Transactions With Related Parties (Details) - USD ($) $ in Millions	12 Months Ended
Apr. 30, 2021	Apr. 30, 2020
Southern Wall Products, Inc. \| Inventory purchases
Related Party Transaction [Line Items]
Purchases from related party	$ 7.3	$ 14.3

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.

No definition available.

Name:	us-gaap_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration