Share-based Compensation - Summary of SARs Activity (Detail) - Stock-Settled SARs Activity	9 Months Ended
Sep. 30, 2020 $ / shares shares
Shares
Outstanding, beginning balance (in shares) \| shares	625,368
Exercised (in shares) \| shares	(418,702)
Expired or forfeited (in shares) \| shares	(15,031)
Outstanding, ending balance (in shares) \| shares	191,635
Weighted-Average Exercise Price
Outstanding, beginning balance (in dollars per share) \| $ / shares	$ 33.60
Exercised (in dollars per share) \| $ / shares	32.25
Expired or forfeited (in dollars per share) \| $ / shares	0
Outstanding, ending balance (in dollars per share) \| $ / shares	$ 36.21

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.

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

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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- Definition

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

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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

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