Percentage of average return on invested capital on share based compensation arrangement.

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Reduced percentage of restricted shares.

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Reduced percentage of shares earned in stock option plan.

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Share based compensation arrangement by share based payment award equity instruments other than options vesting date.

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- Definition

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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- Definition

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

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- Definition

Amount of noncash expense for award of restricted stock or unit under share-based payment arrangement.

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- Definition

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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Description of terms of share-based payment arrangement. Includes, but is not limited to, type of award or grantee and reason for issuance.

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Date the equity-based award expires, in YYYY-MM-DD format.

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- Definition

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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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

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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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Gross number of share options (or share units) granted during the period.

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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

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Amount of noncash expense for option under share-based payment arrangement.

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Share-Based Employee Compensation - Additional Information (Detail) - USD ($) $ in Millions		1 Months Ended		3 Months Ended			6 Months Ended
	Jul. 19, 2021	Aug. 31, 2022	May 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Aug. 07, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future grant				3,260,318			3,260,318		3,000,000
Stock option expense					$ 1.1	$ 1.0	$ 1.9	$ 1.7
Aggregate intrinsic value for outstanding options				$ 10.3			10.3
Aggregate intrinsic value for exercisable options				5.6			5.6
Total intrinsic value of options exercised							1.0
Restricted stock or unit expense				3.3		$ 2.9	7.6	$ 4.7
Unrecognized compensation cost				$ 4.8			$ 4.8
Options granted							56,621
Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future grant									1,500,000
Performance Vesting Stock Options [Member] \| Long Term Compensation Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future grant				25,192			25,192
Reduced percentage of shares earned in stock options plan							66.70%
Stock based compensation plan, description							The performance criteria for the Fiscal 2023 Employee Performance Stock Option Award are based upon the achievement of certain levels of return on equity (as defined in the option agreement), ranging from 10.0% to 20.0%, for the fiscal year ending March 31, 2023. All stock options will be earned if the return on equity is 20.0% or greater, and the percentage of shares earned will be reduced proportionately to approximately 66.7% if the return on equity is 10.0%. If the Company does not achieve a return on equity of at least 10.0%, all granted stock options will be forfeited.
Share-based compensation vesting period			4 years
Share-based compensation award expiration term			10 years
Performance Vesting Stock Options [Member] \| Long Term Compensation Plan [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of average return on invested capital			10.00%
Share-based compensation expiration date							Mar. 31, 2024
Performance Vesting Stock Options [Member] \| Long Term Compensation Plan [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of average return on invested capital			20.00%
Share-based compensation expiration date							Mar. 31, 2026
Time Vesting Stock Options [Member] \| Long Term Compensation Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future grant			20,994
Share-based compensation vesting period			4 years
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average period of recognition of unrecognized compensation cost							2 years 4 months 24 days
Stock Options [Member] \| Long Term Compensation Plan [Member] \| Board of Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation award expiration term		10 years
Options granted		3,510
Performance Vesting Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future grant			50,783
Stock based compensation plan, description							The performance criteria for the Fiscal 2023 Employee Restricted Stock Performance Award are based upon the achievement of certain levels of return on equity (as defined in the award agreement), ranging from 10.0% to 20.0%, for the fiscal year ending March 31, 2023. All restricted shares will be earned if the return on equity is 20.0% or greater, and the percentage of shares earned will be reduced proportionately to approximately 66.7% if the return on equity is 10.0%. If the Company does not achieve a return on equity of at least 10.0%, all awards will be forfeited.
Share-based compensation vesting period			4 years
Share-based compensation vesting date			Mar. 31, 2026
Reduced percentage of restricted shares							66.70%
Performance Vesting Restricted Stock [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of average return on invested capital			10.00%
Share-based compensation vesting date			Mar. 31, 2024
Performance Vesting Restricted Stock [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of average return on invested capital			20.00%
Time Vesting Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future grant			42,545
Share-based compensation vesting period	4 years		4 years
Time Vesting Restricted Stock [Member] \| Board of Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation vesting period			6 months
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation vesting period		6 months
Weighted-average period of recognition of unrecognized compensation cost							2 years 6 months
Unrecognized compensation cost				$ 23.7			$ 23.7
Restricted Stock [Member] \| Board of Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future grant		14,482