Stock-Based Compensation - Summary of Stock Option Activity under Company's Share-Based Compensation Plans (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended				3 Months Ended		3 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014 Service Based Option [Member]	Jul. 31, 2014 Service Based Option [Member]	Oct. 31, 2014 Service Based Restricted Shares and Restricted Stock Units [Member]	Jul. 31, 2014 Service Based Restricted Shares and Restricted Stock Units [Member]	Oct. 31, 2014 Performance Based Restricted Shares and Restricted Stock Units [Member]	Jul. 31, 2014 Performance Based Restricted Shares and Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding, ending balance, weighted average remaining contractual term	5 years 5 months
Options outstanding, exercisable, weighted average remaining contractual term	4 years 2 months
Options outstanding, ending balance, aggregate intrinsic value	$ 1,175,785
Options outstanding, exercisable, aggregate intrinsic value	$ 584,528
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options Outstanding			4,343,342	4,204,260
Options Outstanding, Weighted Average Exercise Price			$ 29.79	$ 30.82
Options, Grants in Period	612,427
Options, Grants in Period, Weighted Average Exercise Price	$ 22.66	$ 31.07
Options, Exercised in Period			(3,500)
Options, Exercises in Period, Weighted Average Exercise Price			$ 20.95
Options, Forfeitures or Expirations in Period			(469,845)
Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price			$ 29.81
Options Exercisable	3,339,992	3,466,777
Weighted average exercise price of options exercisable	$ 30.94	$ 30.93
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Equity Instruments Other than Options, Nonvested, Number					277,320	104,857	0	80,000
Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value					$ 24.90	$ 31.02	$ 0.00	$ 32.50
RSUs and Restricted Shares, Grants in Period					224,398		0
RSUs and Restricted Shares, Grants in Period, Weighted Average Grant Date Fair Value					$ 23.45		$ 0.00
Equity Instruments Other than Options, Vested in Period					32,458		0
Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value					$ 30.86		$ 0.00
Equity Instruments Other than Options, Forfeited in Period					(19,477)		(80,000)
Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value					$ 31.28		$ 32.50