Stock Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017	Apr. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 20.07
Shares authorized	3,596,805		3,596,805
Shares reserved for future issuance	4,478,958		4,478,958
Share-based compensation expense	$ 2,051	$ 1,678	$ 7,445	$ 6,247
Share-based compensation expense (net of tax)	1,272	$ 1,040	4,616	$ 3,873
Unrecognized compensation cost related to share-based compensation, pre tax	$ 15,840		$ 15,840
Weighted average period remaining			2 years
Options Outstanding, Exercisable	1,882,244	2,679,527	1,882,244	2,679,527
Options Outstanding, Exercisable, Weighted Average Exercise Price	$ 28.37	$ 30.09	$ 28.37	$ 30.09
Proceeds from stock options exercised	$ 4,015	$ 610	$ 18,674	$ 663
Tax benefit on stock options exercised	1,514	37	2,967	40
Intrinsic value of stock options exercised	7,809	105
Fair value of stock options vested	2,901	$ 3,193
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value			4	$ 1
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested	$ 26		$ 26
Service Based Restricted Shares and Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 35.13