Related-Party Transactions (Details) (USD $)	9 Months Ended	0 Months Ended	9 Months Ended	0 Months Ended		9 Months Ended		0 Months Ended				0 Months Ended		3 Months Ended		9 Months Ended			0 Months Ended	9 Months Ended	0 Months Ended	9 Months Ended		0 Months Ended			0 Months Ended
	Sep. 30, 2013	Sep. 13, 2013 Three-month EURIBOR	Sep. 30, 2013 LNR	Aug. 12, 2013 First mortgage and mezzanine loan item loan	Oct. 16, 2012 First mortgage and mezzanine loan	Sep. 30, 2013 First mortgage and mezzanine loan	Sep. 30, 2013 First mortgage and mezzanine loan Vornado	Oct. 16, 2012 Junior Mezzanine Loan	Aug. 12, 2013 First mortgage	Oct. 16, 2012 First mortgage	Mar. 27, 2013 First mortgage	Aug. 12, 2013 Mezzanine Loans	Sep. 13, 2013 EUR-denominated first mortgage loan item	Sep. 30, 2013 Manager	Sep. 30, 2012 Manager	Sep. 30, 2013 Manager	Sep. 30, 2012 Manager	Dec. 31, 2012 Manager	Apr. 17, 2013 Manager B Notes item	Sep. 30, 2013 Manager EUR-denominated first mortgage loan	Oct. 22, 2012 Starwood Distressed Opportunity Fund IX ("Fund IX")	Sep. 30, 2013 Starwood Distressed Opportunity Fund IX ("Fund IX")	Sep. 30, 2013 Starwood Distressed Opportunity Fund IX ("Fund IX") LNR	Oct. 22, 2012 Starwood Distressed Opportunity Fund IX ("Fund IX") First mortgage and mezzanine loan	Oct. 16, 2012 Starwood Distressed Opportunity Fund IX ("Fund IX") First mortgage and mezzanine loan	Sep. 30, 2013 Starwood Distressed Opportunity Fund IX ("Fund IX") First mortgage and mezzanine loan	May 17, 2013 Third party B Notes	Aug. 12, 2013 Starfin First mortgage and mezzanine loan	Sep. 13, 2013 Starfin EUR-denominated first mortgage loan
Related-Party Transactions
Initial term of management agreement																3 years
Term of each agreement extension																1 year
Base management fee incurred														$ 13,500,000	$ 8,500,000	$ 35,900,000	$ 23,300,000
Base management Fee Payable														13,500,000		13,500,000		0
Incentive fee incurred														4,800,000	2,100,000	4,800,000	7,500,000
Incentive fees payable														4,800,000		4,800,000		700,000
Incentive fees paid															2,300,000
Percentage of incentive fee paid in cash (as a percent)																50.00%
Percentage of incentive fee paid in stock (as a percent)																50.00%
Issuance of common stock (in shares)																50,203
Issuance price (in dollars per share)														$ 22.61		$ 22.61
Executive compensation and other reimbursable expenses														1,800,000	1,700,000	6,300,000	4,600,000
Executive compensation and other reimbursable expense payable														1,100,000		1,100,000		1,100,000
Co-origination of mortgage financing	2,506,378,000		264,517,000																						475,000,000
Mortgage financing to be funded at closing					137,500,000			237,500,000		237,500,000
Percentage of participation in mortgage financing						56.25%	25.00%																			18.75%
Percentage of participation in mortgage financing repurchased by entity											56.25%
Change in net interest (as a percent)						0.00%
Distribution from sales, net of fees																					43,900,000
Mortgage financing to be funded upon reaching certain milestones during transformation of property					100,000,000
Number of debt instruments																			2
Debt issued	8,760,000																										95,000,000
Debt issued																			146,700,000
Number of Class A office buildings with loans																			2
Number of retirement community unit collateralizing loan				109
Number of key nursing home collateralizing loan				30
Numbers of loans				2
Amount committed for loans by the entity				11,300,000
Amount committed for loans by the third party																												22,500,000
Interest rate (as a percent)									5.02%			15.12%
Term of loan									3 years			3 years
Loans initially funded													102,300,000
Loans initially funded for the entity													53,800,000
Loans initially funded for the third party																													48,500,000
Future funding													24,600,000							12,900,000
Future funding commitments by the entity													12,900,000
Future funding commitments by the third party																													11,700,000
Variable rate basis of loans	LIBOR or EURIBOR	three-month EURIBOR
Spread of loans (as a percent)	6.17%	0.70%
Number of retail properties													20
Percentage of participation sold in mortgage financing																								25.00%
Percentage of remaining interest of joint venture held by an affiliate																						50.00%
Obligation funded by an affiliate			6,200,000																				6,200,000
Related party payable	$ 6,200,000																						$ 6,200,000