Related Person Transactions - Directors' and Officers' Liability Insurance (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
RMR LLC
Related Party Transaction [Line Items]
Premium paid for combined directors' and officers' liability insurance policy	$ 201	$ 247	$ 253

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Balance Type:	na
Period Type:	duration