Segment Information (Details) $ in Thousands		12 Months Ended
	Jul. 01, 2021	Dec. 31, 2022 USD ($) segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jan. 01, 2021 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment		3
Revenue		$ 2,825,379	$ 2,758,259	$ 3,540,195
Segment operating income		594,413	500,951	797,147
General and administrative expense (including non-cash stock-based compensation expense)		168,594	184,916	206,575
Facility operating lease expense		165,294	174,358	224,033
Depreciation and amortization		347,444	337,613	359,226
Asset impairment		29,618	23,003	107,308
Loss (gain) on sale of communities, net		(73,850)	0	0
Loss (gain) on facility operating lease termination, net		0	(2,003)	(2,303)
Income (loss) from operations		(42,687)	(216,936)	(97,692)
Total interest expense		204,717	195,140	208,779
Total capital expenditures for property, plant and equipment, and leasehold intangibles		200,009	182,718	181,105
Assets		5,937,062	6,410,467
Equity in earnings (loss) of unconsolidated ventures		(10,782)	10,394	(2,107)
Goodwill		27,321	27,321		$ 154,100
CARES Act
Segment Reporting Information [Line Items]
Cash made available for Provider Relief Fund		80,469	12,368	115,749
Independent Living
Segment Reporting Information [Line Items]
Goodwill		$ 27,300	27,300	27,300
Health Care Services
Segment Reporting Information [Line Items]
Goodwill					$ 126,800
Health Care Services | Securities Purchase Agreement | HCA Healthcare, Inc.
Segment Reporting Information [Line Items]
Percentage of ownership sold in transaction	80.00%
Percentage of ownership after transaction	20.00%	20.00%
Operating segments | Independent Living
Segment Reporting Information [Line Items]
Revenue		$ 518,699	477,050	524,421
Segment operating income		158,950	146,108	182,813
Facility operating lease expense		39,700	42,162	60,445
Depreciation and amortization		79,521	74,922	70,803
Asset impairment		10,893	3,483	31,317
Total interest expense		48,788	45,209	44,682
Total capital expenditures for property, plant and equipment, and leasehold intangibles		44,857	36,992	47,889
Assets		1,267,825	1,349,341
Operating segments | Independent Living | CARES Act
Segment Reporting Information [Line Items]
Cash made available for Provider Relief Fund		10,906	1,512	11,823
Operating segments | Assisted Living and Memory Care
Segment Reporting Information [Line Items]
Revenue		1,815,722	1,595,684	1,753,861
Segment operating income		379,958	294,320	428,601
Facility operating lease expense		106,961	111,117	137,900
Depreciation and amortization		207,344	200,677	224,790
Asset impairment		11,613	14,384	61,640
Total interest expense		133,139	121,785	134,015
Total capital expenditures for property, plant and equipment, and leasehold intangibles		111,978	105,177	90,354
Assets		3,329,516	3,601,144
Operating segments | Assisted Living and Memory Care | CARES Act
Segment Reporting Information [Line Items]
Cash made available for Provider Relief Fund		60,630	5,963	62,585
Operating segments | CCRCs
Segment Reporting Information [Line Items]
Revenue		331,577	306,213	340,337
Segment operating income		43,485	34,109	53,180
Facility operating lease expense		13,883	15,932	20,406
Depreciation and amortization		38,039	37,891	38,426
Asset impairment		5,970	4,790	12,413
Total interest expense		21,251	18,756	19,928
Total capital expenditures for property, plant and equipment, and leasehold intangibles		20,467	19,086	18,709
Assets		664,502	693,386
Operating segments | CCRCs | CARES Act
Segment Reporting Information [Line Items]
Cash made available for Provider Relief Fund		8,933	1,788	18,454
Operating segments | Corporate and All Other
Segment Reporting Information [Line Items]
Revenue		159,381	202,043	531,879
Segment operating income		12,020	20,598	130,690
Facility operating lease expense		4,750	5,147	5,282
Depreciation and amortization		22,540	23,783	24,458
Asset impairment		1,142	346	1,938
Total interest expense		1,539	9,390	10,154
Total capital expenditures for property, plant and equipment, and leasehold intangibles		22,707	21,463	23,638
Assets		675,219	766,596
Equity in earnings (loss) of unconsolidated ventures		4,200	17,200	67,200
Operating segments | Health Care Services
Segment Reporting Information [Line Items]
Revenue		0	177,269	389,697
Segment operating income		0	5,816	1,863
Depreciation and amortization		0	340	749
Total capital expenditures for property, plant and equipment, and leasehold intangibles		0	0	515
Operating segments | Health Care Services | CARES Act
Segment Reporting Information [Line Items]
Cash made available for Provider Relief Fund		$ 0	$ 3,105	$ 22,887