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Senior Living Community Management Agreements - Narrative (Details) $ in Thousands			1 Months Ended	12 Months Ended
	Oct. 31, 2022 USD ($)	Jun. 09, 2021	Mar. 31, 2024 community	Dec. 31, 2024 USD ($) community property unit option	Dec. 31, 2023 USD ($) community	Dec. 31, 2022 USD ($) community	Dec. 31, 2021 unit community
Concentration Risk
Number of properties owned (property) \| property				367
Property operating expenses				$ 1,236,542	$ 1,174,151	$ 1,109,070
Disposal Group, Held-for-sale, Not Discontinued Operations
Concentration Risk
Number of properties owned (property) \| property				32
Affiliated Entity \| Five Star Management
Concentration Risk
Termination fees paid	$ 350
Senior Living Communities
Concentration Risk
Number of units in real estate property \| unit				27,000
Five Star \| Affiliated Entity
Concentration Risk
Management fees as a percentage of gross revenues				5.00%
Percentage of annual incentive fee				15.00%
Consumer price index annual estimated increase				2.00%
Trigger basis for capital investment ratio (percent)				6.00%
Business and property management agreement, number of agreements \| option				2
Renewal term (years)				5 years
Property management agreement expense				$ 42,474	40,119	37,037
Related party transaction capitalized amount				2,262	2,683	3,300
Five Star \| Affiliated Entity \| Operating Expense
Concentration Risk
Property management agreement expense				40,212	37,436	33,737
Five Star \| Affiliated Entity \| Rehabilitation Services
Concentration Risk
Property operating expenses				$ 0	$ 1,213	$ 6,289
Five Star \| Senior Living Communities \| Affiliated Entity
Concentration Risk
Number of communities managed \| community				118	119	119
Related party transactions, termination percentage		10.00%
Percentage of EBITDA threshold for contract termination		80.00%
Five Star \| Senior Living Communities \| Affiliated Entity \| Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations
Concentration Risk
Number of properties transitioned \| community							107
Number of units in real estate property \| unit							7,340
Amounts of transaction						$ 2,096
Five Star \| Senior Living Communities \| Affiliated Entity \| Disposal Group, Held-for-sale, Not Discontinued Operations
Concentration Risk
Number of properties owned (property) \| community							108
Third Party Managers \| Senior Living Communities \| Affiliated Entity
Concentration Risk
Number of communities managed \| community				114	113	111
Property management agreement expense				$ 23,283	$ 21,863	$ 20,739
Management agreement, term				5 years
Management agreement, extension term				2 years
Termination and other fees				$ 2,228
Incentive fee				$ 241
Third Party Managers \| Senior Living Communities \| Affiliated Entity \| Wisconsin And Illinois
Concentration Risk
Number of communities managed \| community			13
Third Party Managers \| Senior Living Communities \| Affiliated Entity \| Minimum
Concentration Risk
Management fees as a percentage of gross revenues				5.00%
Percentage of annual incentive fee				15.00%
Construction supervision fee				3.00%
Property management agreement, management fees				70.00%
Third Party Managers \| Senior Living Communities \| Affiliated Entity \| Maximum
Concentration Risk
Management fees as a percentage of gross revenues				6.00%
Percentage of annual incentive fee				25.00%
Construction supervision fee				5.00%
Property management agreement, management fees				80.00%