Organization, Basis of Presentation, Real Estate and Depreciation, Financial Instruments, Restricted Cash / Investments, and Recent Accounting Standards - Recent Accounting Standards (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
RECENT ACCOUNTING STANDARDS
Assets	$ (188,583,000)		$ (188,583,000)		$ (191,660,000)
Liabilities	(40,099,000)		(40,099,000)		(40,801,000)
Change to net loss	$ (257,000)	$ (569,000)	(978,000)	$ (1,286,000)
ASU No. 2015-03 | Pro forma adjustment
RECENT ACCOUNTING STANDARDS
Assets					171,000
Liabilities					171,000
Change to net loss			$ 0		$ 0