Loans Receivable - Summary of Trust's Loans Receivable (Detail) (USD $)								12 Months Ended			12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended			12 Months Ended			12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Whole Loan [Member]	Dec. 31, 2012 Whole Loan [Member]	Dec. 31, 2013 B Note [Member]	Dec. 31, 2012 B Note [Member]	Dec. 31, 2013 Corporate Loan [Member]	Dec. 31, 2013 Mezzanine [Member]	Dec. 31, 2012 Mezzanine [Member]	Dec. 31, 2013 Hotel Wales [Member] Whole Loan [Member]	Dec. 31, 2012 Hotel Wales [Member] Whole Loan [Member]	Dec. 31, 2013 The Shops at Wailea [Member] B Note [Member]	Dec. 31, 2012 The Shops at Wailea [Member] B Note [Member]	Dec. 31, 2013 Legacy Orchard [Member] Corporate Loan [Member]	Dec. 31, 2012 Legacy Orchard [Member] Corporate Loan [Member]	Dec. 31, 2013 Queensridge [Member] Whole Loan [Member]	Dec. 31, 2012 Queensridge [Member] Whole Loan [Member]	Dec. 31, 2013 San Marbeya [Member] Whole Loan [Member]	Dec. 31, 2012 San Marbeya [Member] Whole Loan [Member]	Dec. 31, 2013 Churchill [Member] Whole Loan [Member]	Dec. 31, 2012 Churchill [Member] Whole Loan [Member]	Dec. 31, 2012 1515 Market [Member] Whole Loan [Member]	Dec. 31, 2013 Playa Vista Waters Edge [Member] Mezzanine [Member]	Dec. 31, 2013 Rockwell [Member] Mezzanine [Member]	Dec. 31, 2012 Rockwell [Member] Mezzanine [Member]	Dec. 31, 2013 500-512 7th Ave [Member] B Note [Member]	Dec. 31, 2012 500-512 7th Ave [Member] B Note [Member]	Dec. 31, 2013 Pinnacle II [Member] B Note [Member]	Dec. 31, 2012 Pinnacle II [Member] B Note [Member]	Dec. 31, 2013 Popiu Shopping Village [Member] B Note [Member]	Dec. 31, 2012 Popiu Shopping Village [Member] B Note [Member]	Dec. 31, 2013 Wellington Tower [Member] Mezzanine [Member]	Dec. 31, 2012 Wellington Tower [Member] Mezzanine [Member]	Dec. 31, 2013 Mentor Building [Member] Whole Loan [Member]	Dec. 31, 2012 Mentor Building [Member] Whole Loan [Member]	Dec. 31, 2013 Renaissance Walk [Member] Mezzanine [Member]	Dec. 31, 2012 Renaissance Walk [Member] Mezzanine [Member]	Dec. 31, 2013 Fenway Shea [Member] Whole Loan [Member]	Dec. 31, 2012 Fenway Shea [Member] Whole Loan [Member]	Dec. 31, 2013 127 West 25th Street [Member] Mezzanine [Member]	Dec. 31, 2012 127 West 25th Street [Member] Mezzanine [Member]	Dec. 31, 2013 180 N. Michigan [Member] Mezzanine [Member]	Dec. 31, 2012 180 N. Michigan [Member] Mezzanine [Member]	Dec. 31, 2013 The Disney Building [Member] B Note [Member]	Dec. 31, 2012 The Disney Building [Member] B Note [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage Loans, Stated Interest Rate, Variable Rate Basis											LIBOR + 4.0		6.15		15.0		LIBOR + 11.5		5.88		LIBOR + 3.75			LIBOR + 14.25	12.0		7.19		6.31		6.62		6.79		10.0		-		-		-		-		-
Interest rate on mortgage loans								15.00%			4.00%		6.15%		15.00%		11.50%		5.88%		3.75%			14.25%	12.00%		7.19%		6.31%		6.62%		6.79%		10.00%
Loans receivable, net	$ 101,100,000	$ 211,250,000	$ 114,333,000	$ 64,534,000	$ 160,288,000	$ 23,248,000	$ 31,028,000		$ 13,318,000	$ 19,934,000	$ 20,101,000	$ 20,101,000	$ 6,292,000	$ 5,376,000	$ 9,750,000	$ 9,750,000	$ 2,942,000	$ 39,170,000	$ 28,546,000	$ 27,149,000	$ 683,000	$ 683,000	$ 58,650,000	$ 10,327,000		$ 323,000	$ 10,250,000	$ 10,009,000	$ 4,648,000	$ 4,652,000	$ 2,058,000	$ 1,948,000	$ 2,991,000	$ 2,687,000	$ 2,512,000	$ 2,512,000		$ 3,000,000		$ 2,273,000		$ 8,687,000		$ 5,237,000		$ 9,043,000
Contractual Maturity Date								Oct. 31, 2014			Oct. 05, 2014		Oct. 06, 2014		Oct. 31, 2014		Nov. 15, 2014		Jan. 01, 2015		Jun. 01, 2015			Jan. 23, 2015	May 01, 2016		Jul. 11, 2016		Sep. 06, 2016		Jan. 06, 2017		Jul. 11, 2017		Sep. 10, 2017