Segment Information (Details)	12 Months Ended
	Dec. 31, 2024 USD ($) segment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	3
Revenue and other operating income	$ 3,125,487,000	$ 3,015,829,000	$ 2,825,379,000
Total facility operating expenses	2,183,261,000	2,129,800,000	2,083,605,000
Segment operating income	799,310,000	746,704,000	594,413,000
General and administrative expense (including non-cash stock-based compensation expense)	185,850,000	178,894,000	168,594,000
Facility operating lease expense	200,587,000	202,410,000	165,294,000
Depreciation and amortization	357,788,000	342,712,000	347,444,000
Asset impairment	8,557,000	40,572,000	29,618,000
Loss (gain) on sale of communities, net	0	(36,296,000)	(73,850,000)
Income (loss) from operations	46,528,000	18,412,000	(42,687,000)
Total interest expense	252,575,000	238,274,000	204,717,000
Total capital expenditures for property, plant and equipment, and leasehold intangibles	204,350,000	228,592,000	200,009,000
Assets	6,335,562,000	5,573,435,000
Equity in earnings (loss) of unconsolidated ventures	0	(3,996,000)	(10,782,000)
Goodwill	27,321,000	27,321,000
CARES Act
Segment Reporting Information [Line Items]
Cash made available for Provider Relief Fund	0	9,073,000	80,469,000
Independent Living
Segment Reporting Information [Line Items]
Goodwill	27,300,000	$ 27,300,000	27,300,000
CCRCs | Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations | Communities Disposed of Through Sale
Segment Reporting Information [Line Items]
Number of communities disposed of		2
Cash proceeds		$ 25,600,000
Mortgage debt repaid		29,600,000
Gain on sale of communities		36,300,000
Operating segments | Independent Living
Segment Reporting Information [Line Items]
Revenue and other operating income	598,922,000	564,499,000	518,699,000
Community labor expenses	230,037,000	221,112,000	213,965,000
Other facility operating expenses	173,803,000	158,742,000	145,784,000
Segment operating income	195,082,000	184,645,000	158,950,000
Facility operating lease expense	37,824,000	39,114,000	39,700,000
Depreciation and amortization	92,785,000	83,637,000	79,521,000
Asset impairment	2,285,000	1,647,000	10,893,000
Total interest expense	65,342,000	61,624,000	48,788,000
Total capital expenditures for property, plant and equipment, and leasehold intangibles	48,658,000	51,188,000	44,857,000
Assets	1,252,736,000	1,206,021,000
Operating segments | Independent Living | CARES Act
Segment Reporting Information [Line Items]
Cash made available for Provider Relief Fund	0	487,000	10,906,000
Operating segments | Assisted Living and Memory Care
Segment Reporting Information [Line Items]
Revenue and other operating income	2,038,660,000	1,968,440,000	1,815,722,000
Community labor expenses	994,687,000	979,926,000	977,780,000
Other facility operating expenses	510,670,000	486,197,000	457,984,000
Segment operating income	533,303,000	502,317,000	379,958,000
Facility operating lease expense	147,899,000	146,166,000	106,961,000
Depreciation and amortization	202,996,000	196,994,000	207,344,000
Asset impairment	5,927,000	11,574,000	11,613,000
Total interest expense	150,610,000	141,330,000	133,139,000
Total capital expenditures for property, plant and equipment, and leasehold intangibles	122,384,000	121,240,000	111,978,000
Assets	3,983,311,000	3,315,921,000
Operating segments | Assisted Living and Memory Care | CARES Act
Segment Reporting Information [Line Items]
Cash made available for Provider Relief Fund	0	8,008,000	60,630,000
Operating segments | CCRCs
Segment Reporting Information [Line Items]
Revenue and other operating income	334,468,000	333,404,000	331,577,000
Community labor expenses	183,322,000	192,860,000	196,279,000
Other facility operating expenses	90,742,000	90,963,000	91,813,000
Segment operating income	60,404,000	49,581,000	43,485,000
Facility operating lease expense	13,052,000	12,943,000	13,883,000
Depreciation and amortization	34,882,000	36,951,000	38,039,000
Asset impairment	345,000	1,368,000	5,970,000
Total interest expense	23,595,000	24,889,000	21,251,000
Total capital expenditures for property, plant and equipment, and leasehold intangibles	18,214,000	37,414,000	20,467,000
Assets	640,720,000	612,521,000
Operating segments | CCRCs | CARES Act
Segment Reporting Information [Line Items]
Cash made available for Provider Relief Fund	0	578,000	8,933,000
Operating segments | All Other
Segment Reporting Information [Line Items]
Revenue and other operating income	153,437,000	149,486,000	159,381,000
Segment operating income	10,521,000	10,161,000	12,020,000
Facility operating lease expense	1,812,000	4,187,000	4,750,000
Depreciation and amortization	27,125,000	25,130,000	22,540,000
Asset impairment	0	25,983,000	1,142,000
Total interest expense	13,028,000	10,431,000	1,539,000
Total capital expenditures for property, plant and equipment, and leasehold intangibles	15,094,000	18,750,000	22,707,000
Assets	$ 458,795,000	438,972,000
Equity in earnings (loss) of unconsolidated ventures		$ 900,000	4,200,000
Operating segments | Health Care Services
Segment Reporting Information [Line Items]
Segment operating income			$ 135,000,000