Share Based Compensation (Summary Of Restricted Stock Units Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Beginning Balance	136,575	291,625
Grants	36,294
Vested		(6,750)	(27,115)
Forfeitures	(2,983)	(1,350)
Shares outstanding	146,298	136,575
Average exercised price beginning balance	$ 23.17	$ 23.23
Granted	$ 58.10
Forfeitures	$ 58.10	$ 24.33
Averaged exercised price ending balance	$ 30.97	$ 23.17
Exercised aggregate intrinsic value	$ 971	$ 7,001
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Beginning Balance	98,625	87,701
Grants	19,386	27,932
Vested		17,008
Forfeitures	38,987
Shares outstanding	79,024	98,625
Average exercised price beginning balance	$ 42.21	$ 38.98
Granted	$ 57.09	$ 55.45
Vested		$ 47.27
Forfeitures	$ 43.30
Averaged exercised price ending balance	$ 45.32	$ 42.21
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Beginning Balance	71,826	75,093
Grants	40,212	40,699
Vested	(37,381)	(40,337)
Forfeitures	(7,122)	(3,629)
Shares outstanding	67,535	71,826
Average exercised price beginning balance	$ 47.99	$ 38.61
Granted	$ 58.27	$ 55.27
Vested	$ 47.87	$ 43.91
Forfeitures	$ 51.16	$ 51.17
Averaged exercised price ending balance	$ 54.35	$ 47.99

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The total accumulated difference between fair values of underlying shares on dates of exercise and exercise price on options which were exercised (or share units converted) into shares during the reporting period under the plan.

+ References

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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.

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Net number of share options (or share units) granted during the period.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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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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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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