Represents the number of directors.

No definition available.

Name:	rmr_NumberOfDirectors
Namespace Prefix:	rmr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Eligible number of votes for each share held.

+ References

No definition available.

+ Details

Name:	rmr_NumberOfVotesForEachShareHeld
Namespace Prefix:	rmr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

+ Details

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Face amount or stated value per share of common stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 30
-Article 5

+ Details

Name:	us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

+ References

+ Details

Name:	us-gaap_CommonStockSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 30
-Article 5

+ Details

Name:	us-gaap_CommonStockSharesOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of cash distribution paid to unit-holder of limited liability company (LLC).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70434-108055

+ Details

Name:	us-gaap_DistributionMadeToLimitedLiabilityCompanyLLCMemberCashDistributionsPaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of paid and unpaid cash dividends declared and applicable to holders of share-based compensation, for example, but not limited to, non-vested shares, stock options, or restricted stock units.

+ References

No definition available.

+ Details

Name:	us-gaap_DividendsShareBasedCompensationCash
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Gross number of share options (or share units) granted during the period.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Stock Split
-URI http://asc.fasb.org/extlink&oid=6525746

+ Details

Name:	us-gaap_StockholdersEquityNoteStockSplitConversionRatio1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_CapitalUnitsByClassAxis=us-gaap_CapitalUnitClassAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_StockCompensationPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TitleOfIndividualAxis=us-gaap_DirectorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=rmr_CommonClassB2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=rmr_CommonClassAndB1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=rmr_AbpTrustMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=us-gaap_SubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConsolidationItemsAxis=us-gaap_ConsolidationEliminationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=rmr_AbpTrustAndManagedReitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Shareholders' Equity (Details) $ / shares in Units, $ in Thousands						3 Months Ended		6 Months Ended
	Apr. 13, 2016 USD ($) $ / shares	Mar. 09, 2016 director $ / shares shares	Dec. 15, 2015 USD ($) $ / shares shares	Dec. 10, 2015 USD ($)	Nov. 25, 2015 USD ($) $ / shares	Mar. 31, 2016 $ / shares shares	Dec. 31, 2015 USD ($)	Mar. 31, 2016 USD ($) item $ / shares shares	Dec. 14, 2015 $ / shares	Sep. 30, 2015 $ / shares shares
Distribution made to Limited Liability Company (LLC) member \| $								$ 18,584
Class A membership units
Conversion ratio								1
Class A common shares
Common stock shares authorized						31,600,000		31,600,000		31,000,000
Common stock, par value (in dollars per share) \| $ / shares						$ 0.001		$ 0.001		$ 0.001
Number of votes per each share held \| item								1
Dividend declared (in dollars per share) \| $ / shares	$ 0.2993				$ 0.5260	$ 0.25
Dividend declared, Cash \| $	$ 4,791
Common stock shares outstanding						15,007,500		15,007,500		15,000,000
Class A common shares \| Equity Compensation Plan \| Independent Directors
Shares granted		2,500
Share value \| $ / shares		$ 23.27
Number of independent directors \| director		3
Class B-1 common shares
Common stock shares authorized						1,000,000		1,000,000		1,000,000
Common stock, par value (in dollars per share) \| $ / shares						$ 0.001		$ 0.001		$ 0.001
Number of votes per each share held \| item								10
Conversion ratio								1
Dividend declared (in dollars per share) \| $ / shares	$ 0.2993				$ 0.5260
Dividend declared, Cash \| $	$ 4,791
Common stock shares outstanding						1,000,000		1,000,000		1,000,000
Class B-2 common shares
Common stock shares authorized						15,000,000		15,000,000		15,000,000
Common stock, par value (in dollars per share) \| $ / shares						$ 0.001		$ 0.001		$ 0.001
Number of votes per each share held \| item								10
Common stock shares outstanding						15,000,000		15,000,000		15,000,000
Class A and Class B-1 Common Share
Dividend declared (in dollars per share) \| $ / shares									$ 0.25
Dividend declared, Cash \| $			$ 8,416		$ 8,416
Common stock shares outstanding			16,000,000
ABP Trust \| Class A common shares
Dividend declared, Cash \| $			$ 7,890
Common stock shares outstanding			15,000,000
RMR LLC
Dividend declared (in dollars per share) \| $ / shares			$ 0.5260
Dividend declared, Cash \| $			$ 16,306
RMR LLC \| Consolidation, Eliminations
Distribution made to Limited Liability Company (LLC) member \| $				$ 19,811
RMR LLC \| Class A common shares \| Equity Compensation Plan \| Independent Directors
Shares granted		7,500
RMR LLC \| ABP Trust
Distribution made to Limited Liability Company (LLC) member \| $							$ 18,584
RMR LLC \| ABP Trust and Managed REIT's
Distribution made to Limited Liability Company (LLC) member \| $				$ 38,395