Stock-Based Compensation - Summary of Stock Option Activity (Detail) - Stock Options - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Stock Option Activity
Shares, options outstanding, beginning balance	409,296
Shares, forfeited/expired	(131,334)
Shares, options outstanding, ending balance	277,962	409,296
Weighted Average Exercise Price
Weighted average exercise price, options outstanding (usd per share), beginning balance	$ 19.34
Weighted-average exercise price, forfeited/expired (usd per share)	18.82
Weighted average exercise price, options outstanding (usd per share), ending balance	$ 19.58	$ 19.34
Additional Disclosures
Weighted average remaining contractual term options outstanding (years)	1 year 9 months 18 days	2 years 4 months 24 days
Aggregate intrinsic value, options outstanding	$ 0.0	$ 0.0

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- Definition

For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

+ References

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Weighted average price of options that were either forfeited or expired.

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- Definition

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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- Definition

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

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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- Definition

Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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