Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended								12 Months Ended
	Dec. 14, 2015	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues		$ 479,278	$ 543,516	$ 550,299	$ 474,118	$ 467,440	$ 511,886	$ 507,066	$ 435,512	$ 2,047,211	$ 1,921,904	$ 1,736,322
Net income		63,186	51,812	56,061	52,051	(19,494)	61,185	83,146	41,581	223,110	166,418	197,185
Net income available for common shareholders		$ 58,020	$ 46,646	$ 50,895	$ 46,885	$ (24,660)	$ 56,019	$ 77,980	$ 36,415	$ 202,446	$ 145,754	$ 176,521
Net income available for common shareholders per common share: Basic and diluted (in dollars per share)		$ 0.35	$ 0.30	$ 0.34	$ 0.31	$ (0.16)	$ 0.37	$ 0.52	$ 0.24	$ 1.30	$ 0.97	$ 1.18
Distributions per common share (in dollars per share)		$ 0.51	$ 0.51	$ 0.51	$ 0.50	0.70	$ 0.50	$ 0.50	$ 0.49
RMR Inc
Non cash distributions per common share	$ 0.1974					$ 0.1974