Business and Property Management Agreements with RMR LLC (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) employee agreement	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) employee agreement	Jun. 30, 2019 USD ($)
Real Estate Properties [Line Items]
Number of employees | employee	0		0
Amended and restate business management agreement | RMR LLC
Real Estate Properties [Line Items]
Number of management service agreements | agreement	2		2
Business management fees incurred	$ 8,411	$ 9,661	$ 18,971	$ 19,388
Incentive fee calculation period			3 years
Related party property management and construction management fee	921	27	$ 1,941	38
Related party reimbursement expenses	$ 139	$ 142	$ 266	$ 342