Represents the quarterly dividend payable for each share of common stock outstanding.

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The initial other liabilities recorded which is the difference of the total consideration paid and the fair market value of the investment.

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Aggregate dividends declared during the period for each share of common stock outstanding.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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The change in other comprehensive income during the reporting period, net of tax, for an item that is not separately disclosed.

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Cumulative number of shares issued or sold by the subsidiary or equity method investee on all stock transactions.

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Related Person Transactions - REITs, for which RMR LLC provides Management Services (Details) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended
	Apr. 13, 2016 $ / shares	Jun. 30, 2015 agreement	Mar. 31, 2016 USD ($) agreement shares	Mar. 31, 2015 USD ($) shares	Apr. 25, 2016 $ / shares	Dec. 31, 2015 USD ($) $ / shares
Related Person Transaction
Proceeds from Equity Method Investment, Dividends or Distributions			$ 9,117	$ 2,176
Investment at carrying value			493,259			$ 491,369
Recognized income (loss) related to investment			$ 9,934	(316)
SIR
Related Person Transaction
Percentage of ownership interest			27.90%
Quarterly dividend payable on common stock (in dollars per share) \| $ / shares					$ 0.50
Proceeds from Equity Method Investment, Dividends or Distributions			$ 12,459	13,530
SIR
Related Person Transaction
Percentage of ownership interest			27.90%
Proceeds from Equity Method Investment, Dividends or Distributions			$ 12,459	13,530
Investment at carrying value			493,259
Recognized income (loss) related to investment			9,857	$ 2,176
SIR \| SIR
Related Person Transaction
Number of common shares sold in public offering \| shares				28,453,447
Recognized income (loss) related to investment			$ 77	$ 72
RMR LLC
Related Person Transaction
Percentage of ownership interest			27.90%
AIC
Related Person Transaction
Investment at carrying value			$ 7,075
Recognized income (loss) related to investment			77	72
Other Comprehensive Income, Other, Net of Tax			$ 52	$ 45
AIC \| RMR LLC
Related Person Transaction
Number of entities to whom RMR provides management services \| agreement			6
RMR Inc \| RMR LLC
Related Person Transaction
Number of entities to whom RMR provides management services \| agreement		3
Management agreement continuing terms (in years)		20 years
Class A common shares \| RMR LLC
Related Person Transaction
Shares holding \| shares			1,214,225
Common distributions declared (in dollars per share) \| $ / shares	$ 0.2993
Quarterly dividend payable on common stock (in dollars per share) \| $ / shares	$ 0.25					$ 0.0493
RMR Inc
Related Person Transaction
Initial Other Liabilities			$ 21,482
Recognized amortization of the liability			$ 272