Number of equity incentive plans.

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- Definition

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

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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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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 options outstanding, including both vested and non-vested options.

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- Definition

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

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Number of share options (or share units) exercised during the current period.

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Restricted Stock and Stock Options - Additional Information (Detail) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($) shares	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) Incentive_Plan shares	Sep. 30, 2020 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity incentive plans \| Incentive_Plan			2
Market value of shares \| $			$ 2.2	$ 1.8
Stock options exercised, Shares			0	0
Stock options outstanding	0		0
Share-based compensation expense \| $	$ 0.4	$ 0.8	$ 1.7	$ 2.6
Restricted Stock [Member] \| Non-employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued, shares			8,707	5,269
Performance Awards [Member] \| Non-employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued, shares			24,288	23,207