Segment Information (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) segment	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			5
Revenue	$ 865,909	$ 1,019,457			$ 1,880,048	$ 2,061,501
Segment operating income	158,364	227,066			461,304	466,194
General and administrative expense (including non-cash stock-based compensation expense)	52,518	57,576	$ 107,113	$ 113,887	107,113	113,887
Facility lease expense	62,379	67,689	126,860	136,357	126,860	136,357
Depreciation and amortization	93,154	94,024	183,892	190,912	183,892	190,912
Asset impairment	10,290	3,769	88,516	4,160	88,516	4,160
Loss (gain) on facility lease termination and modification, net	0	1,797	0	2,006	0	2,006
Income (loss) from operations	(59,977)	2,211	(45,077)	$ 18,872	(45,077)	18,872
Total assets	7,424,543		7,424,543		7,194,433
Operating Segments | Independent Living
Segment Reporting Information [Line Items]
Revenue	130,278	135,951			266,140	271,645
Segment operating income	41,038	51,459			92,452	104,335
Asset impairment	0	0			31,317	0
Total assets	1,510,783		1,510,783		1,441,652
Operating Segments | Assisted Living and Memory Care
Segment Reporting Information [Line Items]
Revenue	432,308	450,225			889,787	908,751
Segment operating income	87,708	133,144			219,709	273,843
Asset impairment	10,290	1,180			43,088	1,537
Total assets	4,043,817		4,043,817		4,157,610
Operating Segments | CCRCs
Segment Reporting Information [Line Items]
Revenue	88,571	101,253			183,118	204,980
Segment operating income	13,850	17,847			33,781	39,484
Asset impairment	0	0			12,173	0
Total assets	792,989		792,989		742,809
Operating Segments | Health Care Services
Segment Reporting Information [Line Items]
Revenue	107,165	114,434			201,984	225,966
Segment operating income	9,692	9,167			571	17,340
Asset impairment	0	0			0	0
Total assets	248,702		248,702		256,715
Operating Segments | Management Services
Segment Reporting Information [Line Items]
Revenue	107,587	217,594			339,019	450,159
Segment operating income	6,076	15,449			114,791	31,192
Asset impairment	0	$ 2,589			1,938	$ 2,623
Total assets	828,252		$ 828,252		$ 595,647
CARES Act | CCRCs
Segment Reporting Information [Line Items]
Cash made available for Emergency Fund	9,700
CARES Act | Health Care Services
Segment Reporting Information [Line Items]
Cash made available for Emergency Fund	$ 17,000