Supplementary Balance Sheet Information (Components Of Accounts Payable And Accrued Liabilities) (Details) - USD ($) $ in Thousands	Oct. 31, 2016	Jul. 31, 2016	Oct. 31, 2015
Balance Sheet Related Disclosures [Abstract]
Trade payables	$ 90,773	$ 72,658	$ 101,016
Deferred revenue	328,009	182,506	240,288
Accrued salaries, wages and deferred compensation	29,544	43,086	11,878
Accrued benefits	28,564	29,175	22,818
Deposits	18,418	23,307	15,979
Other accruals	47,615	46,756	46,858
Total accounts payable and accrued liabilities	$ 542,923	$ 397,488	$ 438,837