Stock Options and Share-Based Compensation - Summary of Stock Option Activity and Weighted Average Exercise Price (Detail) - $ / shares	12 Months Ended
Apr. 30, 2023	Apr. 30, 2022	Apr. 30, 2021
Number of Shares
Outstanding at beginning of year (in shares)	47,400	84,300
Canceled (in shares)	(7,850)	(35,400)
Exercised (in shares)	(5,650)	(1,500)
Outstanding at end of year (in shares)	33,900	47,400
Exercisable at end of year (in shares)	33,900	47,400
Weighted Average Exercise Price
Outstanding at beginning of year (in dollar per shares)	$ 19.97	$ 19.34	$ 18.56
Canceled (in dollar per shares)	20.08	17.94
Exercised (in dollar per shares)	14.54	8.59
Outstanding at end of year (in dollar per shares)	19.97	19.34	$ 18.56
Exercisable at end of year (in dollar per shares)	$ 19.97	$ 19.34

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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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.

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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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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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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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

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