Supplementary Balance Sheet Information (Components Of Accounts Payable And Accrued Liabilities) (Details) - USD ($) $ in Thousands	Jul. 31, 2020	Aug. 01, 2019	Jul. 31, 2019
Trade payables	$ 59,692		$ 96,377
Deferred Revenue, Current	256,402		335,669
Accrued salaries, wages and deferred compensation	25,588		50,318
Accrued benefits	43,704		37,797
Deposits	20,070		32,108
Operating Lease, Liability, Current	36,604	$ 34,900	0
Other accruals	57,048		55,588
Total accounts payable and accrued liabilities	$ 499,108		$ 607,857