss provision (reversal), net	(529)	40,217
Other expense	31	77
Total costs and expenses	56,414	104,780
Other income (loss):
Change in fair value of investment securities, net	(2,050)	(27,879)
Change in fair value of mortgage loans, net	(10,714)	(35,517)
Earnings from unconsolidated entities	1,753	51
(Loss) gain on sale of investments and other assets, net	17,693
(Loss) gain on derivative financial instruments, net	26,141	30,805
Foreign currency (loss) gain, net	(11,594)	(34,001)
Add: Loss on extinguishment of Convertible Notes	(68)
Total other income (loss)	21,161	(66,541)
Income (loss) before income taxes	155,278	40,116
Income tax (provision) benefit	(1,505)	4,422
Net income (loss)	153,773	44,538
Net income attributable to non-controlling interests	(3)	(3)
Net income (loss) attributable to Starwood Property Trust, Inc.	153,770	44,535
Operating segment | Infrastructure Lending Segment
Revenues:
Interest income from loans	18,808	22,413
Interest income from investment securities	564	701
Other revenues	93	143
Total revenues	19,465	23,257
Costs and expenses:
Interest expense	8,841	13,117
General and administrative	3,442	4,423
Acquisition and investment pursuit costs		17
Depreciation and amortization	100	70
Credit loss provision (reversal), net	573	8,452
Total costs and expenses	12,956	26,079
Other income (loss):
Earnings from unconsolidated entities	(254)
(Loss) gain on sale of investments and other assets, net		296
(Loss) gain on derivative financial instruments, net	684	(1,001)
Foreign currency (loss) gain, net	(49)	(473)
Add: Loss on extinguishment of Convertible Notes	(307)	(170)
Other income, net	21
Total other income (loss)	95	(1,348)
Income (loss) before income taxes	6,604	(4,170)
Income tax (provision) benefit	(92)	145
Net income (loss)	6,512	(4,025)
Net income (loss) attributable to Starwood Property Trust, Inc.	6,512	(4,025)
Operating segment | Investing and Servicing Segment
Revenues:
Interest income from loans	1,174	2,633
Interest income from investment securities	20,940	24,800
Servicing fees	12,456	6,442
Rental income	9,895	10,107
Other revenues	82	513
Total revenues	44,547	44,495
Costs and expenses:
Management fees	222	239
Interest expense	5,449	7,194
General and administrative	18,440	20,684
Acquisition and investment pursuit costs		20
Costs of rental operations	4,308	4,584
Depreciation and amortization	3,967	4,207
Other expense	71
Total costs and expenses	32,457	36,928
Other income (loss):
Change in fair value of servicing rights	745	318
Change in fair value of investment securities, net	7,170	(47,216)
Change in fair value of mortgage loans, net	1,236	19,383
Earnings from unconsolidated entities	589	620
(Loss) gain on derivative financial instruments, net	9,283	(19,106)
Foreign currency (loss) gain, net	(63)	7
Other income, net		76
Total other income (loss)	18,960	(45,918)
Income (loss) before income taxes	31,050	(38,351)
Income tax (provision) benefit	(633)	2,162
Net income (loss)	30,417	(36,189)
Net income attributable to non-controlling interests	(6,008)	4,770
Net income (loss) attributable to Starwood Property Trust, Inc.	24,409	(31,419)
Operating segment | Property Segment
Revenues:
Rental income	65,104	63,961
Other revenues	40	122
Total revenues	65,144	64,083
Costs and expenses:
Interest expense	15,832	17,121
General and administrative	1,023	1,078
Acquisition and investment pursuit costs		12
Costs of rental operations	23,960	22,852
Depreciation and amortization	18,100	19,288
Other expense	583	311
Total costs and expenses	59,498	60,662
Other income (loss):
(Loss) gain on derivative financial instruments, net	4,724	(30,223)
Foreign currency (loss) gain, net	25	(19)
Add: Loss on extinguishment of Convertible Notes	(141)
Other income, net		50
Total other income (loss)	4,608	(30,192)
Income (loss) before income taxes	10,254	(26,771)
Net income (loss)	10,254	(26,771)
Net income attributable to non-controlling interests	(5,077)	(5,111)
Net income (loss) attributable to Starwood Property Trust, Inc.	5,177	(31,882)
Corporate
Costs and expenses:
Management fees	38,188	40,107
Interest expense	29,148	28,805
General and administrative	4,311	4,301
Total costs and expenses	71,647	73,213
Other income (loss):
(Loss) gain on derivative financial instruments, net	(6,843)	29,235
Total other income (loss)	(6,843)	29,235
Income (loss) before income taxes	(78,490)	(43,978)
Net income (loss)	(78,490)	(43,978)
Net income (loss) attributable to Starwood Property Trust, Inc.	(78,490)	(43,978)
LNR VIEs
Revenues:
Interest income from investment securities	(28,279)	(28,889)
Servicing fees	(4,178)	(1,821)
Other revenues		(2)
Total revenues	(32,457)	(30,712)
Costs and expenses:
Management fees	11	31
Interest expense	(191)	(162)
General and administrative	87	84
Total costs and expenses	(93)	(47)
Other income (loss):
Change in net assets related to consolidated VIEs	39,745	(45,493)
Change in fair value of servicing rights	(1,541)	(711)
Change in fair value of investment securities, net	(5,426)	77,599
Earnings from unconsolidated entities	(354)	(574)
Total other income (loss)	32,424	30,821
Income (loss) before income taxes	60	156
Net income (loss)	60	156
Net income attributable to non-controlling interests	$ (60)	$ (156)