Income Taxes (Schedule Of Effective Income Tax Rate Reconciliation) (Details) - USD ($)	12 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016
Income Tax Disclosure [Abstract]
Federal statutory rate	30.40%	35.00%	35.00%
Federal income tax credits	(0.50%)	(0.20%)	(0.00%)
Acquisition and integration costs	1.20%	0.00%	0.00%
Stock compensation	(2.40%)	(1.30%)	(0.00%)
Meals and entertainment	0.30%	0.30%	0.30%
Effect of Tax Act	1.20%	(0.00%)	(0.00%)
Domestic production deduction	(0.80%)	(2.20%)	(2.50%)
Other	0.40%	(0.30%)	(0.10%)
Total	(0.60%)	(3.70%)	(2.30%)
Effective federal income tax rate	29.80%	31.30%	32.70%
State income taxes, net of federal tax effect	3.60%	3.30%	3.30%
Effective income tax rate	33.40%	34.60%	36.00%
Income taxes paid