Income Taxes (Schedule Of Reconciliation Between Income Tax Provision And Statutory Federal Tax Rate) (Details)	12 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Income Tax Disclosure [Abstract]
Document Fiscal Year Focus	2016
U.S. statutory tax rate	35.00%	35.00%	35.00%
State income taxes, net of federal income tax benefit	2.20%	3.50%	3.80%
Earnings taxed in foreign jurisdictions	(2.00%)	(1.80%)	(0.20%)
Permanent differences	(0.20%)	(0.30%)	0.10%
Uncertain tax positions	(2.80%)	1.00%	5.60%
Change in valuation allowance	(0.50%)	0.20%	1.50%
Effective Income Tax Rate Reconciliation, Tax Contingency, State and Local, Percent	(4.30%)	0.00%	0.00%
Other	(0.30%)	(1.10%)	0.20%
Effective tax rate	32.70%	34.50%	34.80%