Income Taxes (Schedule Of Temporary Differences That Give Rise To Deferred Tax Assets And Liabilities) (Details) (USD $) In Thousands	Jul. 31, 2011	Jul. 31, 2010
Income Taxes
Accrued expenses	$ 12,243	$ 9,130
Compensation and retirement plans	33,298	39,438
Tax credit and NOL carryforwards	1,173	954
Inventory reserves	9,545	8,324
Other	3,311	1,846
Deferred tax assets:	59,570	59,692
Valuation allowance	(692)	(604)
Net deferred tax assets	58,878	59,088
Depreciation and amortization	(37,112)	(30,248)
Other	(1,119)	(1,420)
Deferred tax liabilities	(38,231)	(31,668)
Net deferred tax asset	$ 20,647	$ 27,420