Investments in Real Estate Entities - Financial Position and Operating Results (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Assets:
Real estate, net	$ 699,440		$ 699,440		$ 954,493
Other assets	46,168		46,168		49,519
Total assets	745,608		745,608		1,004,012
Liabilities and partners' capital:
Mortgage notes payable and credit facility	525,170		525,170		689,573
Other liabilities	13,446		13,446		16,537
Partners' capital	206,992		206,992		297,902
Total liabilities and partners' capital	745,608		745,608		$ 1,004,012
Combined summary of the operating results of the accounted for using the equity method
Rental and other income	24,568	$ 30,771	79,999	$ 101,534
Operating and other expenses	(9,378)	(12,069)	(30,386)	(39,206)
Gain on sale of communities	107,067	0	136,514	180,256
Interest expense, net	(7,867)	(7,919)	(21,415)	(37,857)
Depreciation expense	(5,938)	(8,081)	(20,059)	(26,027)
Net income	108,452	2,702	144,653	178,700
Loss on extinguishment of debt, net	0	$ 0	24,162	2,461
Funds
Combined summary of the operating results of the accounted for using the equity method
Loss on extinguishment of debt, net	$ (1,601)		$ (1,591)	$ (12,321)