Business, Basis of Presentation and Summary of Significant Accounting Policies - Selling, General and Administrative Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Shipping and Handling Cost [Line Items]
Cost of sales	$ 2,236,120	$ 2,178,093	$ 2,111,913
Delivery \| Selling, general and administrative expenses
Shipping and Handling Cost [Line Items]
Cost of sales	$ 232,800	$ 243,000	$ 225,600

Cost of product sold and service rendered, excluding depreciation, depletion, and amortization.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(2)(a))
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(2)(d))
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration