Leases (Details 4)	Apr. 30, 2021	Apr. 30, 2020
Leases [Abstract]
Operating leases, Weighted average remaining lease term	4 years 4 months 24 days	4 years 8 months 12 days
Finance leases, Weighted average remaining lease term	3 years 1 month 6 days	3 years 4 months 24 days
Operating leases, Weighted average discount rate	2.50%	3.10%
Finance leases, Weighted average discount rate	2.60%	2.90%