Business and Property Management Agreements with RMR (Details) $ in Thousands		12 Months Ended
	Jun. 22, 2021	Dec. 31, 2022 USD ($) employee agreement	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Real Estate Properties [Line Items]
Entity number of employees | employee		0
RMR
Real Estate Properties [Line Items]
Property management fees percentage of gross collected rents		3.00%
Construction supervision fees as percentage of construction costs		5.00%
RMR | Up C Transaction
Real Estate Properties [Line Items]
Recognized amortization of liability				$ 3,584
RMR | Property Management Fees
Real Estate Properties [Line Items]
Related party rate	3.00%
Operating expense from related party transaction		$ 3,998	$ 3,674	3,283
RMR | Construction And Supervision Fees Capitalized
Real Estate Properties [Line Items]
Amounts capitalized		2,131	815	292
RMR | RMR Inc.
Real Estate Properties [Line Items]
Recognized amortization of liability		$ 3,585	3,584
Amended and restated business management agreement | RMR
Real Estate Properties [Line Items]
Number of management agreements | agreement		2
Base management fee payable as a percentage of average historical cost of the real estate investments, excluding transferred assets for investments up to a specific amount		0.70%
Base management fee payable as percentage of aggregate book value of real estate assets or transferred assets		$ 250,000
Base management fee payable as percentage of average historical cost of real estate investments excluding transferred assets for investments exceeding specified amount		0.50%
Base management fee payable as percentage of average closing stock price on stock exchange		0.70%
Base management fee payable as percentage of average market capitalization exceeding specified amount		0.50%
Incentive fee as percentage of product of weighted average common shares outstanding		12.00%
Measurement period		3 years
Incentive fee, consecutive trading days for share price multiplier		10 days
Incentive fee, final trading days of relevant measurement period		30 days
Percentage of shares issued in payment of incentive management fees		1.50%
Business management fees		$ 35,495	42,137	36,830
Aggregate property management and construction supervision fees		6,128	4,489	3,575
Related party reimbursement expense		$ 3,258	$ 2,971	$ 2,618
Amended and restated business management agreement | RMR | Minimum
Real Estate Properties [Line Items]
Incentive management fee reduction		0.0200
Amended and restated business management agreement | RMR | Maximum
Real Estate Properties [Line Items]
Base management fee payable, average market capitalization		$ 250,000
Base management fee payable, threshold amount of other real estate investments		$ 250,000
Incentive management fee reduction		0.0500
Amended and restated business management agreement | Reit Management And Research
Real Estate Properties [Line Items]
Incentive fee, consecutive trading days for share price multiplier		10 days
Incentive fee, final trading days of relevant measurement period		30 days
Amended and restated business management agreement | Reit Management And Research | Up C Transaction
Real Estate Properties [Line Items]
Window for providing notice of termination of property management agreement for performance by the related party		60 days
Window providing notice of termination of property management agreement after change of control by related party		12 months
Termination fee remaining term assumption		10 years
Period over which transition services will be provided by the related party after termination of the agreement		120 days
Amended and restated business management agreement | Reit Management And Research | Minimum | Up C Transaction
Real Estate Properties [Line Items]
Termination fee term		19 years
Amended and restated business management agreement | Reit Management And Research | Maximum | Up C Transaction
Real Estate Properties [Line Items]
Termination fee term		20 years