Related Person Transactions - REITs, for which RMR LLC provides Management Services (Details)						1 Months Ended		12 Months Ended
	Jan. 04, 2016	Jan. 01, 2016 USD ($) item property	Jul. 23, 2015 USD ($) state item room property	May. 09, 2015 USD ($) company item shares	Jun. 28, 2013	Jun. 30, 2015 USD ($)	Jan. 31, 2012 USD ($) property	Dec. 31, 2015 USD ($) item period property	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jun. 30, 2014 USD ($)	Dec. 31, 2013 USD ($)	Jun. 30, 2013 USD ($)	Oct. 31, 2015 USD ($)	Aug. 31, 2015 USD ($)	Apr. 28, 2015 USD ($)
Related Party Transaction [Line Items]
Purchase price excluding acquistion cost								$ 492,924,000						$ 15,000,000
Earnings (losses) recognized related to equity investments								21,000		$ 94,000		$ 334,000
Real Estate Aggregate Purchase Price								$ 492,924,000						$ 15,000,000
Hotels | Sonesta ES Suites
Related Party Transaction [Line Items]
Number of properties acquired | property			9
Number of hotel suites | room			1,095
Number of states hotels to be acquired located | state			8
Travel Centers of America LLC
Related Party Transaction [Line Items]
Number of properties acquired | property								14
Purchase price excluding acquistion cost								$ 279,383,000
Real Estate Aggregate Purchase Price								279,383,000
RMR LLC
Related Party Transaction [Line Items]
Aggregate coverage of combined directors' and officers' liability insurance policy purchased by the related party															$ 10,000,000
Aggregate additional coverage of combined directors' and officers' liability insurance policy purchased by the related party															20,000,000
Non-indemnifiable coverage of combined directors' and officers' liability insurance policy purchased by the related party															$ 5,000,000
Premium paid for combined directors' and officers' liability insurance policy								463,000		624,000		624,000
AIC
Related Party Transaction [Line Items]
Number of other remaining shareholders | item				6
Aggregate value of shares purchased under shareholder agreements				$ 825,000				6,034,000
Percentage of interest, equity method				14.30%
Service fee annual earned premium payable (as a percent)						3.00%
Coverage of property insurance						$ 500,000,000
Combined property insurance policy term						3 years
Terrorism property insurance term						1 year
Property insurance premium									$ 4,099,000		$ 11,851,000		$ 6,842,000
Equity method investments, carrying value								6,834,000		6,834,000		5,913,000
Earnings (losses) recognized related to equity investments								$ 20,000		94,000		334,000
Number of other companies owning outstanding shares | company				4
Number of shares purchased under shareholder agreement | shares				2,857
Sonesta Int'l Hotels Corp
Related Party Transaction [Line Items]
Amount of purchase price and leasehold interest							$ 150,500,000
Number of hotels managed | property							31
Fixed minimum return								8.00%
Percentage of base management fee					3.00%			3.00%
Percentage of reservation fee								1.50%
Percentage of system fee for centralized services								1.50%
Percentage of procurement and construction supervision fee								3.00%
Percentage of incentive fee								20.00%
Number of automatic renewal terms | period								2
Duration of management agreement period								15 years
Threshold period beyond which the agreement can be terminated without termination fee								3 years
Threshold percentage of return								6.00%
Threshold period over which minimum return to be achieved | item								3
Benchmark period for attaining minimum return								4 years
Average fee earned period, if agreement not terminated								3 years
Termination fee discount rate								8.00%
Percentage of base management fee for limited service hotels								5.00%
Management agreement fees and expenses								$ 21,482,000		17,800,000		10,902,000
Procurement and construction supervision fees								1,607,000		3,309,000		$ 2,976,000
Reimbursement of capital expenditures payable								$ 3,968,000		$ 5,250,000
Threshold percentage of reimbursement under guest loyalty program								1.00%
Threshold percentage of reimbursement under marketing program								1.00%
Threshold percentage of reimbursement under third-party reservation transmission expenses								$ 0.8
Annual rent payable as a percentage of net profit					75.00%
Purchase price excluding acquistion cost																$ 750,000
Real Estate Aggregate Purchase Price																$ 750,000
Sonesta Int'l Hotels Corp | Subsequent event
Related Party Transaction [Line Items]
Number of properties acquired | property		2
Number of hotel suites | item		262
Purchase price excluding acquistion cost		$ 12,000,000
Threshold stipulated measurement period for termination rights	18 months
Number of long term management agreement | item		2
Real Estate Aggregate Purchase Price		$ 12,000,000
Sonesta Int'l Hotels Corp | Sonesta ES Suites
Related Party Transaction [Line Items]
Number of properties acquired | property			9
Number of hotel suites | item			1,095
Number of states hotels to be acquired located | state			8
Purchase price excluding acquistion cost			$ 85,000,000
Real Estate Aggregate Purchase Price			85,000,000
Amount expected to be provided for renovation for acquisitions made			$ 45,000,000