Segment Data - Results of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenues:
Interest income from loans	$ 217,427	$ 183,416
Interest income from investment securities	15,240	17,632
Servicing fees	4,793	24,433
Rental income	74,146	83,833
Other revenues	954	1,166
Total revenues	312,560	310,480
Costs and expenses:
Management fees	40,728	23,466
Interest expense	120,025	134,672
General and administrative	38,702	34,930
Acquisition and investment pursuit costs	909	342
Costs of rental operations	28,214	29,651
Depreciation and amortization	23,980	29,254
Credit loss provision, net	48,669	763
Other expense	388	211
Total costs and expenses	301,615	253,289
Other (loss) income:
Change in net assets related to consolidated VIEs	(45,493)	47,836
Change in fair value of servicing rights	(393)	(767)
Change in fair value of investment securities, net	2,504	62
Change in fair value of mortgage loans, net	(16,134)	11,266
Earnings (loss) from unconsolidated entities	97	(43,200)
(Loss) gain on derivative financial instruments, net	296	4,485
Gain (loss) on derivative financial instruments, net	9,710	(2,207)
Foreign currency gain (loss), net	(34,486)	5,547
Loss on extinguishment of debt	(170)	(3,298)
Other income (loss), net	126	(73)
Total other (loss) income	(83,943)	19,651
(Loss) income before income taxes	(72,998)	76,842
Income tax benefit (provision)	6,729	(334)
Net (loss) income	(66,269)	76,508
Net income attributable to Starwood Property Trust, Inc.	(500)	(6,125)
Net (loss) income attributable to Starwood Property Trust, Inc.	(66,769)	70,383
Operating Segments and Corporate
Revenues:
Interest income from loans	217,427	183,416
Interest income from investment securities	44,129	45,086
Servicing fees	6,614	27,366
Rental income	74,146	83,833
Other revenues	956	1,184
Total revenues	343,272	340,885
Costs and expenses:
Management fees	40,697	23,417
Interest expense	120,187	134,832
General and administrative	38,618	34,842
Acquisition and investment pursuit costs	909	342
Costs of rental operations	28,214	29,651
Depreciation and amortization	23,980	29,254
Credit loss provision, net	48,669	763
Other expense	388	211
Total costs and expenses	301,662	253,312
Other (loss) income:
Change in fair value of servicing rights	318	(515)
Change in fair value of investment securities, net	(75,095)	16,446
Change in fair value of mortgage loans, net	(16,134)	11,266
Earnings (loss) from unconsolidated entities	671	(42,634)
(Loss) gain on derivative financial instruments, net	296	4,485
Gain (loss) on derivative financial instruments, net	9,710	(2,207)
Foreign currency gain (loss), net	(34,486)	5,547
Loss on extinguishment of debt	(170)	(3,298)
Other income (loss), net	126	(73)
Total other (loss) income	(114,764)	(10,983)
(Loss) income before income taxes	(73,154)	76,590
Income tax benefit (provision)	6,729	(334)
Net (loss) income	(66,425)	76,256
Net income attributable to Starwood Property Trust, Inc.	(344)	(5,873)
Net (loss) income attributable to Starwood Property Trust, Inc.	(66,769)	70,383
Operating segment | Commercial and Residential Lending Segment
Revenues:
Interest income from loans	192,381	154,595
Interest income from investment securities	18,628	19,908
Servicing fees	172	123
Rental income	78
Other revenues	178	204
Total revenues	211,437	174,830
Costs and expenses:
Management fees	351	411
Interest expense	53,950	61,604
General and administrative	8,132	6,768
Acquisition and investment pursuit costs	860	249
Costs of rental operations	778	19
Depreciation and amortization	415	71
Credit loss provision, net	40,217	(11)
Other expense	77	77
Total costs and expenses	104,780	69,188
Other (loss) income:
Change in fair value of investment securities, net	(27,879)	(1,694)
Change in fair value of mortgage loans, net	(35,517)	1,386
Earnings (loss) from unconsolidated entities	51	577
(Loss) gain on derivative financial instruments, net		2,755
Gain (loss) on derivative financial instruments, net	30,805	(9,297)
Foreign currency gain (loss), net	(34,001)	5,239
Total other (loss) income	(66,541)	(1,034)
(Loss) income before income taxes	40,116	104,608
Income tax benefit (provision)	4,422	248
Net (loss) income	44,538	104,856
Net income attributable to Starwood Property Trust, Inc.	(3)	(371)
Net (loss) income attributable to Starwood Property Trust, Inc.	44,535	104,485
Operating segment | Infrastructure Lending Segment
Revenues:
Interest income from loans	22,413	26,915
Interest income from investment securities	701	885
Other revenues	143	686
Total revenues	23,257	28,486
Costs and expenses:
Interest expense	13,117	18,577
General and administrative	4,423	4,479
Acquisition and investment pursuit costs	17	16
Depreciation and amortization	70
Credit loss provision, net	8,452	774
Total costs and expenses	26,079	23,846
Other (loss) income:
(Loss) gain on derivative financial instruments, net	296	790
Gain (loss) on derivative financial instruments, net	(1,001)	(395)
Foreign currency gain (loss), net	(473)	300
Loss on extinguishment of debt	(170)	(3,304)
Total other (loss) income	(1,348)	(2,609)
(Loss) income before income taxes	(4,170)	2,031
Income tax benefit (provision)	145	85
Net (loss) income	(4,025)	2,116
Net (loss) income attributable to Starwood Property Trust, Inc.	(4,025)	2,116
Operating segment | Investing and Servicing Segment
Revenues:
Interest income from loans	2,633	1,906
Interest income from investment securities	24,800	24,293
Servicing fees	6,442	27,243
Rental income	10,107	13,312
Other revenues	513	196
Total revenues	44,495	66,950
Costs and expenses:
Management fees	239	18
Interest expense	7,194	7,746
General and administrative	20,684	18,851
Acquisition and investment pursuit costs	20	77
Costs of rental operations	4,584	6,695
Depreciation and amortization	4,207	5,287
Total costs and expenses	36,928	38,674
Other (loss) income:
Change in fair value of servicing rights	318	(515)
Change in fair value of investment securities, net	(47,216)	18,140
Change in fair value of mortgage loans, net	19,383	9,880
Earnings (loss) from unconsolidated entities	620	594
(Loss) gain on derivative financial instruments, net		940
Gain (loss) on derivative financial instruments, net	(19,106)	(3,432)
Foreign currency gain (loss), net	7	(1)
Other income (loss), net	76
Total other (loss) income	(45,918)	25,606
(Loss) income before income taxes	(38,351)	53,882
Income tax benefit (provision)	2,162	(409)
Net (loss) income	(36,189)	53,473
Net income attributable to Starwood Property Trust, Inc.	4,770	215
Net (loss) income attributable to Starwood Property Trust, Inc.	(31,419)	53,688
Operating segment | Property Segment
Revenues:
Rental income	63,961	70,521
Other revenues	122	78
Total revenues	64,083	70,599
Costs and expenses:
Interest expense	17,121	18,990
General and administrative	1,078	1,518
Acquisition and investment pursuit costs	12
Costs of rental operations	22,852	22,937
Depreciation and amortization	19,288	23,896
Other expense	311	134
Total costs and expenses	60,662	67,475
Other (loss) income:
Earnings (loss) from unconsolidated entities		(43,805)
Gain (loss) on derivative financial instruments, net	(30,223)	1,290
Foreign currency gain (loss), net	(19)	9
Other income (loss), net	50
Total other (loss) income	(30,192)	(42,506)
(Loss) income before income taxes	(26,771)	(39,382)
Income tax benefit (provision)		(258)
Net (loss) income	(26,771)	(39,640)
Net income attributable to Starwood Property Trust, Inc.	(5,111)	(5,717)
Net (loss) income attributable to Starwood Property Trust, Inc.	(31,882)	(45,357)
Corporate
Revenues:
Other revenues		20
Total revenues		20
Costs and expenses:
Management fees	40,107	22,988
Interest expense	28,805	27,915
General and administrative	4,301	3,226
Total costs and expenses	73,213	54,129
Other (loss) income:
Gain (loss) on derivative financial instruments, net	29,235	9,627
Loss on extinguishment of debt		6
Other income (loss), net		(73)
Total other (loss) income	29,235	9,560
(Loss) income before income taxes	(43,978)	(44,549)
Net (loss) income	(43,978)	(44,549)
Net (loss) income attributable to Starwood Property Trust, Inc.	(43,978)	(44,549)
LNR VIEs
Revenues:
Interest income from investment securities	(28,889)	(27,454)
Servicing fees	(1,821)	(2,933)
Other revenues	(2)	(18)
Total revenues	(30,712)	(30,405)
Costs and expenses:
Management fees	31	49
Interest expense	(162)	(160)
General and administrative	84	88
Total costs and expenses	(47)	(23)
Other (loss) income:
Change in net assets related to consolidated VIEs	(45,493)	47,836
Change in fair value of servicing rights	(711)	(252)
Change in fair value of investment securities, net	77,599	(16,384)
Earnings (loss) from unconsolidated entities	(574)	(566)
Total other (loss) income	30,821	30,634
(Loss) income before income taxes	156	252
Net (loss) income	156	252
Net income attributable to Starwood Property Trust, Inc.	$ (156)	$ (252)