Computation of Basic and Diluted Net Income Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Jul. 31, 2014		Jul. 31, 2013		Jul. 31, 2012
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Net income	$ 34,480		$ 31,121		$ 43,071
Weighted average number of common shares outstanding-basic	12,404		12,247		12,265
Effect of dilutive securities:
Stock options and RSUs	263		322		311
Weighted average number of common shares outstanding-diluted	12,667		12,569		12,576
Basic net income per share	$ 2.78		$ 2.54		$ 3.51
Diluted net income per share	$ 2.72		$ 2.48		$ 3.42
Anti-dilutive shares related to outstanding stock options and unvested restricted stock	118	[1]	105	[1]	212	[1]

[1] These shares related to outstanding stock options and unvested restricted stock were not included in our calculations of diluted earnings per share, as the effect of including them would be anti-dilutive.