Share-based compensation arrangement by share-based payment award percentage of target achieved.

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- Definition

Share-based compensation arrangement by share based payment award performance period.

+ References

No definition available.

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- Definition

Share based compensation expense reversed.

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- Definition

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

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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 cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

+ References

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- Definition

Amount of cost to be recognized for option under share-based payment arrangement.

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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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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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

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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- Definition

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

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Stock-Based Compensation - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Share-Based Payment Arrangement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)				13,420	25,066
Recognized stock-based compensation expense				$ 500,000	$ 500,000
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)				313,502
Recognized stock-based compensation expense	$ 1,200,000	$ 200,000		$ 3,300,000	800,000
Unrecognized stock-based compensation costs	8,200,000			$ 8,200,000
Weighted average remaining recognition period of unrecognized stock-based compensation costs				1 year 8 months 12 days
Restricted Stock Units \| Executive Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)				160,843
Vesting period				2 years
Restricted Stock Units \| Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)				152,659
Vesting period				3 years
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)				50,868
Recognized stock-based compensation expense	$ 300,000	$ (400,000)		$ 700,000	(3,500,000)
Weighted average remaining recognition period of unrecognized stock-based compensation costs				2 years 2 months 12 days
Maximum number of shares of common stock available for awards (in shares)	101,736			101,736
Share-based compensation arrangement by share-based payment award percentage of target achieved						95.00%
Unrecognized compensation costs	$ 2,800,000			$ 2,800,000
Performance Share Units \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation costs						$ 14,100,000	$ 14,100,000
Performance Share Units \| Executive Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)				50,868
Share-based compensation arrangement by share based payment award performance period				3 years
2019 Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	0			$ 0
Reversed of expense related to PSU's					$ 1,400,000
2018 Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reversed of expense related to PSU's			$ 1,800,000
2020 Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	$ 0			$ 0