Supplementary Balance Sheet Information (Components Of Accounts Payable And Accrued Liabilities) (Details) - USD ($) $ in Thousands	Apr. 30, 2021	Jul. 31, 2020	Apr. 30, 2020
Balance Sheet Related Disclosures [Abstract]
Trade payables	$ 64,412	$ 59,692	$ 62,101
Deferred revenue	238,075	256,402	219,395
Accrued salaries, wages and deferred compensation	69,821	25,588	16,184
Accrued benefits	49,958	43,704	44,536
Deposits	35,263	20,070	27,053
Operating Lease, Liability, Current	37,687	36,604	34,996
Other liabilities	72,048	57,048	45,009
Total accounts payable and accrued liabilities	$ 567,264	$ 499,108	$ 449,274