Stock Option Plans (Narrative) (Details) (USD $)	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance	3 years
Performance award expense	$ (976,000)	$ (1,296,000)	$ (10,000)
Pre-tax stock-based compensation expense associated with stock options	9,900,000	8,300,000	7,800,000
Tax benefit associated with stock options	3,200,000	2,700,000	2,500,000
Weighted average fair value for options granted, per share	$ 11.44	$ 8.18	$ 9.37
Total intrinsic value of options exercised	21,500,000	33,700,000	29,500,000
Shares reserved	12,599,147
Aggregate intrinsic value of options outstanding	89,000,000
Aggregate intrinsic value of options exercisable	84,900,000
Total fair value of shares vested	35,500,000	29,800,000	19,500,000
Unrecognized compensation expense related to non-vested stock options granted	7,700,000
2010 Master Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance award expense	$ 700,000	$ 100,000	$ 1,900,000
After Fiscal 2003 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, years	3 years
After Fiscal 2010 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, years	3 years
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of years of service when options with a reload provision were no longer issued to officers beginning in Fiscal 2006	5 years
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of years of service that options were still issued with a reload provision to officers until Fiscal 2011	5 years
Maximum [Member] | 2010 Master Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable from date of the grant, in years	10 years