Leases (Details)	12 Months Ended
	Apr. 30, 2020
Leases
Option to extend period (in years)	10 years
Option to terminate period (in years)	2 years
Minimum
Leases
Remaining lease terms (in years)	1 year
Maximum
Leases
Remaining lease terms (in years)	6 years
Option to extend period (in years)	10 years