Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) property joint_venture segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 05, 2015 USD ($) shares
Schedule of Equity Method Investments [Line Items]
Number of joint ventures | joint_venture	2
Number of properties (in properties) | property	160
Unamortized discount (premium), net	$ 14,145
Number of business segments | segment	1
Joint Venture Property 1
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest	51.00%
Joint Venture Property 2
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest	50.00%
RMR Inc
Schedule of Equity Method Investments [Line Items]
Equity securities, FV-NI (in shares) | shares				1,541,201
Equity securities, FV-NI, cost				$ 17,462
Unconsolidated Joint Ventures
Schedule of Equity Method Investments [Line Items]
Number of joint ventures | joint_venture	2
Number of properties (in properties) | property	3
Unconsolidated Joint Ventures | Joint Venture Property 1
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest	51.00%
Unconsolidated Joint Ventures | Joint Venture Property 2
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest	50.00%
Unconsolidated Joint Ventures
Schedule of Equity Method Investments [Line Items]
Number of joint ventures | joint_venture	2
Number of properties (in properties) | property	3
Unconsolidated Joint Ventures | Mortgage Note Payable
Schedule of Equity Method Investments [Line Items]
Principal balance	$ 82,000	$ 82,000
RMR Inc
Schedule of Equity Method Investments [Line Items]
Equity securities, FV-NI				$ 39,833
Amortization of liability	1,087	$ 1,087	$ 1,087
Amortization of liability, year one	1,087
Amortization of liability, year two	1,087
Amortization of liability, year three	1,087
Amortization of liability, year four	1,087
Amortization of liability, year five	1,087
Amortization of liability, thereafter	$ 8,710