Stockholders' Equity (Details 2) (USD $)	1 Months Ended			12 Months Ended			1 Months Ended			12 Months Ended			1 Months Ended				4 Months Ended	12 Months Ended		1 Months Ended			4 Months Ended	12 Months Ended
	May 31, 2011	Dec. 31, 2010	Aug. 31, 2009	Dec. 31, 2011	Aug. 17, 2009	Dec. 31, 2011 Starwood Property Trust, Inc. Equity Plan and Manager Equity Plan	Feb. 28, 2011 Starwood Property Trust, Inc. Equity Plan	Jul. 31, 2010 Starwood Property Trust, Inc. Equity Plan	Aug. 31, 2009 Starwood Property Trust, Inc. Equity Plan	Dec. 31, 2011 Starwood Property Trust, Inc. Equity Plan	Dec. 31, 2010 Starwood Property Trust, Inc. Equity Plan	Dec. 31, 2009 Starwood Property Trust, Inc. Equity Plan	Aug. 31, 2011 Starwood Property Trust, Inc. Manager Equity Plan	May 31, 2011 Starwood Property Trust, Inc. Manager Equity Plan	Dec. 31, 2010 Starwood Property Trust, Inc. Manager Equity Plan	Aug. 31, 2009 Starwood Property Trust, Inc. Manager Equity Plan	Dec. 31, 2009 Starwood Property Trust, Inc. Manager Equity Plan	Dec. 31, 2011 Starwood Property Trust, Inc. Manager Equity Plan	Dec. 31, 2010 Starwood Property Trust, Inc. Manager Equity Plan	Aug. 31, 2011 Starwood Property Trust, Inc. Non-Executive Director Stock Plan person	Aug. 31, 2010 Starwood Property Trust, Inc. Non-Executive Director Stock Plan person	Aug. 31, 2009 Starwood Property Trust, Inc. Non-Executive Director Stock Plan person	Dec. 31, 2009 Starwood Property Trust, Inc. Non-Executive Director Stock Plan	Dec. 31, 2011 Starwood Property Trust, Inc. Non-Executive Director Stock Plan	Dec. 31, 2010 Starwood Property Trust, Inc. Non-Executive Director Stock Plan
Equity Incentive Plans
Number of shares of common stock reserved for issuance						3,112,500																		100,000
Number of directors receiving grants of restricted stock																				4	4	4
Awards granted per director (in shares)																				2,877	1,000	2,200
Awards granted, fair value							$ 250,000		$ 100,000						$ 21,800,000	$ 20,800,000				$ 200,000,000	$ 75,000,000	$ 175,000
Award vesting period							3 years		3 years						3 years	3 years				1 year	1 year	3 years
Expenses related to the grant										$ 71,000	$ 16,000	$ 11,000					$ 2,400,000	$ 13,500,000	$ 7,400,000				$ 16,000	$ 179,000	$ 86,000
Vested to date (in shares)										3,694	1,250	417			432,292		86,458	704,164	432,292
Awards vesting each quarter (in shares)															89,583	86,458
Common stock issued under the award (in shares)								1,250
Issuance of common stock (in shares)	22,000,000	23,000,000	47,575,000										54,234	9,021
Stock issuance price (in dollars per share)	$ 21.67	$ 19.73			$ 20								$ 18.58	$ 22.08
Non-Vested Share and Share Equivalents activity
Beginning Balance (in shares)				1,690,809														1,680,208						10,601
Granted (in shares)				22,590			11,082		5,000	11,082					1,075,000	1,037,500								11,508
Vested (in shares)				(714,795)						(3,697)	(1,250)							(704,164)						(6,934)
Forfeited (in shares)								(3,750)
Balance at the end of period (in shares)		1,690,809		998,604						7,385					1,680,208			976,044	1,680,208					15,175	10,601
Vesting Schedule
2012 (in shares)				624,336						3,694								617,708						2,934
2013 (in shares)				374,268						3,691								358,336						12,241
Total (in shares)		1,690,809		998,604						7,385					1,680,208			976,044	1,680,208					15,175	10,601