Discontinued Operations and Dispositions of Real Estate - Schedule of Results of Discontinued Operations (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation and amortization		$ 0	$ (4,890,000)	$ (5,880,000)
Impairments		0	0	(1,341,399,000)
Income tax benefit (expense)	$ (53,000,000)	$ 0	(48,181,000)	(796,000)
QCP | Spinoff
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Rental and related revenues			22,971,000	27,651,000
Tenant recoveries			1,233,000	1,464,000
Income from direct financing leases			384,752,000	572,835,000
Total revenues			408,956,000	601,950,000
Depreciation and amortization			(4,892,000)	(5,880,000)
Operating			(3,367,000)	(3,697,000)
General and administrative			(67,000)	(57,000)
Transaction costs			(86,765,000)	0
Impairments			0	(1,295,504,000)
Other income (expense), net			71,000	70,000
Income (loss) before income taxes and income from impairments of equity method investments			313,936,000	(703,118,000)
Income tax benefit (expense)			(48,181,000)	(796,000)
Income from equity method investment			0	50,723,000
Impairments of equity method investment			0	(45,895,000)
Total discontinued operations			$ 265,755,000	$ (699,086,000)