Income Taxes (Schedule Of Effective Income Tax Rate Reconciliation) (Details)	12 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2017
Income Tax Disclosure [Abstract]
Federal statutory rate	21.00%	30.40%	35.00%
Federal income tax credits	(1.40%)	(0.50%)	(0.20%)
Acquisition and integration costs	0.00%	1.20%	0.00%
Stock compensation	(0.50%)	(2.40%)	(1.30%)
Meals and entertainment	0.30%	0.30%	0.30%
Effect of Tax Act	(1.10%)	1.20%	(0.00%)
Domestic production deduction	0.00%	(0.80%)	(2.20%)
Valuation allowance for deferred taxes	0.60%	0.00%	0.00%
Foreign	0.80%	0.00%	0.00%
Other	1.20%	0.40%	(0.30%)
Total	(0.10%)	(0.60%)	(3.70%)
Effective federal income tax rate	20.90%	29.80%	31.30%
State income taxes, net of federal tax effect	3.60%	3.60%	3.30%
Effective income tax rate	24.50%	33.40%	34.60%