Related Person Transactions (Details) $ / shares in Units, $ in Thousands	Jul. 01, 2019 USD ($) $ / shares	Jun. 30, 2019 USD ($) agreement shares	Dec. 31, 2018 USD ($)
RMR Inc | Class A common shares
Related person transactions
Equity securities investment (in shares) | shares		2,637,408
Number of management agreements | agreement		2
Five Star
Related person transactions
Equity securities investment (in shares) | shares		4,235,000
Investment owned, percentage of total shares outstanding		8.30%
AIC
Related person transactions
Equity method investments | $		$ 9,303	$ 8,632
RMR LLC | Five Star
Related person transactions
Investment owned, percentage of total shares outstanding		35.40%
Subsequent Event | RMR Inc | Class A common shares
Related person transactions
Sale of stock, price per share (in dollars per share) | $ / shares	$ 40.00
Proceeds from sale of investments | $	$ 98,903