Leases (Details 3) - USD ($) $ in Millions	Apr. 30, 2021	Apr. 30, 2020
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2022	$ 44.2
2023	40.9
2024	29.2
2025	21.3
2026	18.7
2027 and beyond	7.9
Total undiscounted minimum lease payments	162.2
Less: Imputed interest	8.3
Lease liabilities	153.9	$ 156.5
Finance Lease, Liability, Payment, Due [Abstract]
2022	1.9
2023	1.2
2024	0.9
2025	0.4
2026	0.1
2027 and beyond	0.0
Total undiscounted minimum lease payments	4.5
Less: Imputed interest	0.2
Lease liabilities	$ 4.3	$ 5.7