Share-Based Payments - Narrative (Details) - USD ($) $ / shares in Units, $ 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]
Shares available for future issuance	3,389,099
Vesting period for share-based payments	3 years
Closing market price (in dollars per share)	$ 116.27
Share-based compensation expense	$ 29.9	$ 23.9	$ 25.6
Related income tax benefit	7.1	5.6	6.0
Cash received from option exercises	1.9	3.2	21.6
Equity instruments other than options vested in period weighted average grant date fair value total value	27.7	36.5	30.6
Fair value of equity awards other than stock options vesting	$ 25.7	$ 46.9	$ 36.2
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted in period gross	0	84,568	113,970
Forfeiture period for share-based payments	10 years
Aggregate intrinsic value - outstanding	$ 1.4
Aggregate intrinsic value - exercisable	$ 1.4
Average remaining contractual term - outstanding	5 years 8 months 12 days
Average remaining contractual term - exercisable	5 years 3 months 18 days
Intrinsic value of options exercised	$ 0.1	$ 0.1	$ 8.6
Share-based compensation expense	1.9	2.8	3.1
Related income tax benefit	0.4	$ 0.7	$ 0.7
Unrecognized compensation expense	$ 1.1
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Requisite service period for share-based payments	3 years
Restricted Shares And Deferred Stock Units 2024, 2023, and 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Requisite service period for share-based payments	3 years