Equity Award, Conversion Basis

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- Definition

Number of Tranches

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- Definition

Represents the number of trustees serving in the board of trustees of the reporting entity.

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- Definition

Share-based Compensation Arrangement, Plan Term

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- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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- Definition

Amount of additional cost recognized for award under share-based payment arrangement from occurrence of event accelerating recognition of cost.

+ References

No definition available.

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- Definition

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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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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- Definition

Agreed-upon price for the exchange of the underlying asset relating to the share-based payment award.

+ References

No definition available.

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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.

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No definition available.

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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

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

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- Definition

Number of shares issued during the period as a result of the conversion of convertible securities.

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- Definition

Aggregate value of stock related to Restricted Stock Awards issued during the period.

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Value, before forfeiture, of shares issued under share-based payment arrangement. Excludes employee stock ownership plan (ESOP).

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Share-Based Compensation - Narrative (Details) $ / shares in Units, $ in Thousands										12 Months Ended
	Sep. 16, 2020 USD ($) $ / shares shares	Jun. 23, 2020 USD ($) trustee $ / shares shares	Jan. 27, 2020 $ / shares shares	Jun. 20, 2019 USD ($) trustee $ / shares shares	Jan. 29, 2019 $ / shares shares	Oct. 28, 2018 shares	Jun. 20, 2018 USD ($) trustee $ / shares shares	Jan. 29, 2018 $ / shares shares	Jun. 16, 2015	Dec. 31, 2024 shares	Dec. 31, 2023 shares	Dec. 31, 2022 shares	Dec. 31, 2021 shares	Dec. 31, 2020 USD ($) tranche $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares available for issuance (in shares)														2,291,152
Common stock issued (in shares)						225,655								121,522,555	121,924,199
Compensation expense, accelerated vesting due to a staffing reduction \| $														$ 17	$ 800	$ 400
Equity Commonwealth 2015 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)				2,500,000
Share-based compensation arrangement, plan term									10 years
General and administrative expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense \| $														$ 13,200	$ 14,400	$ 19,700
Restricted shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period														4 years
Common stock issued (in shares)														388,615
Stock issued during period, value \| $	$ 100
Number of equity awards granted (in shares)	2,526	19,104	85,058	2,940	112,359		25,600	125,409
Granted (in dollars per share) \| $ / shares	$ 30.39		$ 32.81		$ 31.77			$ 29.78
Number of independent trustees \| trustee		9		9			9
Share based compensation amount \| $				$ 100			$ 100
Price per share (in dollars per share) \| $ / shares		$ 31.41		$ 34.01			$ 31.25
Restricted shares \| Independent Trustee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity awards granted (in shares)				23,520			3,200
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period														3 years
Number of tranches \| tranche														2
Vested (in shares)						225,655								388,615	384,811
Common stock issued (in shares)															384,811
RSUs \| Vesting in three years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage														50.00%
RSUs \| Vesting in four years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period														1 year
Vesting percentage														50.00%
RSUs, target
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity awards granted (in shares)			172,697		228,128			254,615
RSUs, maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity awards granted (in shares)			430,447		568,609			634,628
LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity award, conversion basis														1
Number of equity awards granted (in shares)				2,940
Time-Based LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity awards granted (in shares)		9,552					3,200
Time-Based LTIP Units \| Independent Trustee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity awards granted (in shares)		3,184
Time-Based LTIP Units, target
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity awards granted (in shares)			20,116
Market-Based LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares)														84,754
Conversion of equity instruments (in shares)														(84,754)
Market-Based LTIP Units, target
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity awards granted (in shares)			40,841
Market-Based LTIP Units, maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity awards granted (in shares)			101,796
OP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Conversion of equity instruments (in shares)														84,754
Restricted Shares and Time-Based LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		1 year
Vested (in shares)														149,103	164,074	407,273
Number of equity awards granted (in shares)														136,356	138,819	154,209
Granted (in dollars per share) \| $ / shares														$ 32.47	$ 32.20	$ 30.05
Share based compensation amount \| $		$ 100
Unvested (in shares)														385,688	400,314	425,888	678,952
Estimated future compensation expense for unvested shares \| $														$ 5,900
Weighted average period over which compensation expense will be recorded														2 years 2 months 12 days
Restricted Shares and Time-Based LTIP Units \| Scenario, Forecast
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares)										52,568	80,505	112,986	139,629
RSUs and Market-Based LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares)														473,369	384,811	367,260
Number of equity awards granted (in shares)														532,243	568,609	634,628
Granted (in dollars per share) \| $ / shares														$ 16.12	$ 15.91	$ 14.90
Unvested (in shares)														1,964,918	2,003,175	2,046,644	2,131,947
Estimated future compensation expense for unvested shares \| $														$ 11,500
Weighted average period over which compensation expense will be recorded														2 years 1 month 6 days
Maximum \| Equity Commonwealth 2015 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares available for issuance (in shares)														5,750,000