Summary of Allowance for Doubtful Accounts Activity (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Summary Of Significant Accounting Policies [Line Items]
Beginning Balance	$ 549	$ 422	$ 302
Net charged to expense	32	3	195
Write-offs net of recoveries/payments	(54)	(116)	(75)
Heartland acquisition		240
Ending Balance	$ 527	$ 549	$ 422