Amount of income (loss) for proportionate share of equity method investee's income (loss).

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Name:	us-gaap_IncomeLossFromEquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Related Person Transactions (Details) $ in Thousands	3 Months Ended
Related Person Transactions (Details) $ in Thousands	Mar. 31, 2020 USD ($) agreement shares	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Related person transactions
Equity in earnings of an investee	$ 0	$ 404
Five Star
Related person transactions
Equity securities investment (in shares) \| shares	10,691,658
Investment owned, percentage of total shares outstanding	33.90%
RMR LLC
Related person transactions
Number of management agreements \| agreement	2
AIC
Related person transactions
Equity method investments	$ 298		$ 298
Equity in earnings of an investee	$ 404
RMR LLC \| Five Star
Related person transactions
Investment owned, percentage of total shares outstanding	6.30%