Segment Information (Details) $ in Thousands		3 Months Ended
	Jul. 01, 2021	Mar. 31, 2022 USD ($) segment	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment		3
Revenue		$ 677,820	$ 749,445
Segment operating income		127,915	127,339
General and administrative expense (including non-cash stock-based compensation expense)		45,126	49,943
Facility lease expense		41,564	44,418
Depreciation and amortization		85,684	83,891
Asset impairment		9,075	10,677
Income (loss) from operations		(53,534)	(61,590)
Total assets		6,294,977		$ 6,410,467
Goodwill		27,321		27,321
Other operating income
Segment Reporting Information [Line Items]
Revenue		376	10,735
Independent Living
Segment Reporting Information [Line Items]
Goodwill		27,300		27,300
Independent Living | Other operating income
Segment Reporting Information [Line Items]
Revenue		2	1,364
Assisted Living and Memory Care | Other operating income
Segment Reporting Information [Line Items]
Revenue		356	5,104
CCRCs | Other operating income
Segment Reporting Information [Line Items]
Revenue		18	1,684
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	2,583
Operating Segments | Independent Living
Segment Reporting Information [Line Items]
Revenue		124,406	120,146
Segment operating income		37,684	37,329
Total assets		1,324,425		1,349,341
Operating Segments | Assisted Living and Memory Care
Segment Reporting Information [Line Items]
Revenue		432,488	392,042
Segment operating income		76,863	71,433
Total assets		3,573,911		3,601,144
Operating Segments | CCRCs
Segment Reporting Information [Line Items]
Revenue		80,456	73,463
Segment operating income		10,039	7,608
Total assets		686,480		693,386
Operating Segments | Corporate and All Other
Segment Reporting Information [Line Items]
Revenue		40,470	74,360
Segment operating income		3,329	8,566
Total assets		710,161		$ 766,596
Operating Segments | Health Care Services
Segment Reporting Information [Line Items]
Revenue		0	89,434
Segment operating income		$ 0	$ 2,403