Stock Repurchases (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2018	Oct. 31, 2016	Jan. 31, 2018
Share-Based Compensation Arrangement By Share-Based Payment Award, Options Exercisable [Abstract]
Options Exercised			1,194,000
Weighted Average Exercise Price			$ 14.35
Common Stock
Share-Based Compensation Arrangement By Share-Based Payment Award, Options Exercisable [Abstract]
Options Exercised	80,000	18,000,000
Weighted Average Exercise Price	$ 6.54	$ 7.70
Shares Net Settled for Exercise	11,996	5,408,972
Shares Withheld for Taxes(1)	0	5,255,322
Net Shares to Employees	68,004	7,335,706
Weighted Average Share Price for Withholding	$ 43.60	$ 25.62
Employee Stock Based Tax Withholding (in 000s)	$ 0	$ 134,615