Supplemental Disclosure of Cash Flow Information - Supplemental Disclosure of Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental Cash Flow Information [Abstract]
Interest paid					$ 260,706	$ 294,758	$ 349,535
Income taxes paid, net of refunds					2,058	1,038	2,047
Net cash paid					225,473	213,887	333,647
Prepaid expenses and other assets, net					26,762	21,970	2,954
(Gain) loss on sale of assets, net	$ (216,660)	$ (9,833)	$ (23,322)	$ (43,431)	(293,246)	(19,273)	(7,218)
Loss on facility lease termination and modification, net	(13,197)	$ (2,337)	$ (146,467)	$ 0	(162,001)	(14,276)	(11,113)
Net cash paid					12,548	552	9,250
Additions to property, plant and equipment and leasehold intangibles, net
Supplemental Cash Flow Information [Abstract]
Property, plant and equipment and leasehold intangibles, net					220,810	221,476	300,113
Trade accounts payable					4,663	(7,589)	33,534
Net cash paid					225,473	213,887	333,647
Acquisition of assets, net of related payables and cash received
Supplemental Cash Flow Information [Abstract]
Property, plant and equipment and leasehold intangibles, net					237,563	0	19,457
Other intangible assets, net					(4,345)	5,196	(7,300)
Capital and financing lease obligations					36,120	0	0
Other liabilities					2,433	0	0
Net cash paid					271,771	5,196	12,157
Proceeds from sale of assets, net
Supplemental Cash Flow Information [Abstract]
Prepaid expenses and other assets, net					(4,950)	(17,072)	(4,543)
Assets held for sale					(197,111)	(20,952)	(289,452)
Property, plant and equipment and leasehold intangibles, net					(93,098)	(155,723)	0
Investments in unconsolidated ventures					(58,179)	(52,548)	0
Long-term debt					0	8,547	0
Capital and financing lease obligations					93,514	157,963	0
Other liabilities					1,139	(1,058)	3,281
Refundable entrance fees and deferred revenue					8,632	30,771	0
(Gain) loss on sale of assets, net					(249,754)	(19,273)	(7,218)
Loss on facility lease termination and modification, net					0	(1,162)	0
Net cash received					(499,807)	(70,507)	(297,932)
Lease termination and modification, net
Supplemental Cash Flow Information [Abstract]
Capital and financing lease obligations					58,099	0	0
Prepaid expenses and other assets, net					(2,804)	0	0
Property, plant and equipment and leasehold intangibles, net					(87,464)	0	0
(Gain) loss on sale of assets, net					(5,761)	0	0
Loss on facility lease termination and modification, net					(34,283)	0	0
Deferred liabilities					70,835	0	0
Net cash paid					67,188	0	0
Formation of the Blackstone Venture
Supplemental Cash Flow Information [Abstract]
Prepaid expenses and other assets, net					0	(8,173)	0
Deferred liabilities					0	7,504	0
Investments in unconsolidated ventures	$ 0				0	66,816	0
Property, plant and equipment and leasehold intangibles, net					0	(768,897)	0
Capital and financing lease obligations					0	879,959	0
Other liabilities					0	1,998	0
Net cash paid					$ 0	$ 179,207	$ 0