Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Apr. 19, 2013 segment	Sep. 30, 2013 segment	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting
Number of reportable business segments			1	3
Revenues
Interest income from loans	$ 94,045	$ 56,261			$ 236,671	$ 179,078
Interest income from investment securities	17,804	16,585			52,621	40,404
Servicing fees	36,509				75,644
Other revenues	2,098	66			4,077	180
Rental income	5,080	59			8,733	59
Total revenues	155,536	72,971			377,746	219,721
Costs and expenses:
Management fees	24,235	14,659			58,675	42,673
Interest expense	36,743	12,030			77,678	34,345
General and administrative	48,335	3,084			97,769	8,838
Business combination costs	342				17,958
Acquisition and investment pursuit costs	1,177	622			4,495	2,737
Residential segment, other operating costs	6,023	327			10,622	327
Depreciation and amortization	4,988	78			8,644	78
Loan loss allowance	1,160				1,915
Other expense	304				533
Total costs and expenses	123,307	30,800			278,289	88,998
Income before other income (loss), income taxes and non-controlling interests	32,229	42,171			99,457	130,723
Other income:
Income of consolidated VIEs, net	47,963				79,912
Change in fair value of servicing rights	(1,867)				1,031
Change in fair value of investment securities, net	(2,278)				(3,265)
Change in fair value of mortgage loans held-for-sale, net	25,857				26,315	(5,760)
Earnings from unconsolidated entities	4,577	787			10,915	2,739
Gain (loss) on sale of investments, net	8,059	9,017			22,968	19,147
Loss on derivative financial instruments, net	(22,451)	(7,561)			(65)	(9,784)
Foreign currency gain, net	9,580	6,725			3,495	11,222
OTTI	(52)	(676)			(453)	(2,728)
Other income	3,705	180			3,744	530
Total other income	73,093	8,472			144,597	15,366
Income before income taxes and non-controlling interests	105,322	50,643			244,054	146,089
Income tax provision	13,721	301			25,691	840
Net income	91,601	50,342			218,363	145,249
Net income attributable to non-controlling interests	1,886	130			4,124	388
Net income attributable to Starwood Property Trust, Inc.	89,715	50,212			214,239	144,861
Real Estate Investment Lending
Revenues
Interest income from loans	90,837	56,261			231,203	179,078
Interest income from investment securities	12,301	16,585			42,179	40,404
Other revenues	116	64			291	178
Total revenues	103,254	72,910			273,673	219,660
Costs and expenses:
Management fees	15,581	14,563			44,504	42,526
Interest expense	29,866	12,030			66,794	34,345
General and administrative	3,748	3,084			11,401	8,838
Business combination costs	342				17,958
Acquisition and investment pursuit costs	742	465			1,787	2,032
Loan loss allowance	1,160				1,915
Other expense	59				150
Total costs and expenses	51,498	30,142			144,509	87,741
Income before other income (loss), income taxes and non-controlling interests	51,756	42,768			129,164	131,919
Other income:
Change in fair value of investment securities, net	(157)				(83)
Change in fair value of mortgage loans held-for-sale, net						(5,760)
Earnings from unconsolidated entities	896	787			3,488	2,739
Gain (loss) on sale of investments, net	6,184	9,019			19,690	19,149
Loss on derivative financial instruments, net	(17,166)	(7,561)			(2,939)	(9,784)
Foreign currency gain, net	9,555	6,725			3,537	11,222
OTTI	(52)	(676)			(453)	(2,728)
Other income		180				530
Total other income	(740)	8,474			23,240	15,368
Income before income taxes and non-controlling interests	51,016	51,242			152,404	147,287
Income tax provision	619	301			1,645	840
Net income	50,397	50,941			150,759	146,447
Net income attributable to non-controlling interests	1,451	130			3,599	388
Net income attributable to Starwood Property Trust, Inc.	48,946	50,811			147,160	146,059
Single Family Residential
Revenues
Other revenues	75	2			180	2
Rental income	5,080	59			8,733	59
Total revenues	5,155	61			8,913	61
Costs and expenses:
Management fees	3,310	96			6,535	147
Interest expense	2,287				3,587
General and administrative	652				1,713
Acquisition and investment pursuit costs	223	157			2,105	705
Residential segment, other operating costs	6,023	327			10,622	327
Depreciation and amortization	1,553	78			2,981	78
Total costs and expenses	14,048	658			27,543	1,257
Income before other income (loss), income taxes and non-controlling interests	(8,893)	(597)			(18,630)	(1,196)
Other income:
Gain (loss) on sale of investments, net	1,875	(2)			3,278	(2)
Other income	3,320				3,320
Total other income	5,195	(2)			6,598	(2)
Income before income taxes and non-controlling interests	(3,698)	(599)			(12,032)	(1,198)
Income tax provision					12
Net income	(3,698)	(599)			(12,044)	(1,198)
Net income attributable to non-controlling interests	16
Net income attributable to Starwood Property Trust, Inc.	(3,714)	(599)			(12,044)	(1,198)
LNR
Revenues
Interest income from loans	3,208				5,468
Interest income from investment securities	18,792				30,550
Servicing fees	59,566				112,426
Other revenues	2,229				4,201
Total revenues	83,795				152,645
Costs and expenses:
Management fees	5,298				7,572
Interest expense	4,590				7,297
General and administrative	43,752				84,325
Acquisition and investment pursuit costs	212				603
Depreciation and amortization	3,435				5,663
Other expense	245				383
Total costs and expenses	57,532				105,843
Income before other income (loss), income taxes and non-controlling interests	26,263				46,802
Other income:
Change in fair value of servicing rights	(3,939)				2,175
Change in fair value of investment securities, net	9,820				16,208
Change in fair value of mortgage loans held-for-sale, net	25,857				26,315
Earnings from unconsolidated entities	4,459				8,401
Loss on derivative financial instruments, net	(5,285)				2,874
Foreign currency gain, net	25				(42)
Other income	385				424
Total other income	31,322				56,355
Income before income taxes and non-controlling interests	57,585				103,157
Income tax provision	13,102				24,034
Net income	44,483				79,123
Net income attributable to Starwood Property Trust, Inc.	44,483				79,123
Subtotal
Revenues
Interest income from loans	94,045				236,671
Interest income from investment securities	31,093				72,729
Servicing fees	59,566				112,426
Other revenues	2,420				4,672
Rental income	5,080				8,733
Total revenues	192,204				435,231
Costs and expenses:
Management fees	24,189				58,611
Interest expense	36,743				77,678
General and administrative	48,152				97,439
Business combination costs	342				17,958
Acquisition and investment pursuit costs	1,177				4,495
Residential segment, other operating costs	6,023				10,622
Depreciation and amortization	4,988				8,644
Loan loss allowance	1,160				1,915
Other expense	304				533
Total costs and expenses	123,078				277,895
Income before other income (loss), income taxes and non-controlling interests	69,126				157,336
Other income:
Change in fair value of servicing rights	(3,939)				2,175
Change in fair value of investment securities, net	9,663				16,125
Change in fair value of mortgage loans held-for-sale, net	25,857				26,315
Earnings from unconsolidated entities	5,355				11,889
Gain (loss) on sale of investments, net	8,059				22,968
Loss on derivative financial instruments, net	(22,451)				(65)
Foreign currency gain, net	9,580				3,495
OTTI	(52)				(453)
Other income	3,705				3,744
Total other income	35,777				86,193
Income before income taxes and non-controlling interests	104,903				243,529
Income tax provision	13,721				25,691
Net income	91,182				217,838
Net income attributable to non-controlling interests	1,467				3,599
Net income attributable to Starwood Property Trust, Inc.	89,715				214,239
LNR VIEs
Revenues
Interest income from investment securities	(13,289)				(20,108)
Servicing fees	(23,057)				(36,782)
Other revenues	(322)				(595)
Total revenues	(36,668)				(57,485)
Costs and expenses:
Management fees	46				64
General and administrative	183				330
Total costs and expenses	229				394
Income before other income (loss), income taxes and non-controlling interests	(36,897)				(57,879)
Other income:
Income of consolidated VIEs, net	47,963				79,912
Change in fair value of servicing rights	2,072				(1,144)
Change in fair value of investment securities, net	(11,941)				(19,390)
Earnings from unconsolidated entities	(778)				(974)
Total other income	37,316				58,404
Income before income taxes and non-controlling interests	419				525
Net income	419				525
Net income attributable to non-controlling interests	$ 419				$ 525