Loans Receivable - Additional Information (Detail) (USD $)	3 Months Ended	6 Months Ended	12 Months Ended	1 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Feb. 28, 2013 Playa Vista [Member] Mezzanine [Member]	Jan. 31, 2013 Playa Vista [Member] Mezzanine [Member] sqft	Jun. 30, 2013 Playa Vista [Member] Mezzanine [Member]	Jan. 24, 2013 Playa Vista [Member] Mezzanine [Member]	Jun. 30, 2013 Recourse Secured Financings [Member]	Dec. 31, 2012 Recourse Secured Financings [Member]
Mortgage Loans on Real Estate [Line Items]
Loans receivable accrued interest	$ 640,000	$ 640,000	$ 1,016,000
Cumulative accretion of loans receivable	4,004,000	4,004,000	2,527,000
Loans receivable, exclusive of interest receivable	5,861,000	5,861,000	9,865,000
Weighted average coupon rate on loans receivable		7.09%	7.65%
Weighted average yield to maturity		11.86%	11.43%
Principal amount of the loan							20,500,000
Office building area, square foot					260,000
Mortgage Loan						80,300,000
LIBOR plus						14.25%
Pari passu participation interest in the loan				50.00%
Loan bears interest, description of variable rate basis		LIBOR plus 3%			0.5% 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
Maturity date of loan					Jan. 23, 2015	Jan. 23, 2015
Gain or loss recognized on the sale of the interest						0
Non recourse secured financings	29,150,000	29,150,000	29,150,000
Secured financings	29,150,000	29,150,000	52,920,000					23,770,000,000	23,770,000,000
Non performing loans	0	0	0
Past due payments	0	0	0
Provision for loan loss	$ 0	$ 0