Represents the number of agreements with RMR LLC to provide management services to the company.

No definition available.

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- Definition

Represents the number of entities to whom related party provides management services.

+ References

No definition available.

+ Details

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- Definition

This element represents the aggregate cost of investments accounted for under the equity method of accounting.

+ 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 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07.1(c))
-URI http://asc.fasb.org/extlink&oid=6488393&loc=d3e606610-122999

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
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- Details

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- Details

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- Details

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Data Type:	na
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- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

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Related Person Transactions - REITs, for which RMR LLC provides Management Services (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) agreement company shares	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
SIR
Related Party Transaction [Line Items]
Shares holding (in shares) \| shares	24,918,421
Percentage of outstanding shares owned	27.80%
RMR Inc \| Class A common shares
Related Party Transaction [Line Items]
Shares holding (in shares) \| shares	1,214,225
RMR LLC
Related Party Transaction [Line Items]
Number of agreements \| agreement	2
Revenue from related party \| $	$ 218	$ 92
AIC
Related Party Transaction [Line Items]
Number of entities to whom services are provided \| company	4
Carrying value of equity method investments \| $	$ 8,255		$ 8,304