Acquisitions, Dispositions, Leasing and Financing Activities (Details Textual) (USD $)	3 Months Ended			1 Months Ended	3 Months Ended			1 Months Ended	3 Months Ended				1 Months Ended						3 Months Ended		3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Jan. 31, 2013 Playa Vista Mezzanine Loan [Member] sqft	Mar. 31, 2013 Playa Vista Mezzanine Loan [Member]	Mar. 01, 2013 Playa Vista Mezzanine Loan [Member]	Jan. 24, 2013 Playa Vista Mezzanine Loan [Member]	Jan. 25, 2013 Burbank Centre [Member]	Mar. 31, 2013 127 West 25th Street [Member]	Mar. 31, 2013 180 N. Michigan [Member]	Mar. 31, 2013 Queensridge [Member]	Feb. 25, 2013 Concord Debt Holdings LLC [Member]	Feb. 25, 2013 CDH CDO LLC [Member]	Feb. 20, 2013 RE CDO Management LLC [Member]	Mar. 08, 2013 RE CDO Management LLC [Member]	Mar. 31, 2013 WRT Elad [Member]	Feb. 18, 2013 WRT Elad [Member]	Feb. 25, 2013 WRP Management LLC [Member]	Mar. 31, 2013 1515 Market Street [Member]	Feb. 01, 2013 1515 Market Street [Member]	Mar. 31, 2013 Andover, Massachusetts [Member]	Mar. 31, 2013 Recourse Secured Financings [Member]	Dec. 31, 2012 Recourse Secured Financings [Member]
Acquisition Disposition Leasing and Financing Activities (Textual) [Abstract]
Office building area, square foot				260,000
Mortgage Loan					$ 80,300,000															$ 70,000,000
LIBOR plus					14.25%
Pari passu participation interest in the loan						50.00%
Loan bears interest, description of variable rate basis	LIBOR plus 3%			0.50% LIBOR floor
Mortgage loan, LIBOR floor rate				0.50%
Interest rate					8.25%
Origination Fee (Amount)							205,000
Proceeds from sale of participation interest in loan					10,250,000
Credit allowed to borrower						100,000
Gain or loss recognized on the sale of the interest					0
Maturity date of loan																				Feb. 01, 2016
Increased outstanding principal amount																				71,629,000
Mortgage loans on real estate adjusted interest rate minimum																				7.50%
LIBOR plus																				6.50%
Increased loan balance through future funding advances																				6,000,000
Future advances																				500,000
Fee to be paid by the borrower																1,400,000	1,400,000
Additional increase in indirect future interest																6.00%	6.00%
Gain/loss recognized on payoff									0	0
Aggregate principal payments											10,117,000
Interest rate increase for each future advances																				0.10%
Percentage for participation																				40.00%
Payment to acquire indirect interest																			10,000
Acquired interest rate through indirect																				49.00%
Revenue																			1,861,000
Net Income																			496,000
Gross proceeds from sales																					12,000,000
Net proceeds																					11,425,000
Gain on sale of property																					2,775,000
Principal amount of the loan							20,500,000
Maturity date of loan				Jan. 23, 2015
Purchase price of acquired entity								9,000,000
Percentage of space of retail property leased								100.00%
Business acquisition cost of acquired entity face value								10,000,000
Proceeds from mortgage loans payable		743,000												2,750,000
Transfer Price of collateral management agreement														0
Tranche subordinated interests															6,240,000
Sale of interest													25,000
Trust received distributions															4,416,000
Equity interest Percentage													17.00%
Percentage of Trust Hold Interest Rate													49.67%
Percentage of the ownership												17.00%						100.00%
Carrying Value of Loans Receivable	130,212,000		211,250,000								28,976,000
Non-recourse secured financings																						$ 13,653,000	$ 23,770,000