Supplementary Balance Sheet Information (Components Of Accounts Payable And Accrued Liabilities) (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Jul. 31, 2018	Oct. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Trade payables	$ 118,648	$ 80,793	$ 103,540
Deferred revenue	450,300	282,103	407,848
Accrued salaries, wages and deferred compensation	20,961	40,034	19,699
Accrued benefits	30,712	33,963	30,317
Deposits	34,479	26,646	21,017
Other liabilities	48,533	40,994	48,046
Total accounts payable and accrued liabilities	$ 703,633	$ 504,533	$ 630,467