Acquisitions, Dispositions and Other Significant Leasing Transactions - Revenue of Disposal Groups (Details) - Communities Disposed of Through Sale and Lease Terminations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Resident fees	$ 6,578	$ 28,173	$ 70,788
Facility operating expense	6,408	27,913	67,601
Assisted Living and Memory Care
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Resident fees	6,653	21,702	41,585
Facility operating expense	6,132	20,233	37,291
CCRCs
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Resident fees	(75)	6,471	29,203
Facility operating expense	$ 276	$ 7,680	$ 30,310