Stockholders' Equity (Schedule Of Stock Option Activity) (Details) (USD $)	12 Months Ended
Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2009
Stockholders' Equity
Outstanding at beginning of year, Shares	1,381,725	513,561	514,561
Exercised, Shares	(78,500)	(586)	(1,000)
Canceled, Shares		(1,250)
Granted, Shares	130,000	870,000
Outstanding at end of year, Shares	1,433,225	1,381,725	513,561
Vested and expected to vest at end of year, Shares	833,225	1,381,725	513,561
Exercisable at year-end, Shares	609,891	445,057	380,227
Outstanding at beginning of year, Weighted-Average Exercise Price	$ 30.20	$ 23.47	$ 23.48
Exercised, Weighted-Average Exercise Price	$ 13.33	$ 26.91	$ 26.91
Canceled, Weighted-Average Exercise Price		$ 27.40
Granted, Weighted-Average Exercise Price	$ 27.72	$ 34.17
Outstanding at end of year, Weighted-Average Exercise Price	$ 30.90	$ 30.20	$ 23.47
Vested and expected to vest at end of year, Weighted-Average Exercise Price	$ 27.82	$ 30.20	$ 23.47
Exercisable at year-end, Weighted-Average Exercise Price	$ 27.84	$ 22.99	$ 22.39

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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The weighted average price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period.

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest.

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