Summary of Significant Accounting Policies (Detail 3) (USD $)	12 Months Ended
	Dec. 31, 2014 item	Dec. 31, 2013	Dec. 31, 2012
Real estate properties
Number of investment properties classified as held for sale	8
Income from discontinued operations
Gain on sales of real estate	$ 2,883,000	$ 64,743,000	$ 9,873,000
Rental revenue	112,000	5,475,000	14,615,000
Tenant reimbursements	1,000	146,000	379,000
Other revenue		419,000	282,000
Depreciation and amortization		(1,569,000)	(3,724,000)
Property expenses (including reimbursable)	(184,000)	(916,000)	(2,529,000)
Provisions for impairment	(510,000)	(2,738,000)	(1,500,000)
Crest's income (loss) from discontinued operations	498,000	110,000	(139,000)
Income from discontinued operations	2,800,000	65,670,000	17,257,000
Per common share, basic and diluted (in dollars per share)	$ 0.01	$ 0.34	$ 0.13
Revenue Recognition and Accounts Receivable
Allowance for Doubtful Accounts Receivable	765,000	498,000
Other Real Estate Revenue	$ 2,930,000	$ 7,047,000	$ 2,942,000