Preferred Equity Investments (Details) (USD $)	0 Months Ended	1 Months Ended		12 Months Ended					1 Months Ended	12 Months Ended			1 Months Ended	12 Months Ended			1 Months Ended
	Aug. 06, 2012	Jan. 31, 2012	Jan. 14, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Vintage Housing Venture [Member]	Dec. 31, 2012 Vintage Housing Venture [Member]	Jan. 31, 2012 Marc Realty [Member]	Dec. 31, 2012 Marc Realty [Member]	Dec. 31, 2011 Marc Realty [Member]	Dec. 31, 2010 Marc Realty [Member]	Dec. 31, 2012 WRT-Fenway Wateridge LLC [Member]	Dec. 31, 2012 WRT-Fenway Wateridge LLC [Member]	Dec. 21, 2012 WRT-Fenway Wateridge LLC [Member]	Dec. 31, 2012 VHH LLC [Member]	Jan. 31, 2012 180 North Michigan [Member]
Schedule of Equity Method Investments [Line Items]
Preferred equity investments				$ 12,250,000	$ 5,520,000								$ 6,000,000	$ 6,000,000	$ 6,000,000	$ 4,750,000
Priority return from investment													12.00%	12.00%	12.00%
Percentage paid from operating cash flow													8.00%	8.00%	8.00%
Percentage deferred from investment													4.00%	4.00%
Percentage acquired in member interest								12.00%								12.00%
Loan Amount								1,500,000
Interest of loan	9.00%		6.40%	3.95%			12.00%
Due Payment							0	0
Equity (loss) income				14,678,000	(12,712,000)	(2,007,000)				33,000	338,000,000	338,000,000
Preferred equity investment				3,923,000	7,843,000				(3,923,000)								3,923,000,000
Loan receivable to an equity investment		$ 2,938,000,000		$ (2,938,000)					$ (2,938,000)