Customer Receivables (Components Of Customer Receivables ) (Details) - USD ($) $ in Thousands	Jan. 31, 2021	Apr. 30, 2020
Accounts Receivable, after Allowance for Credit Loss [Abstract]
Gross customer receivables	$ 156,732	$ 112,528
Less:
Allowance for doubtful accounts	(371)	(472)
Allowance for returns and discounts	(8,527)	(5,712)
Net customer receivables	$ 147,834	$ 106,344

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant