Supplementary Balance Sheet Information (Components Of Accounts Payable And Accrued Liabilities) (Details) - USD ($) $ in Thousands	Jul. 31, 2017	Jul. 31, 2016
Balance Sheet Related Disclosures [Abstract]
Trade payables	$ 71,558	$ 72,658
Deferred revenue	240,096	182,506
Accrued salaries, wages and deferred compensation	44,869	43,086
Accrued benefits	32,505	29,175
Deposits	23,742	23,307
Other accruals	54,899	46,756
Total accounts payable and accrued liabilities	$ 467,669	$ 397,488