Income Taxes (Provision For Income Taxes Computed By Applying The Statutory Federal Income Tax Rate) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2010
Income Taxes [Abstract]
Amount computed by applying a tax rate of 35%	$ 20,287	$ 9,933	$ 10,562
State income taxes (net of federal income tax benefit)	1,900	1,441	1,370
Employment related and other tax credits, net	(1,291)	(1,730)	(1,504)
Adjustment of prior year deferred tax items	1,559
Benefit from stock option exchange program			(1,471)
Other	(578)	(490)	12
Provision for income taxes	$ 21,877	$ 9,154	$ 8,969
Statutory federal income tax rate	35.00%

The domestic federal statutory tax rate applicable under enacted tax laws to the Company's pretax income from continuing operations for the period. The "statutory" tax rate is the regular tax rate if there are alternative tax systems.

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The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to differences in the deductibility of incentive stock options and other equity-based compensation costs in accordance with generally accepted accounting principles and enacted tax laws.

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The portion of the difference, between total income tax expense or benefit as reported in the Income Statement for the year/accounting period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations, that is attributable to all other items not otherwise listed in the existing taxonomy.

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement for the current period and the expected income tax expense or benefit computed attributable to revisions of previously reported income tax expense.

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The portion of the difference, between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations, that is attributable to state and local income tax expense or benefit.

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to other tax credits generated or utilized under enacted tax laws during the period.

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