Supplemental Disclosure of Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Supplemental Cash Flow Information [Abstract]
Interest paid			$ 107,854	$ 124,647
Income taxes paid, net of refunds			1,388	1,916
Net cash paid			112,863	122,297
Operating lease right-of-use assets	$ 6,600		72,300
Loss (gain) on debt modification and extinguishment, net	(157)	$ (2,672)	19,024	(2,739)
Investments in unconsolidated ventures			(356)	(4,204)
Loss (gain) on sale of assets, net	(1,029)	2,846	371,810	2,144
Prepaid expenses and other assets, net			20,162	30,823
Loss (gain) on facility lease termination and modification, net	$ 0	$ 1,797	0	2,006	$ 0	$ 2,006
Additions to property, plant and equipment and leasehold improvements
Supplemental Cash Flow Information [Abstract]
Net cash paid			112,863	122,297
Trade accounts payable			10,040	(10,392)
Acquisition of communities from Healthpeak
Supplemental Cash Flow Information [Abstract]
Property, plant and equipment and leasehold intangibles, net			286,734	0
Operating lease right-of-use assets			(63,285)	0
Financing lease obligations			129,196	0
Operating lease obligations			74,335	0
Loss (gain) on debt modification and extinguishment, net			(19,731)	0
Net cash paid			407,249	0
Acquisition of assets, net of related payables and cash received
Supplemental Cash Flow Information [Abstract]
Property, plant and equipment and leasehold intangibles, net			179	0
Financing lease obligations			39,260	0
Net cash paid			39,439	0
Proceeds from sale of CCRC Venture, net:
Supplemental Cash Flow Information [Abstract]
Investments in unconsolidated ventures			(14,848)	0
Current portion of long-term debt			34,706	0
Other liabilities			60,748	0
Loss (gain) on sale of assets, net			(369,831)	0
Net cash received			(289,225)	0
Proceeds from sale of assets, net
Supplemental Cash Flow Information [Abstract]
Property, plant and equipment and leasehold intangibles, net			(938)	(688)
Investments in unconsolidated ventures			0	(156)
Other liabilities			(1,862)	(1,762)
Loss (gain) on sale of assets, net			(1,979)	(2,144)
Prepaid expenses and other assets, net			(1,261)	(5,798)
Assets held for sale			(5,274)	(41,882)
Net cash received			(11,314)	(52,430)
Assets designated as held for sale
Supplemental Cash Flow Information [Abstract]
Property, plant and equipment and leasehold intangibles, net			0	4,933
Prepaid expenses and other assets, net			0	(5)
Assets held for sale			0	(4,928)
Net			0	0
Healthpeak master lease modification:
Supplemental Cash Flow Information [Abstract]
Property, plant and equipment and leasehold intangibles, net			(57,462)	0
Operating lease right-of-use assets			88,044	0
Financing lease obligations			70,874	0
Operating lease obligations			(101,456)	0
Net			0	0
Noncash lease termination and modification, net
Supplemental Cash Flow Information [Abstract]
Property, plant and equipment and leasehold intangibles, net			13,548	(1,666)
Operating lease right-of-use assets			1,350	(5,009)
Financing lease obligations			(15,483)	0
Operating lease obligations			606	5,654
Other liabilities			(21)	(337)
Prepaid expenses and other assets, net			0	(648)
Loss (gain) on facility lease termination and modification, net			0	2,006
Net			0	0
Non-development | Additions to property, plant and equipment and leasehold improvements
Supplemental Cash Flow Information [Abstract]
Net cash paid			82,077	121,066
Development | Additions to property, plant and equipment and leasehold improvements
Supplemental Cash Flow Information [Abstract]
Net cash paid			6,823	10,623
Non-development - reimbursable | Additions to property, plant and equipment and leasehold improvements
Supplemental Cash Flow Information [Abstract]
Net cash paid			$ 13,923	$ 1,000