Segment Information (Details) $ in Thousands		3 Months Ended		6 Months Ended
	Jul. 01, 2021	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) segment	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment				3
Revenue		$ 689,516	$ 723,292	$ 1,367,336	$ 1,472,737
Segment operating income		138,464	129,438	266,379	256,777
General and administrative expense (including non-cash stock-based compensation expense)		41,752	52,400	86,878	102,343
Facility lease expense		41,538	43,864	83,102	88,282
Depreciation and amortization		86,623	83,591	172,307	167,482
Asset impairment		2,599	2,078	11,674	12,755
Income (loss) from operations		(34,048)	(52,495)	(87,582)	(114,085)
Total assets		6,168,296		6,168,296		$ 6,410,467
Goodwill		27,321		27,321		27,321
Other operating income
Segment Reporting Information [Line Items]
Revenue		8,411	1,308	8,787	12,043
Independent Living
Segment Reporting Information [Line Items]
Goodwill		27,300		27,300		27,300
Independent Living | Other operating income
Segment Reporting Information [Line Items]
Revenue		1,159	111	1,161	1,475
Assisted Living and Memory Care | Other operating income
Segment Reporting Information [Line Items]
Revenue		6,412	629	6,768	5,733
CCRCs | Other operating income
Segment Reporting Information [Line Items]
Revenue		840	46	858	1,730
Health Care Services | HCA Healthcare, Inc. | Securities Purchase Agreement
Segment Reporting Information [Line Items]
Sale of stock, percentage of ownership sold in transaction (as a percent)	80.00%
Sale of stock, percentage of ownership after transaction (as a percent)	20.00%
Health Care Services | Other operating income
Segment Reporting Information [Line Items]
Revenue		0	522	0	3,105
Operating Segments | Independent Living
Segment Reporting Information [Line Items]
Revenue		126,737	118,116	251,143	238,262
Segment operating income		38,709	35,292	76,393	72,621
Total assets		1,310,044		1,310,044		1,349,341
Operating Segments | Assisted Living and Memory Care
Segment Reporting Information [Line Items]
Revenue		440,866	392,347	873,354	784,389
Segment operating income		87,588	77,062	164,451	148,495
Total assets		3,551,394		3,551,394		3,601,144
Operating Segments | CCRCs
Segment Reporting Information [Line Items]
Revenue		81,196	76,988	161,652	150,451
Segment operating income		8,838	8,673	18,877	16,281
Total assets		681,846		681,846		693,386
Operating Segments | Corporate and All Other
Segment Reporting Information [Line Items]
Revenue		40,717	48,006	81,187	122,366
Segment operating income		3,329	4,998	6,658	13,564
Total assets		625,012		625,012		$ 766,596
Operating Segments | Health Care Services
Segment Reporting Information [Line Items]
Revenue		0	87,835	0	177,269
Segment operating income		$ 0	$ 3,413	$ 0	$ 5,816