Stockholder's Investments - Summary of Activity under Company's Share-Based Compensation Plans (Detail) - $ / shares	12 Months Ended
	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Beginning Balance, Price Lower Range	$ 17.23
Options Outstanding, Beginning Balance, Price Upper Range	40.37
Options Granted, Price Lower Range	22.66
Options Granted, Price Upper Range	27.28
Options Exercised, Price Lower Range	17.23
Options Exercised, Price Upper Range	27.00
Options Cancelled, Price Lower Range	22.63
Options Cancelled, Price Upper Range	40.37
Options Outstanding, Ending Balance, Price Lower Range	20.95	$ 17.23
Options Outstanding, Ending Balance, Price Upper Range	$ 38.31	$ 40.37
Options, Outstanding [Roll Forward]
Shares Outstanding, Beginning Balance	4,204,260
Options Granted	628,340
Options Exercised	(68,533)
Options Cancelled	(1,263,116)
Shares Outstanding, Ending Balance	3,500,951	4,204,260
Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options Outstanding, Beginning Balance, Weighted Average Exercise Price	$ 30.82
Options Granted, Weighted Average Exercise Price	22.76	$ 30.98	$ 30.58
Options Exercised, Weighted Average Exercise Price	23.73
Options Cancelled, Weighted Average Exercise Price	30.48
Options Outstanding, Ending Balance, Weighted Average Exercise Price	$ 29.64	$ 30.82
Options Outstanding, Range of Exercise Prices [Abstract]
Exercise Price Range, Number of Outstanding Options	3,500,951
Exercise Price Range, Options Outstanding, Weighted Average Remaining Contractual Term	5 years 3 months 18 days
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 29.64
Exercise Price Range, Number of Exercisable Options	2,642,955
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	4 years 3 months 18 days
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 30.88
$20.95 - $26.99 [Member]
Options Outstanding, Range of Exercise Prices [Abstract]
Exercise Price Range, Number of Outstanding Options	711,527
Exercise Price Range, Options Outstanding, Weighted Average Remaining Contractual Term	7 years 8 months 12 days
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 22.27
Exercise Price Range, Number of Exercisable Options	180,667
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	3 years 4 months 24 days
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 20.95
$27.00 - $32.99 [Member]
Options Outstanding, Range of Exercise Prices [Abstract]
Exercise Price Range, Number of Outstanding Options	1,976,924
Exercise Price Range, Options Outstanding, Weighted Average Remaining Contractual Term	5 years 9 months 18 days
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 29.12
Exercise Price Range, Number of Exercisable Options	1,667,452
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	5 years 6 months
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 28.86
$33.00 - $38.31 [Member]
Options Outstanding, Range of Exercise Prices [Abstract]
Exercise Price Range, Number of Outstanding Options	812,500
Exercise Price Range, Options Outstanding, Weighted Average Remaining Contractual Term	2 years
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 37.34
Exercise Price Range, Number of Exercisable Options	794,836
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	1 year 9 months 18 days
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 37.39
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	104,857
Restricted Shares and RSUs, Grants in Period	661,412
Restricted Shares and RSUs, Vested in Period	(34,247)
Restricted Shares and RSUs, Forfeited in Period	(54,568)
Restricted Shares and RSUs, Nonvested, Number	677,454	104,857
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value	$ 31.02
Restricted Shares and RSUs, Grants in Period, Weighted Average Grant Date Fair Value	24.28	$ 30.93	32.99
Restricted Shares and RSUs, Vested in Period, Weighted Average Grant Date Fair Value	30.79
Restricted Shares and RSUs, Forfeitures, Weighted Average Grant Date Fair Value	27.64
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value	$ 24.72	$ 31.02
Performance Based Restricted Shares and Restricted Stock Units [Member]
Restricted Shares and RSUs, Nonvested, Number of Shares [Roll Forward]
Restricted Shares and RSUs, Nonvested, Number	80,000
Restricted Shares and RSUs, Grants in Period	0
Restricted Shares and RSUs, Vested in Period	0
Restricted Shares and RSUs, Forfeited in Period	(80,000)
Restricted Shares and RSUs, Nonvested, Number	0	80,000
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value	$ 32.50
Restricted Shares and RSUs, Grants in Period, Weighted Average Grant Date Fair Value	0.00		$ 30.21
Restricted Shares and RSUs, Vested in Period, Weighted Average Grant Date Fair Value	0.00
Restricted Shares and RSUs, Forfeitures, Weighted Average Grant Date Fair Value	32.50
Restricted Shares and RSUs, Nonvested, Weighted Average Grant Date Fair Value	$ 0.00	$ 32.50