Fair Value Measurements - Narrative (Details) $ in Thousands		3 Months Ended	12 Months Ended
	Jul. 01, 2021 USD ($)	Dec. 31, 2023 USD ($) community lease	Dec. 31, 2023 USD ($) community lease	Dec. 31, 2022 USD ($) community	Dec. 31, 2021 USD ($) community
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		$ 29,755	$ 29,755	$ 48,680
Total long-term debt		3,697,313	3,697,313	3,850,142
Long-term debt, fair value		$ 3,400,000	$ 3,400,000	3,400,000
Number of communities leased | lease		263	263
investment in unconsolidated ventures		$ 1,906	$ 1,906	55,333
HCA Healthcare, Inc. | Health Care Services
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value		27,400	27,400
investment in unconsolidated ventures	$ 100,000
Percentage of ownership after transaction	20.00%
Purchase price	$ 400,000
Non-cash impairment charge		$ 26,000
Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Operating lease right-of-use assets			8,300	13,700	$ 16,600
Property, plant and equipment and leasehold intangibles, net			$ 6,300	$ 15,900	$ 6,400
Condensed Consolidated Balance Sheet
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of communities leased | community		12	12	8	11
Estimated fair value		$ 16,400	$ 16,400	$ 30,900	$ 31,000
Reported Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long-term debt		3,700,000	3,700,000	3,900,000
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		$ 29,800	$ 29,800	$ 48,700