Income Taxes (Schedule Of Effective Income Tax Rate Reconciliation) (Details)	12 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2018
Income Tax Disclosure [Abstract]
Federal statutory rate	21.00%	21.00%	30.40%
Federal income tax credits	(0.90%)	(1.40%)	(0.50%)
Acquisition and integration costs	0.00%	0.00%	1.20%
Stock compensation	(0.10%)	(0.50%)	(2.40%)
Meals and entertainment	0.30%	0.30%	0.30%
Effect of Tax Act	0.00%	(1.10%)	1.20%
Domestic production deduction	0.00%	0.00%	(0.80%)
Valuation allowance for deferred taxes	0.70%	0.60%	0.00%
Foreign	0.40%	0.80%	0.00%
Other	0.70%	1.20%	0.40%
Total	1.10%	(0.10%)	(0.60%)
Effective federal income tax rate	22.10%	20.90%	29.80%
State income taxes, net of federal tax effect	3.40%	3.60%	3.60%
Effective income tax rate	25.50%	24.50%	33.40%