Valuation And Qualifying Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Allowance for Doubtful Accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 599	$ 616	$ 728
Charged to Costs and Expenses	200	26	112
Deductions	(455)	(43)	(224)
Balance at End of Period	344	599	616
Valuation Allowance of Deferred Tax Assets
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	5,167	4,890	4,109
Charged to Costs and Expenses	518	506	781
Deductions	(148)	(229)
Balance at End of Period	$ 5,537	$ 5,167	$ 4,890