Business and Property Management Agreements with RMR LLC (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($) employee	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) property employee management_agreement	Jun. 30, 2016 USD ($)
Related person transactions
Number of employees | employee	0		0
Property management and construction supervision fees	$ 2,708	$ 2,686	$ 4,888	$ 5,232
Property management and construction supervision fees paid	2,383	2,171	4,763	4,299
Professional fees	67	67	134	134
RMR LLC
Related person transactions
Related party transaction business management fees related to subsidiary level management	20,431		33,212
Business management fees incurred		$ 9,243		$ 17,590
Related party transaction amortization of liability	725		787
Related party transaction business management agreement, incentive fee paid	$ 10,760		$ 14,026
Related party transaction, incentive fee payable assessment period			3 years
Senior Living Communities | RMR Inc
Related person transactions
Number of consecutive renewal terms of agreement | management_agreement			2
Number of communities managed by related party | property			1