Stockholder's Investments - Summary of Stock Option Activity under Company's Share-Based Compensation Plans (Detail) (USD $)	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Price Lower Range	$ 17.23	$ 17.23	$ 13.31	$ 13.31
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Price Upper Range	$ 40.37	$ 40.37	$ 40.37	$ 40.37
Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Price Lower Range	$ 29.28	$ 30.21	$ 27.00
Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Price Upper Range	$ 31.07	$ 36.25	$ 33.54
Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Price Lower Range	$ 17.33	$ 13.31	$ 13.31
Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Price Upper Range	$ 30.21	$ 31.54	$ 29.78
Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period Price Lower Range	$ 20.95	$ 16.39	$ 16.00
Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period Price Upper Range	$ 38.31	$ 38.31	$ 38.31
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares outstanding, beginning balance	5,106,585	6,253,751	5,726,017
Shares outstanding, exercised	(490,507)	(1,080,089)	(266,991)
Shares outstanding, forfeited or expired	(787,090)	(895,527)	(417,725)
Shares outstanding, ending balance	4,204,260	5,106,585	6,253,751
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options outstanding, beginning balance, weighted average exercise price (USD per share)	$ 30.68	$ 29.24	$ 29.24
Options outstanding, exercised, weighted average exercise price (USD per share)	$ 26.45	$ 22.79	$ 20.21
Options outstanding, forfeited or expired, weighted average exercise price (USD per share)	$ 32.71	$ 30.02	$ 31.16
Options outstanding, ending balance, weighted average exercise price (USD per share)	$ 30.82	$ 30.68	$ 29.24
Options outstanding, ending balance, weighted average remaining contractual term	5 years 4 months 25 days
Options outstanding, exercisable	3,004,348
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	4 years 3 months 20 days
Weighted average exercise price of options exercisable	$ 31.15	$ 31.46	$ 29.69
Service Based Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares outstanding, new grants	375,272	828,450	1,212,450
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted average exercise price (USD per share)	$ 30.98	$ 30.58	$ 27.91
17.00 - 27.99 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares outstanding, ending balance	664,383
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options outstanding, ending balance, weighted average exercise price (USD per share)	$ 25.00
Options outstanding, ending balance, weighted average remaining contractual term	6 years 2 months 11 days
Options outstanding, exercisable	504,258
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	5 years 9 months 20 days
Weighted average exercise price of options exercisable	$ 24.32
28.00 - 37.99 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares outstanding, ending balance	2,956,377
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options outstanding, ending balance, weighted average exercise price (USD per share)	$ 30.66
Options outstanding, ending balance, weighted average remaining contractual term	5 years 8 months 11 days
Options outstanding, exercisable	1,916,590
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	4 years 4 months 25 days
Weighted average exercise price of options exercisable	$ 30.77
38.00 and Up [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares outstanding, ending balance	583,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options outstanding, ending balance, weighted average exercise price (USD per share)	$ 38.26
Options outstanding, ending balance, weighted average remaining contractual term	2 years 9 months 20 days
Options outstanding, exercisable	583,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	2 years 9 months 20 days
Weighted average exercise price of options exercisable	$ 38.26
Service Based Restricted Shares and Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares outstanding, new grants	108,055	5,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 30.93	$ 32.99
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$ 0	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	8,198	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 31.05	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	104,857	5,000	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 31.02	$ 32.99	$ 0
Performance Based Restricted Shares and Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares outstanding, new grants	0	10,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 0.00	$ 30.21
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(35,001)	(33,333)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$ 0	$ 28.35
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(116,666)	(55,000)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 0	$ 32.83
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	80,000	231,667	310,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 0	$ 31.43	$ 31.38