Stock-Based Compensation - Summary of Activity under Company's Share-Based Compensation Plans (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jan. 31, 2017	Jan. 31, 2016
Summary of Stock Option Activity [Abstract]
Options Outstanding at July 31, 2014	3,714,039
Options Outstanding at July 31, 2014, Weighted Average Exercise Price	$ 27.34
Options, Grants in Period	378,015
Options, Grants in Period, Weighted Average Exercise Price	$ 35.13	$ 20.02
Options, Exercised in Period	(699,866)
Options, Exercised in Period, Weighted Average Exercise Price	$ 26.65
Options, Forfeitures and Expirations in Period	(292,529)
Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 35.55
Options Outstanding at January 31, 2015	3,099,659
Options Outstanding at January 31, 2015, Weighted Average Exercise Price	$ 27.67
Options Outstanding, Exercisable, Weighted Average Exercise Price	$ 28.67	$ 30.00
Options Outstanding, Weighted Average Remaining Contractual Term	6 years 2 months 12 days
Options Outstanding, Aggregate Intrinsic Value	$ 26,084,674
Options Outstanding, Exercisable, Weighted Average Remaining Contractual Term	4 years 8 months 12 days
Options Outstanding, Exercisable, Aggregate Intrinsic Value	$ 15,296,818
Summary of Service-Based Restricted Stock Unit and Restricted Share Activity [Abstract]
Service-Based RSUs and Restricted Shares, Grants in Period, Weighted Average Grant Date Fair Value	$ 20.07
Performance Based Restricted Shares and Restricted Stock Units [Member] [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	58,206
Summary of Service-Based Restricted Stock Unit and Restricted Share Activity [Abstract]
Service-Based RSUs and Restricted Shares Outstanding, Weighted Average Grant Date Fair Value	$ 0.00
Service-Based RSUs and Restricted Shares Outstanding	0
Service-Based RSUs and Restricted Shares, Grants in Period, Weighted Average Grant Date Fair Value	$ 32.03
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	0
Service-Based RSUs and Restricted Shares, Vested in Period, Weighted Average Grant Date Fair Value	$ 0.00
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	0
Service-Based RSUs and Restricted Shares, Forfeitures, Weighted Average Grant Date Fair Value	$ 0.00
Service-Based RSUs and Restricted Shares Outstanding	58,206
Service-Based RSUs and Restricted Shares Outstanding, Weighted Average Grant Date Fair Value	$ 32.03
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	93,161
Summary of Service-Based Restricted Stock Unit and Restricted Share Activity [Abstract]
Service-Based RSUs and Restricted Shares Outstanding, Weighted Average Grant Date Fair Value	$ 23.57
Service-Based RSUs and Restricted Shares Outstanding	678,381
Service-Based RSUs and Restricted Shares, Grants in Period, Weighted Average Grant Date Fair Value	$ 35.12
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(109,687)
Service-Based RSUs and Restricted Shares, Vested in Period, Weighted Average Grant Date Fair Value	$ 22.60
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(34,949)
Service-Based RSUs and Restricted Shares, Forfeitures, Weighted Average Grant Date Fair Value	$ 24.33
Service-Based RSUs and Restricted Shares Outstanding	626,906
Service-Based RSUs and Restricted Shares Outstanding, Weighted Average Grant Date Fair Value	$ 25.41