Equity Investments - Activity of the Trust's Equity Investments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Schedule of Equity Method Investments [Line Items]
Beginning Balance			$ 149,085
Contributions			46,159
Equity Income (loss)	4,178	4,524	10,372	12,393
Distributions			(8,878)
Sales Price			(200)
Ending Balance	196,538		196,538
Sealy [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			7,635
Contributions			0
Equity Income (loss)			(1,926)
Distributions			0
Sales Price			0
Ending Balance	5,709		5,709
Vintage Housing Holdings, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			34,153
Contributions			450
Equity Income (loss)			3,679
Distributions			(3,180)
Sales Price			0
Ending Balance	35,102		35,102
WRT-Elad One South State Equity LP [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			0
Contributions			0
Equity Income (loss)			10
Distributions			(10)
Sales Price			0
Ending Balance	0		0
WRT One South State Lender LP [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			23,661
Contributions			10
Equity Income (loss)			2,499
Distributions			(1,961)
Sales Price			0
Ending Balance	24,209		24,209
WRT-Fenway Wateridge LLC [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			1,898
Contributions			91
Equity Income (loss)			106
Distributions			0
Sales Price			0
Ending Balance	2,095		2,095
701 7th WRT Investors LLC [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			55,259
Contributions			45,338
Equity Income (loss)			3,497
Distributions			(368)
Sales Price			0
Ending Balance	103,726		103,726
WRT-Stamford LLC [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			9,064
Contributions			0
Equity Income (loss)			461
Distributions			(171)
Sales Price			0
Ending Balance	9,354		9,354
10 Metrotech Loan LLC [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			11
Contributions			0
Equity Income (loss)			0
Distributions			0
Sales Price			0
Ending Balance	11		11
RE CDO Management LLC [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			992
Contributions			0
Equity Income (loss)			6
Distributions			(31)
Sales Price			0
Ending Balance	967		967
Concord Debt Holdings LLC [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			0
Contributions			0
Equity Income (loss)			515
Distributions			(515)
Sales Price			0
Ending Balance	0		0
CDH CDO LLC [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			0
Contributions			0
Equity Income (loss)			984
Distributions			(984)
Sales Price			0
Ending Balance	0		0
Concord Debt Holdings LLC (1) [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			966
Contributions			0
Equity Income (loss)			88
Distributions			(515)
Sales Price			0
Ending Balance	539		539
CDH CDO LLC (1) [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			4,215
Contributions			0
Equity Income (loss)			1,247
Distributions			(984)
Sales Price			0
Ending Balance	4,478		4,478
Mentor Retail LLC [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			635
Contributions			0
Equity Income (loss)			37
Distributions			(90)
Sales Price			0
Ending Balance	582		582
Marc Realty [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			6,751
Contributions			0
Equity Income (loss)			(755)
Distributions			0
Sales Price			(200)
Ending Balance	5,796		5,796
WRT - ROIC Lakeside Eagle LLC [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			0
Contributions			20
Equity Income (loss)			(19)
Distributions			0
Sales Price			0
Ending Balance	1		1
Atrium Mall LLC [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			3,845
Contributions			0
Equity Income (loss)			(56)
Distributions			(69)
Sales Price			0
Ending Balance	3,720		3,720
Edens Plaza Associates [Member]
Schedule of Equity Method Investments [Line Items]
Beginning Balance			0
Contributions			250
Equity Income (loss)			(1)
Distributions			0
Sales Price			0
Ending Balance	$ 249		$ 249