Supplementary Balance Sheet Information (Components Of Accounts Payable And Accrued Liabilities) (Details) - USD ($) $ in Thousands	Jan. 31, 2017	Jul. 31, 2016	Jan. 31, 2016
Balance Sheet Related Disclosures [Abstract]
Trade payables	$ 88,814	$ 72,658	$ 82,913
Deferred revenue	259,212	182,506	190,976
Accrued salaries, wages and deferred compensation	50,923	43,086	43,916
Accrued benefits	32,269	29,175	26,199
Deposits	42,024	23,307	36,995
Other liabilities	68,093	46,756	66,771
Total accounts payable and accrued liabilities	$ 541,335	$ 397,488	$ 447,770