Segment Information - Reconciliation of Consolidated Net Income to Consolidated NOI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting [Abstract]
Net income	$ 19,046	$ 7,884	$ 48,015	$ 52,871
Plus:
Interest expense	19,732	20,814	61,473	64,334
Interest expense - amortization of deferred financing costs	577	645	1,807	2,063
Interest expense - financing obligation	0	156	0	679
Depreciation and amortization	42,429	46,956	132,584	142,736
General and administrative expenses	5,813	5,515	21,797	20,711
Equity in loss of Real Estate Ventures	5,723	7,254	5,387	9,323
Provision for impairment	0	0	3,057	13,069
Loss on early extinguishment of debt	0	0	0	66,590
Less:
Interest income	79	291	635	970
Income tax benefit	793	0	1,032	0
Net gain (loss) on disposition of real estate	0	(104)	8,411	114,625
Net gain on sale of undepreciated real estate	953	188	953	188
Net gain on Real Estate Venture transactions	13,758	10,472	28,340	19,529
Consolidated net operating income	$ 77,737	$ 78,377	$ 234,749	$ 237,064