Acquisitions (Details) $ / shares in Units, $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2016 USD ($) item $ / shares	Mar. 31, 2016 item	Jun. 30, 2015 USD ($) $ / shares	Jun. 30, 2016 USD ($) item $ / shares	Jun. 30, 2015 USD ($) $ / shares	Dec. 31, 2015 USD ($) ft² property item	Jun. 29, 2016 USD ($)
Liabilities assumed:
Revenues	$ 199,992		$ 178,660	$ 395,485	$ 357,509
Net income (loss)	112,071		117,640	139,117	238,419
Bargain purchase gains				8,406
Depreciation and amortization				34,664	9,079
Gain (loss) on derivative financial instruments, net	20,253		(19,530)	(4,465)	5,093
Goodwill	140,437			140,437		$ 140,437
Pro forma revenue and net income
Revenues				405,577	428,261
Net income attributable to STWD				$ 131,819	$ 237,563
Net income per share - Basic | $ / shares				$ 0.55	$ 1.03
Net income per share - Diluted | $ / shares				$ 0.55	$ 1.02
Woodstar Portfolio, Ireland Portfolio and REIS Portfolio
Pro forma revenue and net income
Revenues	202,304		212,251
Net income attributable to STWD	$ 102,983		$ 115,354
Net income per share - Basic | $ / shares	$ 0.43		$ 0.49
Net income per share - Diluted | $ / shares	$ 0.43		$ 0.48
Management fee expense addition	$ 175		$ 1,966	$ 663	$ 4,335
Woodstar Portfolio
Acquisitions
Number of properties in portfolio investment | item	32			32
Weighted average occupancy percentage				98.00%
Number of units | item	8,948			8,948
Number of acquired properties closed | item	2	12		14
Number of units acquired | item	628			3,710
Assets acquired:
Cash and cash equivalents	$ 6,254			$ 6,254
Properties	245,430			245,430		339,040
Intangible assets	8,174			8,174		11,337
Other assets	16,417			16,417		652
Total assets acquired	276,275			276,275		351,029	$ 48,900
Liabilities assumed:
Accounts payable, accrued expenses and other liabilities	19,666			19,666		18,030
Secured financing agreements	150,763			150,763		8,982
Total liabilities assumed	170,429			170,429		27,012	$ 22,100
Net assets acquired	105,846			105,846		$ 324,017
Revenues				14,600
Net income (loss)				5,000
Bargain purchase gains	8,400			8,400
Depreciation and amortization				9,000
Acquisition related costs				800
Goodwill	0			0
Ireland Portfolio
Acquisitions
Number of properties in portfolio investment | property						13
Area of property | ft²						600,000
Assets acquired:
Restricted cash						$ 10,829
Properties						445,369
Intangible assets						59,529
Other assets						2,508
Total assets acquired						518,235
Liabilities assumed:
Accounts payable, accrued expenses and other liabilities						17,552
Secured financing agreements						283,010
Total liabilities assumed						300,562
Net assets acquired						217,673
Goodwill						0
Ireland Portfolio | Lender 6 Mortgage Facility
Acquisitions
Debt incurred to partially fund acquisition						328,600
REO Portfolio
Assets acquired:
Properties	68,096			68,096		128,218
Intangible assets	25,387			25,387		19,381
Other assets	2,858			2,858		4,973
Total assets acquired	96,341			96,341		152,572
Liabilities assumed:
Accounts payable, accrued expenses and other liabilities	3,063			3,063		6,998
Total liabilities assumed	3,063			3,063		6,998
Non-controlling interests	5,492			5,492		6,904
Net assets acquired	87,786			87,786		$ 138,670
Net Leased Office Property | Ireland Portfolio
Acquisitions
Number of acquired properties closed | property						12
Multifamily Property | Ireland Portfolio
Acquisitions
Number of acquired properties closed | property						1
Investment and Servicing Segment | REO Portfolio
Acquisitions
Number of acquired properties closed | item						14
Purchase price	58,000			87,800		$ 138,700
Purchase price of properties - non-performing loans	8,200			8,200
Liabilities assumed:
Goodwill	$ 0			$ 0