Segment Information (Details) $ in Thousands		3 Months Ended		9 Months Ended
	Jul. 01, 2021	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) segment	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment				3
Revenue		$ 757,458	$ 641,654	$ 2,124,794	$ 2,114,391
Segment operating income		194,464	123,382	460,843	380,159
General and administrative expense (including non-cash stock-based compensation expense)		41,331	43,812	128,209	146,155
Facility lease expense		41,317	43,226	124,419	131,508
Depreciation and amortization		86,922	84,560	259,229	252,042
Asset impairment		5,688	639	17,362	13,394
Income (loss) from operations		19,206	(48,855)	(68,376)	(162,940)
Total assets		6,093,953		6,093,953		$ 6,410,467
Goodwill		27,321		27,321		27,321
Other operating income
Segment Reporting Information [Line Items]
Revenue		66,759	89	75,546	12,132
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		9,520	9	10,681	1,484
Assisted Living and Memory Care | Other operating income
Segment Reporting Information [Line Items]
Revenue		49,721	75	56,489	5,808
CCRCs | Other operating income
Segment Reporting Information [Line Items]
Revenue		7,518	5	8,376	1,735
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	0	0	3,105
Operating Segments | Independent Living
Segment Reporting Information [Line Items]
Revenue		137,626	119,593	388,769	357,855
Segment operating income		46,395	36,733	122,788	109,354
Total assets		1,297,172		1,297,172		1,349,341
Operating Segments | Assisted Living and Memory Care
Segment Reporting Information [Line Items]
Revenue		491,818	402,696	1,365,172	1,187,085
Segment operating income		130,039	75,324	294,490	223,819
Total assets		3,527,339		3,527,339		3,601,144
Operating Segments | CCRCs
Segment Reporting Information [Line Items]
Revenue		87,563	77,895	249,215	228,346
Segment operating income		15,063	7,704	33,940	23,985
Total assets		674,449		674,449		693,386
Operating Segments | Corporate and All Other
Segment Reporting Information [Line Items]
Revenue		40,451	41,470	121,638	163,836
Segment operating income		2,967	3,621	9,625	17,185
Total assets		594,993		594,993		$ 766,596
Operating Segments | Health Care Services
Segment Reporting Information [Line Items]
Revenue		0	0	0	177,269
Segment operating income		$ 0	$ 0	$ 0	$ 5,816