Area Of Real Estate Property, Percentage Upon Completion Of Re-Development

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Lessor, Operating Lease, Lease Not yet Commenced, Annual Base Rent

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Lessor, Operating Lease, Lease Not yet Commenced, Annual Base Rent Increase Period

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Lessor, Operating Lease, Lease Not yet Commenced, Annual Percentage Increase

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Lessor, Operating Lease, Lease Not yet Commenced, Deferred Payment Plan Period

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Lessor, Operating Lease, Lease Not yet Commenced, Number Of Renewal Options

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

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Area of a real estate property.

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

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Amount of distribution received from equity method investee for return on investment, classified as operating activities. Excludes distribution for return of investment, classified as investing activities.

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Amount of income (loss) for proportionate share of equity method investee's income (loss).

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Term of lessor's operating lease renewal for lease not yet commenced, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Term of lessor's operating lease not yet commenced, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of increase (decrease) in other comprehensive income, after tax, from changes classified as other.

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The cash outflow from the acquisition of a piece of land and anything permanently fixed to it, including buildings, structures on it and so forth, and payments to develop real estate assets by adding improvements on or to a parcel of land. Such improvements may include drainage, utilities, subdividing, access, buildings, and any combination of these elements. Including real estate intended to generate income for the owner; excluding real estate acquired for use by the owner.

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Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

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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.

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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.

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Cash received on stock transaction after deduction of issuance costs.

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The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

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Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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Percentage of vesting of award under share-based payment arrangement.

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Related Person Transactions (Details) $ / shares in Units, ft² in Thousands, $ in Thousands		1 Months Ended				12 Months Ended				22 Months Ended
	Jul. 01, 2019 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) ft²	Jun. 30, 2021 USD ($) ft² renewal_option	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2021 USD ($) ft² agreement	Dec. 31, 2020 USD ($) ft²	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2023 USD ($)
Related Party Transaction [Line Items]
Rentable Square Feet (in square feet) \| ft²		926				926	163
Equity in net losses of investees						$ (2,501)	$ (1,193)	$ (1,259)
RMR LLC
Related Party Transaction [Line Items]
Number of agreements with RMR LLC to provide management services \| agreement						2
Rental income earned						$ 1,138	1,120	1,142
Related party transaction							17,358	21,320
AIC
Related Party Transaction [Line Items]
Related party transaction									$ 1,211
Distribution of earnings from Affiliates Insurance Company		$ 11		$ 287	$ 9,000
Amount invested in equity investee							$ 11
Equity in unrealized gain (loss) of investees								281
Equity in net losses of investees								$ 90
Sonesta International Hotels Corporation
Related Party Transaction [Line Items]
Lessor, Operating Lease, Lease Not yet Commenced, Term of Contract			30 years
Rentable Square Feet (in square feet) \| ft²			230
Percentage upon completion of redevelopment			54.00%
Number of renewal options \| renewal_option			2
Renewal term			10 years
Annual base rent			$ 6,436
Deferred payment plan period			18 months
Annual percentage increase			10.00%
Annual base rent increase			5 years
Sonesta International Hotels Corporation \| Forecast
Related Party Transaction [Line Items]
Purchase price										$ 66,000
SIR
Related Party Transaction [Line Items]
Related party transaction									$ 1,666
IPO \| RMR Inc
Related Party Transaction [Line Items]
Number of shares sold (in shares) \| shares	2,801,060
Sale of stock (in dollars per share) \| $ / shares	$ 40.00
Sale of stock, consideration received on transaction	$ 104,674
Officers and Other Employees \| Common Shares \| 2009 Award Plan
Related Party Transaction [Line Items]
Award vesting period						4 years
Officers and Other Employees \| Share-based Payment Arrangement, Tranche 1 \| Common Shares \| 2009 Award Plan
Related Party Transaction [Line Items]
Award vesting rights, percentage						20.00%
Officers and Other Employees \| Share-based Payment Arrangement, Tranche 2 \| Common Shares \| 2009 Award Plan
Related Party Transaction [Line Items]
Award vesting rights, percentage						20.00%
Officers and Other Employees \| Share-based Payment Arrangement, Tranche 3 \| Common Shares \| 2009 Award Plan
Related Party Transaction [Line Items]
Award vesting rights, percentage						20.00%
Officers and Other Employees \| Share-based Compensation Award, Tranche 4 \| Common Shares \| 2009 Award Plan
Related Party Transaction [Line Items]
Award vesting rights, percentage						20.00%
Officers and Other Employees \| Share-based Compensation Award, Tranche 5 \| Common Shares \| 2009 Award Plan
Related Party Transaction [Line Items]
Award vesting rights, percentage						20.00%