Income Taxes (Schedule Of Reconciliation Between Income Tax Provision And Statutory Federal Tax Rate) (Details)	12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2015
Income Tax Disclosure [Abstract]
Document Fiscal Year Focus	2017
U.S. statutory tax rate	35.00%	35.00%	35.00%
State income taxes, net of federal income tax benefit	1.60%	2.20%	3.50%
Earnings taxed in foreign jurisdictions	(4.60%)	(2.00%)	(1.80%)
Permanent differences	(0.40%)	(0.20%)	(0.30%)
Uncertain tax positions	4.30%	2.80%	(1.00%)
Change in valuation allowance	0.20%	(0.50%)	0.20%
Currency loss on previously taxed income	(1.60%)	(0.00%)	(0.00%)
Significant state apportionment changes	0.00%	(4.30%)	0.00%
Other	(1.40%)	(0.30%)	(1.10%)
Effective tax rate	33.10%	32.70%	34.50%