Income Taxes (Schedule Of Effective income Tax Rate Reconciliation) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011
Income Taxes [Abstract]
U.S statutory rate	$ 37,558	$ 22,788	$ 19,780
State and local taxes, net of federal tax benefit	1,365	1,337	889
Foreign tax rate differences	(103)	(338)	(257)
Domestic production activities deduction	(2,638)	(1,900)	(1,301)
Research and development and fuel tax credits	(289)	(105)	(239)
Other	844	49	840
Effective rate	$ 36,737	$ 21,831	$ 19,712
U.S statutory rate, percentage	35.00%	35.00%	35.00%
State and local taxes, net of federal tax benefit, percentage	1.30%	2.00%	1.60%
Foreign tax rate differences, percentage	(0.10%)	(0.50%)	(0.50%)
Domestic production activities deduction, percentage	(2.50%)	(2.90%)	(2.30%)
Research and development and fuel tax credits, percentage	(0.30%)	(0.20%)	(0.40%)
Other, percentage	0.80%	0.10%	1.50%
Effective rate, percentage	34.20%	33.50%	34.90%

A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.

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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 portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to the deduction for qualified production activities received under enacted tax laws.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by the difference between statutory income tax rates in foreign jurisdictions and the domestic federal statutory income tax rate recorded during the period.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to all other items not otherwise listed in the existing taxonomy.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by the state and local income tax expense or benefit, net of the federal tax benefit (expense) thereon, recorded during the period.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by tax credits, not otherwise listed in the existing taxonomy, generated or utilized under enacted tax laws during the period.

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The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to pretax Income or Loss from continuing operations; income tax expense or benefit may include interest and penalties on tax uncertainties based on the entity's accounting policy.

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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 the deduction for qualified production activities received under 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 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 total foreign income tax expense or benefit. The foreign income tax expense or benefit difference represents the income tax expense or benefit at applicable domestic statutory income tax rates applied to foreign earnings or loss for the period versus the foreign income tax expense or benefit calculated by applying the appropriate foreign tax rates.

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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 nondeductible research and development expenses, including in-process research and development acquired as part of a business combination, under 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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