Income Taxes (Schedule Of Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Millions	12 Months Ended
	Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2013
Income Tax Disclosure [Abstract]
Federal statutory rate	35.00%	35.00%	35.00%
Research and experimentation tax credit	(2.30%)	(0.00%)	(0.00%)
Meals and entertainment	0.50%	0.80%	1.50%
Domestic production deduction	(2.40%)	(1.80%)	(0.30%)
Other	0.10%	0.70%	1.40%
Total	(4.10%)	(0.30%)	2.60%
Effective federal income tax rate	30.90%	34.70%	37.60%
State income taxes, net of federal tax effect	3.80%	4.50%	4.10%
Effective income tax rate	34.70%	39.20%	41.70%
Income taxes paid	$ 13.3	$ 4.3	$ 1.2