Loans Receivable - Additional Information (Detail)		1 Months Ended	3 Months Ended	6 Months Ended		12 Months Ended
	Feb. 05, 2015 USD ($)	Aug. 31, 2013 USD ($)	Jun. 30, 2014 USD ($) Loans	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($) Loans	Dec. 31, 2014 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, accrued interest				$ 27,000		$ 218,000
Weighted average coupon rate on loans receivable				8.04%		10.55%
Weighted average yield to maturity				13.73%		12.78%
Provision for loan loss			$ 0		$ 0
Number of non-performing loans with past due payments | Loans			1		1
Period for the return of assets				2 years
Annual interest rate		15.00%
Edens Center and Norridge Commons [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal payment of loans	$ 15,275,000
Outstanding principal balance on loan receivable				$ 97,000
Loan participation interest IRR percentage				14.50%
Loan participation interest IRR percentage after initial term				15.50%
Loan participation interest percentage				30.00%
Loan participation interest percentage after initial term				40.00%
Minimum value of properties for entitlement to loan participation interest				$ 115,000,000
Description of Trust's participation interest in loan				Upon satisfaction of the loan, the Trust is entitled to a participation interest equal to the greater of (i) a 14.5% internal rate of return ("IRR") (increasing to a 15.5% IRR after March 9, 2017) and (ii) 30% (increasing to 40% after March 9, 2017 and 50% after March 9, 2018) of the value of both of the properties which collateralized the loan in excess of $115,000,000.
Loan participation interest percentage after initial term				50.00%
Lender LP [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured financing receivable		$ 30,000,000
Elad Canada Ltd [Member] | Lender LP [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Rate of interest for acquisition		50.00%
Secured Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest income			$ 951,000		$ 1,892,000