Related Person Transactions (Details)	Sep. 30, 2021 hotel travelCenter agreement travel_center shares
Travel centers
Related Party Transaction [Line Items]
Number of properties owned \| travelCenter	179
Hotel
Related Party Transaction [Line Items]
Number of properties owned \| hotel	304
Sonesta Int'l Hotels Corp
Related Party Transaction [Line Items]
Noncontrolling interest, ownership percentage	34.00%
RMR LLC \| Travel Centers of America
Related Party Transaction [Line Items]
Shares included in investment securities (in shares) \| shares	658,506
Noncontrolling interest, ownership percentage	4.50%
Travel Centers of America
Related Party Transaction [Line Items]
Shares included in investment securities (in shares) \| shares	1,184,797
Percentage of total shares outstanding	8.10%
Travel Centers of America \| Travel centers
Related Party Transaction [Line Items]
Number of properties owned \| travel_center	179
RMR LLC
Related Party Transaction [Line Items]
Number of management service agreements \| agreement	2
Sonesta Int'l Hotels Corp \| Hotel
Related Party Transaction [Line Items]
Number of properties owned \| hotel	261

Represents the number of shares held as a percentage of the total shares outstanding at the end of the period.

No definition available.

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- Definition

Represents the service agreements entered into by the entity for availing services from other entities.

+ References

No definition available.

+ Details

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- Definition

Balance held at close of period in number of shares.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section 50
-Paragraph 6
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=99383244&loc=d3e12121-115841

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-12B(Column B))
-URI http://asc.fasb.org/extlink&oid=122147990&loc=d3e611197-123010

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- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

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- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

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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.

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