Stockholder's Investments - Summary of Activity under Company's Share-Based Compensation Plans (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Beginning Balance, Price Lower Range	$ 19.96
Options Outstanding, Beginning Balance, Price Upper Range	38.83
Options Granted, Price Lower Range	41.70
Options Granted, Price Upper Range	43.98
Options Exercised, Price Lower Range	19.96
Options Exercised, Price Upper Range	36.85
Options Cancelled, Price Lower Range	20.95
Options Cancelled, Price Upper Range	43.98
Options Outstanding, Ending Balance, Price Lower Range	19.96	$ 19.96
Options Outstanding, Ending Balance, Price Upper Range	$ 43.98	$ 38.83
Options, Outstanding [Roll Forward]
Shares Outstanding, Beginning Balance	2,504,633
Options Granted	276,238
Options Exercised	(1,154,343)
Options Cancelled	(31,812)
Shares Outstanding, Ending Balance	1,594,716	2,504,633
Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options Outstanding, Beginning Balance, Weighted Average Exercise Price	$ 28.23
Options Granted, Weighted Average Exercise Price	43.96	$ 36.85	$ 35.14
Options Exercised, Weighted Average Exercise Price	27.03
Options Cancelled, Weighted Average Exercise Price	37.95
Options Outstanding, Ending Balance, Weighted Average Exercise Price	$ 31.63	$ 28.23
Options Outstanding, Range of Exercise Prices [Abstract]
Exercise Price Range, Number of Outstanding Options	1,594,716
Exercise Price Range, Options Outstanding, Weighted Average Remaining Contractual Term	6 years 6 months
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 31.63
Exercise Price Range, Number of Exercisable Options	1,025,811
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	5 years 4 months 24 days
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 27.06
$19.96 - $26.99 [Member]
Options Outstanding, Range of Exercise Prices [Abstract]
Exercise Price Range, Number of Outstanding Options	476,603
Exercise Price Range, Options Outstanding, Weighted Average Remaining Contractual Term	5 years 10 months 24 days
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 20.64
Exercise Price Range, Number of Exercisable Options	476,603
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	5 years 10 months 24 days
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 20.64
$27.00 - $32.99 [Member]
Options Outstanding, Range of Exercise Prices [Abstract]
Exercise Price Range, Number of Outstanding Options	285,513
Exercise Price Range, Options Outstanding, Weighted Average Remaining Contractual Term	2 years 9 months 18 days
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 29.71
Exercise Price Range, Number of Exercisable Options	285,150
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	2 years 9 months 18 days
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 29.71
$33.00 - $43.98 [Member]
Options Outstanding, Range of Exercise Prices [Abstract]
Exercise Price Range, Number of Outstanding Options	832,600
Exercise Price Range, Options Outstanding, Weighted Average Remaining Contractual Term	8 years 1 month 6 days
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 38.58
Exercise Price Range, Number of Exercisable Options	264,058
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	7 years 6 months
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 35.77
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, Vested in Period, Fair Value	$ 9,859	$ 8,237
Restricted Shares and RSUs, Nonvested, Number of Shares [Roll Forward]
Restricted Shares and RSUs, Nonvested, Number	342,856
Restricted Shares and RSUs, Grants in Period	84,231
Restricted Shares and RSUs, Vested in Period	(212,788)
Restricted Shares and RSUs, Forfeited in Period	(25,661)
Restricted Shares and RSUs, Nonvested, Number	188,638	342,856
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value	$ 29.05
Restricted Shares and RSUs, Grants in Period, Weighted Average Grant Date Fair Value	44.20	$ 36.80
Restricted Shares and RSUs, Vested in Period, Weighted Average Grant Date Fair Value	26.73
Restricted Shares and RSUs, Forfeitures, Weighted Average Grant Date Fair Value	31.07
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value	$ 38.15	$ 29.05
Performance 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, Aggregate Intrinsic Value, Nonvested	$ 17,953	$ 17,249
Restricted Shares and RSUs, Nonvested, Number of Shares [Roll Forward]
Restricted Shares and RSUs, Nonvested, Number	108,097
Restricted Shares and RSUs, Grants in Period	50,313
Restricted Shares and RSUs, Nonvested, Number	158,410	108,097
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value	$ 32.57
Restricted Shares and RSUs, Grants in Period, Weighted Average Grant Date Fair Value	50.70	$ 33.12
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value	$ 38.33	$ 32.57