Segment and Geographic Data - Results of Operations (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Mar. 31, 2015	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Interest income from loans										$ 467,195	$ 477,931	$ 434,662
Interest income from investment securities										70,848	93,665	112,016
Servicing fees										88,956	117,068	135,565
Rental income										152,760	36,622	9,831
Other revenues										4,908	10,591	10,801
Total revenues		$ 184,477	$ 204,705	$ 199,992	$ 195,493	$ 186,223	$ 192,145	$ 178,660	$ 178,849	784,667	735,877	702,875
Costs and expenses:
Management fees										117,451	124,733	117,732
Interest expense										230,799	202,550	161,104
General and administrative										152,941	154,628	169,661
Acquisition and investment pursuit costs										13,462	13,429	3,681
Costs of rental operations										65,101	11,542	5,938
Depreciation and amortization										66,786	29,010	16,627
Loan loss allowance, net										3,759	(2)	2,047
Other expense										100	389	7,219
Total costs and expenses										650,399	536,279	484,009
Income before other income, income taxes and non-controlling interests										134,268	199,598	218,866
Other income:
Change in net assets related to consolidated VIEs										151,593	185,490	212,506
Change in fair value of servicing rights										(47,149)	(12,605)	(16,787)
Change in fair value of investment securities, net										(1,401)	3,084	15,077
Change in fair value of mortgage loans held-for-sale, net										74,251	64,320	70,420
Earnings from unconsolidated entities										21,723	26,674	19,932
Gain on sale of investments and other assets, net										1,942	22,664	12,886
Gain (loss) on derivative financial instruments, net										70,734	21,598	20,451
Foreign currency (loss), gain net										(33,967)	(37,221)	(29,942)
OTTI/Impairment										(728)		(1,056)
Loss on extinguishment of debt										(8,781)	(5,921)
Other income, net										13,510	1,708	3,832
Total other income										241,727	269,791	307,319
Income from continuing operations before income taxes										375,995	469,389	526,185
Income tax benefit (provision)										(8,344)	(17,206)	(24,096)
Income from continuing operations										367,651	452,183	502,089
Loss from discontinued operations, net of tax												(1,551)
Net income		122,721	105,813	112,071	27,046	96,648	117,116	117,640	120,779	367,651	452,183	500,538
Net income attributable to non-controlling interests										(2,465)	(1,486)	(5,517)
Net income attributable to Starwood Property Trust, Inc.		$ 121,290	$ 105,766	$ 111,473	$ 26,657	$ 96,451	$ 116,735	$ 117,148	$ 120,363	365,186	450,697	495,021
Investment and Servicing Segment
Other income:
Gain on sale of investments and other assets, net	$ 17,800
Operating Segments and Corporate
Revenues:
Interest income from loans										467,195	477,931	434,662
Interest income from investment securities										193,933	224,424	178,167
Servicing fees										145,723	216,198	227,475
Rental income										152,760	36,622	9,831
Other revenues										5,559	11,525	12,025
Total revenues										965,170	966,700	862,160
Costs and expenses:
Management fees										117,255	124,505	117,562
Interest expense										231,259	202,550	161,104
General and administrative										152,238	153,911	168,938
Acquisition and investment pursuit costs										13,462	13,429	3,681
Costs of rental operations										65,101	11,542	5,938
Depreciation and amortization										66,786	29,010	16,627
Loan loss allowance, net										3,759	(2)	2,047
Other expense										100	389	7,219
Total costs and expenses										649,960	535,334	483,116
Income before other income, income taxes and non-controlling interests										315,210	431,366	379,044
Other income:
Change in fair value of servicing rights										(43,258)	(46,831)	(53,065)
Change in fair value of investment securities, net										(44,074)	(9,743)	98,545
Change in fair value of mortgage loans held-for-sale, net										74,251	64,320	70,420
Earnings from unconsolidated entities										22,120	27,177	23,270
Gain on sale of investments and other assets, net										1,942	22,664	12,886
Gain (loss) on derivative financial instruments, net										70,734	21,598	20,451
Foreign currency (loss), gain net										(33,967)	(37,221)	(29,942)
OTTI/Impairment										(728)		(1,056)
Loss on extinguishment of debt										(8,781)	(5,921)
Other income, net										22,332	1,708	3,832
Total other income										60,571	37,751	145,341
Income from continuing operations before income taxes										375,781	469,117	524,385
Income tax benefit (provision)										(8,344)	(17,206)	(24,096)
Income from continuing operations												500,289
Loss from discontinued operations, net of tax												(1,551)
Net income										367,437	451,911	498,738
Net income attributable to non-controlling interests										(2,251)	(1,214)	(3,717)
Net income attributable to Starwood Property Trust, Inc.										365,186	450,697	495,021
Operating segment | Lending Segment
Revenues:
Interest income from loans										449,470	460,365	420,683
Interest income from investment securities										47,241	68,059	68,348
Servicing fees										782	428	330
Other revenues										242	597	406
Total revenues										497,735	529,449	489,767
Costs and expenses:
Management fees										1,829	901	2,079
Interest expense										88,000	81,676	65,913
General and administrative										18,517	21,685	21,551
Acquisition and investment pursuit costs										1,665	2,065	2,023
Loan loss allowance, net										3,759	(2)	2,047
Other expense											6	52
Total costs and expenses										113,770	106,331	93,665
Income before other income, income taxes and non-controlling interests										383,965	423,118	396,102
Other income:
Change in fair value of investment securities, net										20	209	822
Earnings from unconsolidated entities										3,447	4,045	7,484
Gain on sale of investments and other assets, net										1,716	4,839	12,886
Gain (loss) on derivative financial instruments, net										41,576	30,764	30,713
Foreign currency (loss), gain net										(37,595)	(36,956)	(29,139)
OTTI/Impairment												(259)
Other income, net												(327)
Total other income										9,164	2,901	22,180
Income from continuing operations before income taxes										393,129	426,019	418,282
Income tax benefit (provision)										1,610	(242)	(1,476)
Income from continuing operations												416,806
Net income										394,739	425,777	416,806
Net income attributable to non-controlling interests										(1,398)	(1,389)	(3,717)
Net income attributable to Starwood Property Trust, Inc.										393,341	424,388	413,089
Operating segment | Investment and Servicing Segment
Revenues:
Interest income from loans										17,725	17,566	13,979
Interest income from investment securities										146,692	156,365	109,819
Servicing fees										144,941	215,770	227,145
Rental income										38,223	11,177	9,831
Other revenues										5,255	10,928	11,619
Total revenues										352,836	411,806	372,393
Costs and expenses:
Management fees										78	72	72
Interest expense										15,983	10,386	4,781
General and administrative										121,140	123,746	141,500
Acquisition and investment pursuit costs										2,520	2,375	1,206
Costs of rental operations										17,638	6,121	5,938
Depreciation and amortization										16,117	13,972	16,627
Other expense										100	383	7,167
Total costs and expenses										173,576	157,055	177,291
Income before other income, income taxes and non-controlling interests										179,260	254,751	195,102
Other income:
Change in fair value of servicing rights										(43,258)	(46,831)	(53,065)
Change in fair value of investment securities, net										(44,094)	(9,952)	97,723
Change in fair value of mortgage loans held-for-sale, net										74,251	64,320	70,420
Earnings from unconsolidated entities										8,937	13,042	13,610
Gain on sale of investments and other assets, net										226	17,825
Gain (loss) on derivative financial instruments, net										(4,318)	(14,226)	(10,262)
Foreign currency (loss), gain net										3,661	(296)	(803)
OTTI/Impairment										(215)		(797)
Other income, net										8,959	161	4,159
Total other income										4,149	24,043	120,985
Income from continuing operations before income taxes										183,409	278,794	316,087
Income tax benefit (provision)										(9,954)	(16,964)	(22,620)
Income from continuing operations												293,467
Net income										173,455	261,830	293,467
Net income attributable to non-controlling interests										(853)	175
Net income attributable to Starwood Property Trust, Inc.										172,602	262,005	293,467
Operating segment | Property Segment
Revenues:
Rental income										114,537	25,445
Other revenues										62
Total revenues										114,599	25,445
Costs and expenses:
Interest expense										22,009	5,584
General and administrative										3,338	1,205
Acquisition and investment pursuit costs										7,886	8,951
Costs of rental operations										47,463	5,421
Depreciation and amortization										50,669	15,038
Total costs and expenses										131,365	36,199
Income before other income, income taxes and non-controlling interests										(16,766)	(10,754)
Other income:
Earnings from unconsolidated entities										9,736	10,090	2,176
Gain (loss) on derivative financial instruments, net										33,476	5,060
Foreign currency (loss), gain net										(38)	31
OTTI/Impairment										(513)
Other income, net										9,102	1,530
Total other income										51,763	16,711	2,176
Income from continuing operations before income taxes										34,997	5,957	2,176
Income from continuing operations												2,176
Net income										34,997	5,957	2,176
Net income attributable to Starwood Property Trust, Inc.										34,997	5,957	2,176
Operating segment | Single Family Residential
Other income:
Loss from discontinued operations, net of tax												(1,551)
Net income												(1,551)
Net income attributable to Starwood Property Trust, Inc.												(1,551)
Corporate
Costs and expenses:
Management fees										115,348	123,532	115,411
Interest expense										105,267	104,904	90,410
General and administrative										9,243	7,275	5,887
Acquisition and investment pursuit costs										1,391	38	452
Total costs and expenses										231,249	235,749	212,160
Income before other income, income taxes and non-controlling interests										(231,249)	(235,749)	(212,160)
Other income:
Foreign currency (loss), gain net										5
Loss on extinguishment of debt										(8,781)	(5,921)
Other income, net										4,271	17
Total other income										(4,505)	(5,904)
Income from continuing operations before income taxes										(235,754)	(241,653)	(212,160)
Income from continuing operations												(212,160)
Net income										(235,754)	(241,653)	(212,160)
Net income attributable to Starwood Property Trust, Inc.										(235,754)	(241,653)	(212,160)
Investment and Servicing VIEs
Revenues:
Interest income from investment securities										(123,085)	(130,759)	(66,151)
Servicing fees										(56,767)	(99,130)	(91,910)
Other revenues										(651)	(934)	(1,224)
Total revenues										(180,503)	(230,823)	(159,285)
Costs and expenses:
Management fees										196	228	170
Interest expense										(460)
General and administrative										703	717	723
Total costs and expenses										439	945	893
Income before other income, income taxes and non-controlling interests										(180,942)	(231,768)	(160,178)
Other income:
Change in net assets related to consolidated VIEs										151,593	185,490	212,506
Change in fair value of servicing rights										(3,891)	34,226	36,278
Change in fair value of investment securities, net										42,673	12,827	(83,468)
Earnings from unconsolidated entities										(397)	(503)	(3,338)
Other income, net										(8,822)
Total other income										181,156	232,040	161,978
Income from continuing operations before income taxes										214	272	1,800
Income from continuing operations												1,800
Net income										214	272	1,800
Net income attributable to non-controlling interests										$ (214)	$ (272)	$ (1,800)