Organization	12 Months Ended
Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization The RMR Group Inc., or RMR Inc., a Maryland corporation, is a holding company, and substantially all of its business is conducted by its majority owned subsidiary The RMR Group LLC, or RMR LLC, historically a Delaware limited liability company and, as of June 5, 2015, a Maryland limited liability company. In these financial statements, unless otherwise indicated, “we,” us” and “our” refer to RMR Inc. and its direct and indirect subsidiaries, including RMR LLC. RMR Inc. serves as the sole managing member of RMR LLC and, in that capacity, operates and controls the business and affairs of RMR LLC. RMR Inc. was incorporated in Maryland on May 28, 2015 in contemplation of the June 5, 2015 transaction described in Note 6, Related Person Transactions, or the Up-C Transaction. Prior to the Up-C Transaction, RMR Inc. had not engaged in any business or other activities, except in connection with its incorporation. The Up‑C Transaction and preceding reorganization transactions resulted in a change in the reporting entity for periods prior to June 5, 2015 due to the contribution to RMR LLC of operating entities under common control as described in Note 6, Related Person Transactions. These operating entities were then wholly owned by ABP Trust (formerly known as Reit Management & Research Trust), historically a Massachusetts business trust, and as of January 20, 2016, a Maryland statutory trust, or by Barry M. Portnoy and Adam D. Portnoy, our Founders, who are the beneficial owners of ABP Trust. ABP Trust and its beneficial owners are referred to herein collectively as the Members. The operating entities include RMR Advisors LLC, a Maryland limited liability company which was formerly a Massachusetts corporation named RMR Advisors, Inc., or RMR Advisors, and RMR Intl LLC, a Maryland limited liability company, or RMR Intl. These transactions among entities under common control have been accounted for using the pooling method of accounting as if the operations of RMR Advisors and RMR Intl were consolidated as of the beginning of the earliest period presented in our consolidated financial statements and the ownership structure as of June 5, 2015 had been in existence throughout the periods covered by our consolidated financial statements. The contribution of RMR Advisors and RMR Intl increased net income by $245 and $927, and increased other comprehensive income (loss) by $440 and ($125) in the period October 1, 2014 to June 4, 2015 and the fiscal year ended September 30, 2014, respectively. As of September 30, 2016, RMR Inc. owns 15,082,432 class A membership units of RMR LLC, or Class A Units, and 1,000,000 class B membership units of RMR LLC, or Class B Units. The aggregate RMR LLC membership units RMR Inc. owns represent 51.7% of the economic interest of RMR LLC. We refer to economic interest as the right of a holder of a Class A Unit or Class B Unit to share in distributions made by RMR LLC and, upon liquidation, dissolution or winding up of RMR LLC, to share in the assets of RMR LLC after payments to creditors. ABP Trust owns 15,000,000 redeemable Class A Units, representing 48.3% of the economic interest of RMR LLC, which is presented as a noncontrolling interest within the consolidated financial statements. RMR LLC was founded in 1986 to manage public investments in real estate and, as of September 30, 2016, managed a diverse portfolio of publicly owned real estate and real estate related businesses. RMR LLC manages: Government Properties Income Trust, or GOV, a publicly traded real estate investment trust, or REIT, that primarily owns properties that are majority leased to the U.S. government and state governments; Hospitality Properties Trust, or HPT, a publicly traded REIT that primarily owns hotel and travel center properties; Select Income REIT, or SIR, a publicly traded REIT that primarily owns properties that are net leased to single tenants; and Senior Housing Properties Trust, or SNH, a publicly traded REIT that primarily owns healthcare senior living and medical office buildings. Hereinafter, GOV, HPT, SIR and SNH are collectively referred to as the Managed REITs. RMR LLC also provides management services to other publicly traded and private businesses, including: Five Star Quality Care, Inc., or Five Star, a publicly traded operator of senior living communities, many of which are owned by SNH; Sonesta International Hotels Corporation, or Sonesta, a privately owned franchisor and operator of hotels, resorts and cruise ships in the United States, Latin America, the Caribbean and the Middle East, some of whose U.S. hotels are owned by HPT; and TravelCenters of America LLC, or TA, an operator of travel centers along the U.S. Interstate Highway System, many of which are owned by HPT, convenience stores with retail gas stations and restaurants. Hereinafter, Five Star, Sonesta and TA are collectively referred to as the Managed Operators. In addition, RMR LLC also provides management services to certain related private companies, including Affiliates Insurance Company, or AIC, an Indiana insurance company, and ABP Trust and its subsidiaries. During the periods presented until September 30, 2014, RMR LLC provided business and property management services to Equity Commonwealth, or EQC, a publicly traded REIT that primarily owns office properties, and thereafter RMR LLC provided certain transition services to EQC through October 31, 2015. For periods prior to June 5, 2015, no historical member of RMR LLC was obligated personally for any debts, obligations or liabilities of RMR LLC solely by reason of being a member. RMR Advisors was founded in 2002. RMR Advisors is the advisor to RMR Real Estate Income Fund, or RIF. RIF is a closed end investment company focused on investing in real estate securities, including REITs and other dividend paying securities, but excluding our Client Companies, as defined below. On August 5, 2016, we acquired certain assets of Tremont Realty Capital LLC, or the Tremont business, which specializes in commercial real estate finance, principally capital for commercial real estate sponsors and serving as advisor to private funds and separately managed accounts that principally make commercial real estate debt investments. As part of this transaction, our wholly owned subsidiary, Tremont Realty Advisors LLC, or Tremont Advisors, an investment advisor registered with the SEC, was assigned the investment management contracts of investment advisory clients of the Tremont business. Tremont Advisors advises private funds and separately managed accounts that invest in commercial real estate debt, including secured mortgage debt and mezzanine financings. Tremont Advisors may also provide advice with respect to commercial real estate that may become owned by its clients. RMR Intl was founded in 2012 and is the owner of RMR Australia Asset Management Pty Ltd, or RMR Australia, a company founded in 2012 to manage properties owned by EQC located in Australia. RMR Australia holds an Australian financial services license granted by the Australian Securities & Investments Commission. In these financial statements, we refer to the Managed REITs, the Managed Operators, RIF, AIC, ABP Trust and the clients of the Tremont business as our Client Companies.

Organization

The RMR Group Inc., or RMR Inc., a Maryland corporation, is a holding company, and substantially all of its business is conducted by its majority owned subsidiary The RMR Group LLC, or RMR LLC, historically a Delaware limited liability company and, as of June 5, 2015, a Maryland limited liability company. In these financial statements, unless otherwise indicated, “we,” us” and “our” refer to RMR Inc. and its direct and indirect subsidiaries, including RMR LLC. RMR Inc. serves as the sole managing member of RMR LLC and, in that capacity, operates and controls the business and affairs of RMR LLC. RMR Inc. was incorporated in Maryland on May 28, 2015 in contemplation of the June 5, 2015 transaction described in Note 6, Related Person Transactions, or the Up-C Transaction. Prior to the Up-C Transaction, RMR Inc. had not engaged in any business or other activities, except in connection with its incorporation.

The Up‑C Transaction and preceding reorganization transactions resulted in a change in the reporting entity for periods prior to June 5, 2015 due to the contribution to RMR LLC of operating entities under common control as described in Note 6, Related Person Transactions. These operating entities were then wholly owned by ABP Trust (formerly known as Reit Management & Research Trust), historically a Massachusetts business trust, and as of January 20, 2016, a Maryland statutory trust, or by Barry M. Portnoy and Adam D. Portnoy, our Founders, who are the beneficial owners of ABP Trust. ABP Trust and its beneficial owners are referred to herein collectively as the Members. The operating entities include RMR Advisors LLC, a Maryland limited liability company which was formerly a Massachusetts corporation named RMR Advisors, Inc., or RMR Advisors, and RMR Intl LLC, a Maryland limited liability company, or RMR Intl. These transactions among entities under common control have been accounted for using the pooling method of accounting as if the operations of RMR Advisors and RMR Intl were consolidated as of the beginning of the earliest period presented in our consolidated financial statements and the ownership structure as of June 5, 2015 had been in existence throughout the periods covered by our consolidated financial statements. The contribution of RMR Advisors and RMR Intl increased net income by $245 and $927, and increased other comprehensive income (loss) by $440 and ($125) in the period October 1, 2014 to June 4, 2015 and the fiscal year ended September 30, 2014, respectively.

As of September 30, 2016, RMR Inc. owns 15,082,432 class A membership units of RMR LLC, or Class A Units, and 1,000,000 class B membership units of RMR LLC, or Class B Units. The aggregate RMR LLC membership units RMR Inc. owns represent 51.7% of the economic interest of RMR LLC. We refer to economic interest as the right of a holder of a Class A Unit or Class B Unit to share in distributions made by RMR LLC and, upon liquidation, dissolution or winding up of RMR LLC, to share in the assets of RMR LLC after payments to creditors. ABP Trust owns 15,000,000 redeemable Class A Units, representing 48.3% of the economic interest of RMR LLC, which is presented as a noncontrolling interest within the consolidated financial statements.

RMR LLC was founded in 1986 to manage public investments in real estate and, as of September 30, 2016, managed a diverse portfolio of publicly owned real estate and real estate related businesses. RMR LLC manages: Government Properties Income Trust, or GOV, a publicly traded real estate investment trust, or REIT, that primarily owns properties that are majority leased to the U.S. government and state governments; Hospitality Properties Trust, or HPT, a publicly traded REIT that primarily owns hotel and travel center properties; Select Income REIT, or SIR, a publicly traded REIT that primarily owns properties that are net leased to single tenants; and Senior Housing Properties Trust, or SNH, a publicly traded REIT that primarily owns healthcare senior living and medical office buildings. Hereinafter, GOV, HPT, SIR and SNH are collectively referred to as the Managed REITs. RMR LLC also provides management services to other publicly traded and private businesses, including: Five Star Quality Care, Inc., or Five Star, a publicly traded operator of senior living communities, many of which are owned by SNH; Sonesta International Hotels Corporation, or Sonesta, a privately owned franchisor and operator of hotels, resorts and cruise ships in the United States, Latin America, the Caribbean and the Middle East, some of whose U.S. hotels are owned by HPT; and TravelCenters of America LLC, or TA, an operator of travel centers along the U.S. Interstate Highway System, many of which are owned by HPT, convenience stores with retail gas stations and restaurants. Hereinafter, Five Star, Sonesta and TA are collectively referred to as the Managed Operators. In addition, RMR LLC also provides management services to certain related private companies, including Affiliates Insurance Company, or AIC, an Indiana insurance company, and ABP Trust and its subsidiaries. During the periods presented until September 30, 2014, RMR LLC provided business and property management services to Equity Commonwealth, or EQC, a publicly traded REIT that primarily owns office properties, and thereafter RMR LLC provided certain transition services to EQC through October 31, 2015. For periods prior to June 5, 2015, no historical member of RMR LLC was obligated personally for any debts, obligations or liabilities of RMR LLC solely by reason of being a member.

RMR Advisors was founded in 2002. RMR Advisors is the advisor to RMR Real Estate Income Fund, or RIF. RIF is a closed end investment company focused on investing in real estate securities, including REITs and other dividend paying securities, but excluding our Client Companies, as defined below.

On August 5, 2016, we acquired certain assets of Tremont Realty Capital LLC, or the Tremont business, which specializes in commercial real estate finance, principally capital for commercial real estate sponsors and serving as advisor to private funds and separately managed accounts that principally make commercial real estate debt investments. As part of this transaction, our wholly owned subsidiary, Tremont Realty Advisors LLC, or Tremont Advisors, an investment advisor registered with the SEC, was assigned the investment management contracts of investment advisory clients of the Tremont business. Tremont Advisors advises private funds and separately managed accounts that invest in commercial real estate debt, including secured mortgage debt and mezzanine financings. Tremont Advisors may also provide advice with respect to commercial real estate that may become owned by its clients.

RMR Intl was founded in 2012 and is the owner of RMR Australia Asset Management Pty Ltd, or RMR Australia, a company founded in 2012 to manage properties owned by EQC located in Australia. RMR Australia holds an Australian financial services license granted by the Australian Securities & Investments Commission.

In these financial statements, we refer to the Managed REITs, the Managed Operators, RIF, AIC, ABP Trust and the clients of the Tremont business as our Client Companies.