Supplementary Balance Sheet Information (Components Of Accounts Payable And Accrued Liabilities) (Details) - USD ($) $ in Thousands	Jan. 31, 2019	Jul. 31, 2018	Jan. 31, 2018
Balance Sheet Related Disclosures [Abstract]
Trade payables	$ 106,183	$ 80,793	$ 94,680
Deferred revenue	346,356	282,103	292,336
Accrued salaries, wages and deferred compensation	66,090	40,034	52,329
Accrued benefits	37,991	33,963	35,109
Deposits	52,867	26,646	43,457
Other liabilities	76,249	40,994	70,652
Total accounts payable and accrued liabilities	$ 685,736	$ 504,533	$ 588,563