Long-Term Debt - Schedule of Long-term Debt, at Amortized Cost (Detail) - USD ($) $ in Thousands	Apr. 30, 2021	Apr. 30, 2020
Debt Instrument [Line Items]
Long-term borrowings, net of unamortized discount and debt issuance costs	$ 394,794	$ 394,144
4.625% Senior Unsecured Notes due 2027
Debt Instrument [Line Items]
Less: Unamortized discount and issuance costs	(5,206)	(5,856)
Long-term borrowings, net of unamortized discount and debt issuance costs	394,794	394,144
4.625% Senior Unsecured Notes due 2027 \| Senior Unsecured Notes
Debt Instrument [Line Items]
Long-term debt	$ 400,000	$ 400,000

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
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-Section S99
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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 unamortized debt discount (premium) and debt issuance costs.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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