Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Apr. 30, 2025	Apr. 30, 2024	Apr. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 29.9	$ 23.9	$ 25.6
Related income tax benefit	7.1	5.6	6.0
Selling, Distribution And Administrative Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	29.1	23.7	25.6
Other special project costs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 0.8	$ 0.2	$ 0.0