Leases (Other Information Related to Operating Leases) (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Leases [Abstract]
Rent expense			$ 255,000
Cash paid for operating lease costs	$ 240,299	$ 223,080
Operating lease right of use assets obtained in exchange for operating lease liabilities	$ 167,827	$ 345,079
Weighted-average remaining operating lease term (years)	3 years	3 years
Weighted-average operating lease discount rate	3.00%	3.30%