Adoption of Accounting Standards Codification Topic 842, Leases - SOP (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Rental and related revenues									$ 469,698	$ 574,332	$ 568,380
Tenant recoveries									1,473	1,464	1,029
Total revenues	$ 103,567	$ 123,667	$ 123,690	$ 120,247	$ 141,775	$ 146,000	$ 145,549	$ 142,472	471,171	575,796	569,409
Costs and expenses:
Depreciation and amortization									165,555	244,624	247,914
Operating									3,720	3,729	3,247
General and administrative									22,058	23,907	20,690
Impairment charge									167,057	227,383
Interest									25,019
Total costs and expenses									383,409	499,643	271,851
Other income:
Gain on sales of real estate									10,583	39,140	(1,917)
Other income, net									282	70	953
Total other income, net									10,865	39,210	(964)
Income before income taxes and income from and impairment of equity method investment	(105,262)	58,693	83,799	61,397	(63,675)	79,634	76,271	23,133	98,627	115,363	296,594
Income tax expense									(17,482)	(798)	(765)
Income from equity method investment										34,510	60,469
Impairment of equity method investment										(35,882)	(63,255)
Net income (loss)	(104,730)	$ 53,520	$ 83,593	$ 48,762	(88,672)	$ 74,990	$ 89,908	$ 36,967	81,145	113,193	293,043
Comprehensive income (loss)									81,145	113,193	293,043
Straight-line rent receivables, net	3,296				95,259				3,296	95,259
Classified as DFL
Revenues:
Income from direct financing lease									442,278	572,835	598,629
Rental and related revenues									27,531	27,651	27,111
Tenant recoveries									1,473	1,464	1,029
Total revenues									471,282	601,950	626,769
Costs and expenses:
Depreciation and amortization									5,862	5,880	4,979
Operating									4,077	3,729	3,247
General and administrative									21,701	19,907	20,690
Impairment charge										1,295,504
Interest									25,019
Total costs and expenses									56,659	1,325,020	28,916
Other income:
Other income, net									282	70	953
Total other income, net									282	70	953
Income before income taxes and income from and impairment of equity method investment									414,905	(723,000)	598,806
Income tax expense									(17,482)	(798)	(765)
Income from equity method investment										50,723	53,175
Impairment of equity method investment										(45,895)	(35,913)
Net income (loss)									397,423	(718,970)	615,303
Comprehensive income (loss)									397,423	(718,970)	615,303
Adjustment
Other income:
Net income (loss)									(316,278)	832,163	(322,260)
Reported as Operating Lease
Revenues:
Rental and related revenues									469,698	574,332	568,380
Tenant recoveries									1,473	1,464	1,029
Total revenues									471,171	575,796	569,409
Costs and expenses:
Depreciation and amortization									165,555	244,624	247,914
Operating									3,720	3,729	3,247
General and administrative									22,058	23,907	20,690
Impairment charge									167,057	227,383
Interest									25,019
Total costs and expenses									383,409	499,643	271,851
Other income:
Gain on sales of real estate									10,583	39,140	(1,917)
Other income, net									282	70	953
Total other income, net									10,865	39,210	(964)
Income before income taxes and income from and impairment of equity method investment									98,627	115,363	296,594
Income tax expense									(17,482)	(798)	(765)
Income from equity method investment										34,510	60,469
Impairment of equity method investment										(35,882)	(63,255)
Net income (loss)									81,145	113,193	293,043
Comprehensive income (loss)									81,145	113,193	293,043
Straight-line rent receivables, net	3,296				95,259				3,296	95,259
ASU No. 2016 02, Leases (Topic 842) | Early Adoption | Adjustment
Revenues:
Income from direct financing lease									(442,278)	(572,835)	(598,629)
Rental and related revenues									442,167	546,681	541,269
Total revenues									(111)	(26,154)	(57,360)
Costs and expenses:
Depreciation and amortization									159,693	238,744	242,935
Operating									(357)
General and administrative									357	4,000
Impairment charge									167,057	(1,068,121)
Total costs and expenses									326,750	(825,377)	242,935
Other income:
Gain on sales of real estate									10,583	39,140	(1,917)
Total other income, net									10,583	39,140	(1,917)
Income before income taxes and income from and impairment of equity method investment									(316,278)	838,363	(302,212)
Income from equity method investment										(16,213)	7,294
Impairment of equity method investment										10,013	(27,342)
Comprehensive income (loss)									(316,278)	832,163	$ (322,260)
Straight-line rent receivables, net	$ 3,296				$ 95,259				$ 3,296	$ 95,259