Stockholders' Equity Restricted Stock Unit Activity and Related Share-Based Compensation Expense (Details) shares in Thousands	6 Months Ended
	Jan. 31, 2016 $ / shares shares
Number of Shares
Nonvested at beginning of period (in shares) | shares	8,916
Granted, Number of shares (in shares) | shares	296
Vested, Number of Shares (in shares) | shares	(796)
Forfeited, Number of Shares (in shares) | shares	(1,032)
Nonvested at end of period (in shares) | shares	7,384
Weighted Average Grant Date Fair Value
Nonvested, Weighted Average Grant Date Fair Value, at beginning of period (in USD per shares) | $ / shares	$ 76.64
Granted, Weighted Average Grant Date Fair Value (in USD per shares) | $ / shares	96.50
Vested, Weighted Average Grant Date Fair Value (in USD per shares) | $ / shares	68.44
Forfeited, Weighted Average Grant Date Fair Value (in USD per shares) | $ / shares	69.71
Nonvested, Weighted Average Grant Date Fair Value, at end of period (in USD per shares) | $ / shares	$ 79.29