Loans Receivable - Summary of Trust's Loans Receivable (Detail) (USD $) In Thousands, unless otherwise specified	1 Months Ended	6 Months Ended
	Jan. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, net		$ 113,308	$ 211,250
Hotel Wales [Member] | Whole Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		LIBOR + 4.0%
Interest rate on mortgage loans		4.00%
Loans receivable, net		20,097	20,101
Contractual Maturity Date		Oct. 05, 2013
Renaissance Walk [Member] | Mezzanine [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		LIBOR + 12.0%
Interest rate on mortgage loans		12.00%
Loans receivable, net		3,000	3,000
Contractual Maturity Date		Jan. 01, 2014
Playa Vista [Member] | Mezzanine [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		LIBOR + 14.25
Interest rate on mortgage loans		14.25%
Loans receivable, net		10,322	0
Contractual Maturity Date	Jan. 23, 2015	Jan. 23, 2015
Queensridge [Member] | Whole Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		LIBOR + 11.5%
Interest rate on mortgage loans		11.50%
Loans receivable, net		13,863	39,170
Contractual Maturity Date		Nov. 15, 2014
The Shops at Wailea [Member] | B Note [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		6.15
Interest rate on mortgage loans		6.15%
Loans receivable, net		5,796	5,376
Contractual Maturity Date		Oct. 06, 2014
Legacy Orchard [Member] | Corporate Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		15.0
Interest rate on mortgage loans		15.00%
Loans receivable, net		9,750	9,750
Contractual Maturity Date		Oct. 31, 2014
San Marbeya [Member] | Whole Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		5.88
Interest rate on mortgage loans		5.88%
Loans receivable, net		27,502	27,149
Contractual Maturity Date		Jan. 01, 2015
Churchill [Member] | Whole Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		LIBOR + 3.75%
Interest rate on mortgage loans		3.75%
Loans receivable, net		683	683
Contractual Maturity Date		Jun. 01, 2015
Rockwell [Member] | Mezzanine [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		12.0
Interest rate on mortgage loans		12.00%
Loans receivable, net		364	323
Contractual Maturity Date		May 01, 2016
500-512 7th Avenue [Member] | B Note [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		7.19
Interest rate on mortgage loans		7.19%
Loans receivable, net		10,019	10,009
Contractual Maturity Date		Jul. 11, 2016
Pinnacle II [Member] | B Note [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		6.31
Interest rate on mortgage loans		6.31%
Loans receivable, net		4,648	4,652
Contractual Maturity Date		Sep. 06, 2016
Poipu Shopping Village [Member] | B Note [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		6.62
Interest rate on mortgage loans		6.62%
Loans receivable, net		1,999	1,948
Contractual Maturity Date		Jan. 06, 2017
Wellington Tower [Member] | Mezzanine [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		6.79
Interest rate on mortgage loans		6.79%
Loans receivable, net		2,754	2,687
Contractual Maturity Date		Jul. 11, 2017
Mentor Building [Member] | Whole Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		10.0
Interest rate on mortgage loans		10.00%
Loans receivable, net		2,511	2,512
Contractual Maturity Date		Sep. 10, 2017
1515 Market [Member] | Whole Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		-6
Loans receivable, net			58,650
127 West 25th Street [Member] | Mezzanine [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		-
Loans receivable, net			8,687
180 N. Michigan [Member] | Mezzanine [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		-
Loans receivable, net			5,237
Fenway Shea [Member] | Whole Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		-
Loans receivable, net			2,273
The Disney Building [Member] | B Note [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis		-
Loans receivable, net			$ 9,043