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

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

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

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

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

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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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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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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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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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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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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest exercisable or convertible options. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Percentage of vesting of award under share-based payment arrangement.

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Amount of stock repurchase plan authorized.

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Expiration date for the purchase of an entity's own shares under a stock repurchase plan, in the CCYY-MM-DD format.

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Number of shares that have been repurchased during the period and are being held in treasury.

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Stockholders' Equity - Additional Information (Detail)		3 Months Ended		9 Months Ended
Stockholders' Equity - Additional Information (Detail)	Dec. 15, 2020 USD ($) shares	Jan. 31, 2021 USD ($) shares	Jan. 31, 2020 USD ($) shares	Jan. 31, 2021 USD ($) OptionPlan shares	Jan. 31, 2020 USD ($) shares	Mar. 02, 2021 USD ($)	Apr. 30, 2020 shares	Apr. 30, 2019 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program Completion date	Jan. 31, 2021
Antidilutive shares excluded from computation of diluted earnings per share		14,994	20,664	16,724	24,843
Number of stock incentive plans \| OptionPlan				2
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number		0	92,094	0	92,094		200,667	267,761
Intrinsic value of stock outstanding \| $			$ 571,000		$ 571,000
Intrinsic value of stock exercisable \| $			571,000		571,000
Intrinsic value of stock exercised \| $		$ 151,000	100,000	$ 2,900,000	100,000
Unrecognized compensation expense relating to outstanding stock options \| $		$ 0	0	0	0
Stock-based compensation expense \| $				$ 3,400,000	$ 941,000
Performance period				3 years
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				4 years
Vesting, percentage				0.25%
Stock units, awarded				234,007	255,911
Grant date fair value of vested RSUs and PSUs \| $				$ 7,000,000.0	$ 2,200,000
Stock units, forfeited				88,219	236,319
RSUs \| Non-Executive Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units, awarded				139,976	140,271
RSUs \| Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units, awarded				25,570	115,640
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units, forfeited				92,500	156,725
Performance Shares \| Executive Officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units, awarded				36,308
Stock units, forfeited				92,500
RSUs and PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense \| $				$ 2,600,000	$ 789,000
Stock units, awarded				270,315	255,911
Stock units, forfeited				180,719	603,344
Unrecognized compensation expense related to unvested RSUs and PSUs \| $			$ 4,000,000.0		$ 4,000,000.0
Weighted average remaining contractual term					1 year 4 months 24 days
Service based PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units, forfeited					210,300
2013 Incentive Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				4 years
Stock option, exercisable period				10 years
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares repurchased	2,737,489
Cash on hand utilized for repurchase of shares \| $	$ 50,000,000.0
Common Stock \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized repurchase amount \| $	$ 50,000,000.0
Common Stock \| Maximum \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized repurchase amount \| $						$ 100,000,000.0