Income Taxes (Schedule Of Income Tax Reconciliation By Applying Federal Income Tax Rate) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Income Taxes [Abstract]
U.S. Income Before Income Taxes	$ 422,086	$ 366,960	$ 151,131
Income Tax Expense, Computed at U.S. Federal Statutory Rate of 35%	147,730	128,436	52,896
Increase (Reduction) in Taxes Resulting from State Income Taxes	22,969	18,951	8,294
Increase (Reduction) in Taxes Resulting From Miscellaneous	(7,015)	(6,340)	(10,767)
Total Income Taxes	$ 163,684	$ 141,047	$ 50,423
Federal Statutory Rate	35.00%

Sum of operating profit and nonoperating income (expense) from continuing and discontinued operations before income taxes and deferred investment tax credit.

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- Definition

Income Tax Disclosure [Abstract]

+ Details

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- Definition

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 shall be the regular tax rate if there are alternative tax systems.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 47

+ Details

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph h

-Article 4

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 48

-Paragraph 15, 16, 19

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 45, 46

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- Definition

The portion of the difference between total income tax expense (benefit) as reported in the Income Statement for the period and the expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to other deductions received under enacted tax laws not otherwise listed in the existing taxonomy.

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 47

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph h

-Subparagraph 2

-Article 4

+ Details

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- Definition

The portion of the difference, between total income tax expense (benefit) as reported in the Income Statement for the period and the expected income tax expense (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 (benefit).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph h

-Subparagraph 1

-Article 4

+ Details

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