Income Taxes (Schedule Of Reconciliation Of U.S. Statutory Income Tax Rate With Effective Income Tax Rate) (Details)	12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Income Tax Disclosure [Abstract]
Statutory U.S. federal rate (percentage)	26.90%	35.00%	35.00%
State income taxes (percentage)	0.90%	0.90%	0.80%
Foreign operations (percentage)	1.70%	(8.30%)	(8.10%)
Export, manufacturing and research credits (percentage)	(1.00%)	(1.10%)	(1.60%)
Change in unrecognized tax benefits (percentage)	(0.30%)	1.00%	(1.00%)
Tax benefits on stock-based compensation (percentage)	(1.20%)	(0.00%)	(0.00%)
Impact of U.S. Tax Cuts and Jobs Act (percentage)	23.20%	0.00%	0.00%
Other (percentage)	0.20%	0.20%	0.80%
Effective income tax rate (percentage)	50.40%	27.70%	25.90%