Stock Repurchases (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2017
Share-Based Compensation Arrangement By Share-Based Payment Award, Options Exercisable [Abstract]
Options Exercised			20,598,000
Weighted Average Exercise Price			$ 8.19
Common Stock
Share-Based Compensation Arrangement By Share-Based Payment Award, Options Exercisable [Abstract]
Options Exercised	18,000,000	2,260,000
Weighted Average Exercise Price	$ 7.70	$ 9.32
Shares Net Settled for Exercise	5,408,972	821,296
Shares Withheld for Taxes(1)	5,255,322	586,304
Net Shares to Employees	7,335,706	852,400
Weighted Average Share Price for Withholding	$ 25.62	$ 25.65
Tax Withholding (in 000s)	$ 134,615	$ 15,039