Stockholder's Investments - Summary of Activity under Company's Share-Based Compensation Plans (Detail) - USD ($)	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
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	$ 21,803
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	$ 2,797	$ 805
Options Outstanding, Beginning Balance, Price Lower Range	$ 20.95
Options Outstanding, Beginning Balance, Price Upper Range	38.31
Options Granted, Price Lower Range	19.96
Options Granted, Price Upper Range	25.35
Options Exercised, Price Lower Range	20.95
Options Exercised, Price Upper Range	31.07
Options Cancelled, Price Lower Range	19.96
Options Cancelled, Price Upper Range	38.31
Options Outstanding, Ending Balance, Price Lower Range	19.96	$ 20.95
Options Outstanding, Ending Balance, Price Upper Range	$ 38.31	$ 38.31
Options, Outstanding [Roll Forward]
Shares Outstanding, Beginning Balance	3,500,951
Options Granted	881,744
Options Exercised	(194,419)
Options Cancelled	(479,570)
Shares Outstanding, Ending Balance	3,708,706	3,500,951
Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options Outstanding, Beginning Balance, Weighted Average Exercise Price	$ 29.64
Options Granted, Weighted Average Exercise Price	20.02	$ 22.76	$ 30.98
Options Exercised, Weighted Average Exercise Price	26.98
Options Cancelled, Weighted Average Exercise Price	30.89
Options Outstanding, Ending Balance, Weighted Average Exercise Price	$ 27.33	29.64
Options Outstanding, Range of Exercise Prices [Abstract]
Exercise Price Range, Number of Outstanding Options	3,708,706
Exercise Price Range, Options Outstanding, Weighted Average Remaining Contractual Term	5 years 7 months 6 days
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 27.61
Exercise Price Range, Number of Exercisable Options	2,488,527
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	4 years
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 30.18
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted Shares and RSUs, Grants in Period, Weighted Average Grant Date Fair Value		$ 24.28
$20.95 - $26.99 [Member]
Options Outstanding, Range of Exercise Prices [Abstract]
Exercise Price Range, Number of Outstanding Options	1,433,278
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	$ 21.80
Exercise Price Range, Number of Exercisable Options	291,899
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	5 years 2 months 12 days
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 20.97
$27.00 - $32.99 [Member]
Options Outstanding, Range of Exercise Prices [Abstract]
Exercise Price Range, Number of Outstanding Options	1,696,428
Exercise Price Range, Options Outstanding, Weighted Average Remaining Contractual Term	4 years 10 months 24 days
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 29.05
Exercise Price Range, Number of Exercisable Options	1,617,628
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	4 years 8 months 12 days
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 29.12
$33.00 - $38.31 [Member]
Options Outstanding, Range of Exercise Prices [Abstract]
Exercise Price Range, Number of Outstanding Options	579,000
Exercise Price Range, Options Outstanding, Weighted Average Remaining Contractual Term	1 year 3 months 18 days
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 37.78
Exercise Price Range, Number of Exercisable Options	579,000
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	1 year 3 months 18 days
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 37.78
Service Based Restricted Shares and Restricted Stock Units [Member]
Restricted Shares and RSUs, Nonvested, Number of Shares [Roll Forward]
Restricted Shares and RSUs, Nonvested, Number	677,454
Restricted Shares and RSUs, Grants in Period	173,394
Restricted Shares and RSUs, Vested in Period	(113,640)
Restricted Shares and RSUs, Forfeited in Period	(58,827)
Restricted Shares and RSUs, Nonvested, Number	678,381	677,454
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value	$ 24.72
Restricted Shares and RSUs, Grants in Period, Weighted Average Grant Date Fair Value	20.07
Restricted Shares and RSUs, Vested in Period, Weighted Average Grant Date Fair Value	24.97
Restricted Shares and RSUs, Forfeitures, Weighted Average Grant Date Fair Value	23.81
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value	$ 23.57	$ 24.72