Equity Investments - Trust's Nominal Ownership Percentages in its Equity Investments (Detail)	Mar. 31, 2016	Dec. 31, 2015
WRT One South State Lender LP [Member] | Elad Canada Ltd [Member]
Schedule of Equity Method Investments [Line Items]
Nominal % Ownership	50.00%	50.00%
WRT-Elad One South State Equity LP [Member] | Elad Canada Ltd [Member]
Schedule of Equity Method Investments [Line Items]
Nominal % Ownership	50.00%	50.00%
RE CDO Management LLC [Member] | Atrium Holding [Member]
Schedule of Equity Method Investments [Line Items]
Nominal % Ownership	50.00%	50.00%
Mentor Retail LLC [Member] | Freed [Member]
Schedule of Equity Method Investments [Line Items]
Nominal % Ownership	49.90%	49.90%
Concord Debt Holdings LLC [Member] | Inland [Member]
Schedule of Equity Method Investments [Line Items]
Nominal % Ownership	66.60%	66.60%
CDH CDO LLC [Member] | Inland [Member]
Schedule of Equity Method Investments [Line Items]
Nominal % Ownership	49.60%	49.60%
Atrium Mall LLC [Member] | Marc Realty [Member]
Schedule of Equity Method Investments [Line Items]
Nominal % Ownership	50.00%	50.00%
701 Seventh WRT Investor LLC [Member] | New Valley/Witkoff [Member]
Schedule of Equity Method Investments [Line Items]
Nominal % Ownership	81.00%	81.00%
RS Summit Pointe [Member] | RS Summit Pointe Apartments LLC [Member]
Schedule of Equity Method Investments [Line Items]
Nominal % Ownership	80.00%	80.00%
446 High Line LLC [Member] | Serure CB High Line [Member]
Schedule of Equity Method Investments [Line Items]
Nominal % Ownership	84.99%	83.60%