Stockholders' Equity Stock-Option Activity and Related Share-Based Compensation Expense (Details) shares in Thousands	6 Months Ended
	Jan. 31, 2017 $ / shares shares
Number of Shares
Options outstanding, beginning balance (in shares) | shares	8,346
Options granted, number of shares (in shares) | shares	16
Options exercised, number of shares (in shares) | shares	(728)
Options canceled or expired, number of shares (in shares) | shares	(159)
Options outstanding, ending balance (in shares) | shares	7,475
Weighted Average Exercise Price Per Share
Weighted average exercise price per share, Beginning Balance (in USD per share) | $ / shares	$ 88.55
Options granted, weighted average exercise price per share (in USD per share) | $ / shares	116.47
Options exercised, weighted average exercise price per share (in USD per share) | $ / shares	67.81
Options canceled or expired, weighted average exercise price per share (in USD per share) | $ / shares	96.36
Weighted average exercise price per share, Ending Balance (in USD per share) | $ / shares	$ 90.46
Exercisable (in shares) | shares	3,673
Exercisable, Weighted average exercise price per share (in USD per share) | $ / shares	$ 72.52