The number of facilities closed.

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Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

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Business, Basis of Presentation and Summary of Significant Accounting Policies - Restructuring charges (Details) $ in Millions	3 Months Ended		12 Months Ended
	Apr. 30, 2020 USD ($) facility	Jul. 31, 2018 USD ($)	Apr. 30, 2021 USD ($)
Restructuring Cost and Reserve [Line Items]
Number of facilities closed \| facility	1
Restructuring costs	$ 2.2
Impairment	1.9		$ 1.0
Severance	$ 0.3
Selling, general and administrative expenses
Restructuring Cost and Reserve [Line Items]
Restructuring costs		$ 5.0