Stock-Based Compensation - Summary of Activity under Company's Share-Based Compensation Plans (Detail) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Apr. 30, 2018	Apr. 30, 2017
Summary of Stock Option Activity [Abstract]
Options Outstanding at July 31, 2014	2,879,801
Options Outstanding at July 31, 2014, Weighted Average Exercise Price	$ 27.40
Options, Grants in Period	364,046
Options, Grants in Period, Weighted Average Exercise Price	$ 36.85	$ 35.14
Options, Exercised in Period	(400,282)
Options, Exercised in Period, Weighted Average Exercise Price	$ 30.95
Options, Forfeitures and Expirations in Period	(106,715)
Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 31.46
Options Outstanding at January 31, 2015	2,736,850
Options Outstanding at January 31, 2015, Weighted Average Exercise Price	$ 27.98
Options Outstanding, Exercisable, Weighted Average Exercise Price	$ 26.63	28.37
Options Outstanding, Weighted Average Remaining Contractual Term	6 years
Options Outstanding, Aggregate Intrinsic Value	$ 24,032
Options Outstanding, Exercisable, Weighted Average Remaining Contractual Term	5 years
Options Outstanding, Exercisable, Aggregate Intrinsic Value	$ 19,750
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	$ 35.13
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	56,290
Summary of Service-Based Restricted Stock Unit and Restricted Share Activity [Abstract]
Service-Based RSUs and Restricted Shares Outstanding	58,206
Service-Based RSUs and Restricted Shares, Grants in Period, Weighted Average Grant Date Fair Value	$ 33.12	$ 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	(6,399)
Service-Based RSUs and Restricted Shares, Forfeitures, Weighted Average Grant Date Fair Value	$ 32.57
Service-Based RSUs and Restricted Shares Outstanding	108,097
Service-Based RSUs and Restricted Shares Outstanding, Weighted Average Grant Date Fair Value	$ 32.57
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	93,118
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	$ 25.61
Service-Based RSUs and Restricted Shares Outstanding	517,108
Service-Based RSUs and Restricted Shares, Grants in Period, Weighted Average Grant Date Fair Value	$ 36.79
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(137,302)
Service-Based RSUs and Restricted Shares, Vested in Period, Weighted Average Grant Date Fair Value	$ 24.73
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(42,556)
Service-Based RSUs and Restricted Shares, Forfeitures, Weighted Average Grant Date Fair Value	$ 27.10
Service-Based RSUs and Restricted Shares Outstanding	430,368
Service-Based RSUs and Restricted Shares Outstanding, Weighted Average Grant Date Fair Value	$ 28.16