Real Estate and Loans Receivable - Loans - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended
	Mar. 01, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 01, 2012	Dec. 31, 2011
Significant Acquisitions and Disposals [Line Items]
Existing mortgage loan		$ 397,500,000	$ 388,650,000	$ 368,650,000		$ 165,000,000
Amount of convertible note converted into equity interest	1,600,000
Convertible note	5,000,000				5,000,000
Percentage of equity shares from convertible debt	9.90%	15.10%
Remaining convertible debt after conversion of part of debt		3,400,000
Ernest Transaction and Other Acquisitions [Member]
Significant Acquisitions and Disposals [Line Items]
Existing mortgage loan		97,500,000
Median Transaction [Member]
Significant Acquisitions and Disposals [Line Items]
Existing mortgage loan		$ 422,500,000