Stockholders' Equity Stock-Option Activity and Related Share-Based Compensation Expense (Details) shares in Thousands	6 Months Ended
	Jan. 31, 2016 $ / shares shares
Number of Shares
Options outstanding, beginning balance | shares	8,713
Options granted, number of shares (in shares) | shares	9
Options exercised, number of shares (in shares) | shares	(999)
Options canceled or expired, number of shares (in shares) | shares	(293)
Options outstanding, ending balance | shares	7,430
Weighted Average Exercise Price Per Share
Weighted average exercise price per share, Beginning Balance (in USD per share) | $ / shares	$ 69.13
Options granted, weighted average exercise price per share (in USD per share) | $ / shares	94.88
Options exercised, weighted average exercise price per share (in USD per share) | $ / shares	46.65
Options canceled or expired, weighted average exercise price per share (in USD per share) | $ / shares	74.11
Weighted average exercise price per share, Beginning Balance (in USD per share) | $ / shares	$ 71.98
Exercisable (in shares) | shares	4,043
Exercisable, Weighted average exercise price per share (in USD per share) | $ / shares	$ 55.13