Supplementary Balance Sheet Information (Components Of Accounts Payable And Accrued Liabilities) (Details) - USD ($) $ in Thousands	Jul. 31, 2018	Jul. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Trade payables	$ 80,793	$ 71,558
Deferred revenue	282,103	240,096
Accrued salaries, wages and deferred compensation	40,034	44,869
Accrued benefits	33,963	32,505
Deposits	26,646	23,742
Other accruals	40,994	54,899
Total accounts payable and accrued liabilities	$ 504,533	$ 467,669