Segment Information - Reconciliation of Consolidated Net Income (Loss) to Consolidated NOI (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting [Abstract]
Net income (loss)	$ 7,698	$ (1,323)	$ 28,969	$ 44,987
Plus:
Interest expense	20,304	19,829	41,741	43,520
Interest expense - amortization of deferred financing costs	596	644	1,230	1,418
Interest expense - financing obligation	0	242	0	523
Depreciation and amortization	44,263	46,907	90,155	95,780
General and administrative expenses	6,320	6,076	15,745	15,196
Equity in (income) loss of Real Estate Ventures	(1,084)	1,666	(336)	2,069
Provision for impairment	327	5,679	3,057	13,069
Loss on early extinguishment of debt	0	0	0	66,590
Less:
Interest income	163	359	556	679
Net gain (loss) on disposition of real estate	1,088	(727)	8,411	114,729
Net gain on Real Estate Venture transactions	0	3,128	14,582	9,057
Consolidated net operating income	$ 77,173	$ 76,960	$ 157,012	$ 158,687