Segment Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) segment	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			3
Revenue	$ 757,291	$ 757,458	$ 2,261,346	$ 2,124,794
Segment operating income	184,901	194,464	558,078	460,843
General and administrative expense (including non-cash stock-based compensation expense)	43,076	41,331	137,021	128,209
Facility lease expense	53,145	41,317	149,784	124,419
Depreciation and amortization	85,932	86,922	255,314	259,229
Asset impairment	9,086	5,688	9,606	17,362
Loss (gain) on sale of communities, net	0	0	(36,296)	0
Income (loss) from operations	(6,338)	19,206	42,649	(68,376)
Total assets	5,829,069		5,829,069		$ 5,937,062
Goodwill	27,321		27,321		27,321
Independent Living
Segment Reporting Information [Line Items]
Goodwill	27,300		27,300		27,300
Operating Segments | Independent Living
Segment Reporting Information [Line Items]
Revenue	141,449	137,626	422,993	388,769
Segment operating income	44,702	46,395	137,896	122,788
Total assets	1,223,941		1,223,941		1,267,825
Operating Segments | Assisted Living and Memory Care
Segment Reporting Information [Line Items]
Revenue	496,232	491,818	1,475,322	1,365,172
Segment operating income	126,731	130,039	375,940	294,490
Total assets	3,366,695		3,366,695		3,329,516
Operating Segments | CCRCs
Segment Reporting Information [Line Items]
Revenue	82,065	87,563	251,446	249,215
Segment operating income	10,902	15,063	36,589	33,940
Total assets	631,255		631,255		664,502
Operating Segments | Corporate and All Other
Segment Reporting Information [Line Items]
Revenue	37,545	40,451	111,585	121,638
Segment operating income	2,566	$ 2,967	7,653	$ 9,625
Total assets	$ 607,178		$ 607,178		$ 675,219