Equity Investments - Summary Financial Information of Income Statement for Unconsolidated Subsidiaries (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statements
Interest, dividends and discount accretion									$ 18,455,000	$ 21,123,000	$ 25,458,000
Revenue
Total revenue	23,227,000	18,255,000	19,040,000	19,036,000	17,552,000	15,204,000	16,753,000	15,827,000	79,558,000	65,336,000	61,306,000
Expenses
General and administrative									4,363,000	3,529,000	3,527,000
Other Income and Expense
Other Income									24,033,000	23,439,000	7,475,000
Gain on sale of assets									11,005,000	945,000	392,000
WRT-One South State Lender LP [Member]
Income Statements
Expenses									86,000	127,000
Income from continuing operations									8,420,000	7,251,000
Revenue
Interest Income									8,506,000	7,378,000
Management Fee Income
Total revenue									8,506,000	7,378,000
Expenses
General and administrative									86,000	127,000
Other expenses
Total expense									86,000	127,000
Other Income and Expense
Other Income
Income from continuing operations									8,420,000	7,251,000
RE CDO Management LLC [Member]
Income Statements
Expenses									1,749,000	483,000	231,000
Income from continuing operations									7,417,000	135,000	93,000
Revenue
Interest Income
Management Fee Income									226,000	618,000	324,000
Total revenue									226,000	618,000	324,000
Expenses
General and administrative									290,000	354,000	164,000
Other expenses									1,459,000	129,000	67,000
Total expense									1,749,000	483,000	231,000
Other Income and Expense
Gain on sale of assets									8,940,000
Income from continuing operations									7,417,000	135,000	93,000
Unconsolidated Subsidiaries [Member]
Income Statements
Rental Revenue									57,890,000	70,686,000	54,600,000
Interest, dividends and discount accretion									14,538,000	6,513,000	3,745,000
Expenses									43,672,000	68,286,000	59,190,000
Income from continuing operations									28,756,000	8,913,000	(845,000)
Trust's share of net income									16,679,000	6,472,000	(35,000)
Expenses
Total expense									43,672,000	68,286,000	59,190,000
Other Income and Expense
Income from continuing operations									$ 28,756,000	$ 8,913,000	$ (845,000)