Supplemental Disclosure of Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Supplemental Cash Flow Information [Abstract]
Interest paid			$ 133,000	$ 155,389
Income taxes paid, net of refunds			1,421	1,876
Net cash paid			120,458	89,570
Prepaid expenses and other assets			1,878	18,979
(Gain) loss on sale of assets, net	$ (23,322)	$ 547	(66,753)	1,150
Loss on facility lease termination and modification	146,467	6,368	146,467	6,368
Net cash paid			10,548	552
Additions to property, plant and equipment and leasehold intangibles, net
Supplemental Cash Flow Information [Abstract]
Property, plant and equipment and leasehold intangibles, net			105,266	91,014
Accounts payable			15,192	(1,444)
Net cash paid			120,458	89,570
Acquisition of assets, net of related payables
Supplemental Cash Flow Information [Abstract]
Property, plant and equipment and leasehold intangibles, net			237,563	0
Other intangible assets, net			(4,796)	400
Capital and financing lease obligations			36,120	0
Other liabilities			2,433	0
Net cash paid			271,320	400
Proceeds from sale of assets, net
Supplemental Cash Flow Information [Abstract]
Prepaid expenses and other assets			(1,991)	(13,954)
Assets held for sale			(18,758)	(20,952)
Property, plant and equipment and leasehold intangibles, net			(87,864)	(11,598)
Investments in unconsolidated ventures			(58,179)	(26,301)
Long-term debt			0	7,552
Capital and financing lease obligations			93,514	0
Refundable entrance fees and deferred revenue			8,345	30,771
Other liabilities			789	39
(Gain) loss on sale of assets, net			(66,753)	1,150
Loss on facility lease termination and modification			0	1,162
Net cash received			(130,897)	(34,455)
Lease termination and modification, net
Supplemental Cash Flow Information [Abstract]
Prepaid expenses and other assets			(2,000)	0
Property, plant and equipment and leasehold intangibles, net			(52,920)	0
Capital and financing lease obligations			21,898	0
Loss on facility lease termination and modification			22,260	0
Deferred liabilities			67,950	0
Net cash paid			57,188	0
Formation of the Blackstone Venture
Supplemental Cash Flow Information [Abstract]
Prepaid expenses and other assets			0	(8,173)
Investments in unconsolidated ventures	$ 0	$ 66,816	0	66,816
Capital and financing lease obligations			0	879,959
Deferred liabilities			0	7,504
Other liabilities			0	1,998
Property, plant and equipment and leasehold intangibles, net			0	(768,897)
Net cash paid			0	179,207
Assets designated as held for sale
Supplemental Cash Flow Information [Abstract]
Prepaid expenses and other assets			0	(106)
Assets held for sale			(58,445)	14,122
Property, plant and equipment and leasehold intangibles, net			(58,445)	14,016
Net			0	0
Lease termination and modification, net
Supplemental Cash Flow Information [Abstract]
Prepaid expenses and other assets			2,813	0
Property, plant and equipment and leasehold intangibles, net			(2,959)	0
Capital and financing lease obligations			2,375	0
Other liabilities			326	0
Loss on facility lease termination and modification			124,207	0
Deferred liabilities			(122,304)	0
Net			$ 0	$ 0