Supplementary Balance Sheet Information (Components Of Accounts Payable And Accrued Liabilities) (Details) - USD ($) $ in Thousands	Jan. 31, 2021	Jul. 31, 2020	Jan. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Trade payables	$ 86,251	$ 59,692	$ 126,836
Deferred revenue	480,353	256,402	426,672
Accrued salaries, wages and deferred compensation	59,665	25,588	48,591
Accrued benefits	44,549	43,704	46,622
Deposits	31,472	20,070	63,432
Operating Lease, Liability, Current	36,878	36,604	35,650
Other liabilities	92,626	57,048	63,694
Total accounts payable and accrued liabilities	$ 831,794	$ 499,108	$ 811,497