Summary Of Significant Accounting Policies Summary Of Significant Accounting Policies (Reclassification Out of Accumulated Other Comprehensive Loss) (Details) (USD $)
In Thousands, unless otherwise specified |
3 Months Ended | 12 Months Ended | ||||||||||||||||||
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Sep. 30, 2014
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Jun. 30, 2014
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Mar. 31, 2014
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Dec. 31, 2013
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Sep. 30, 2013
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Jun. 30, 2013
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Mar. 31, 2013
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Dec. 31, 2012
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Sep. 30, 2014
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Sep. 30, 2013
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Sep. 30, 2012
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Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | ||||||||||||||||||||
Operating Revenues | $ 366,623 | $ 440,144 | $ 756,242 | $ 550,072 | $ 338,863 | $ 440,008 | $ 597,826 | $ 452,854 | $ 2,113,081 | $ 1,829,551 | $ 1,626,853 | |||||||||
Purchased Gas | (605,838) | (460,432) | (415,589) | |||||||||||||||||
Other Income | 9,461 | 4,697 | 5,133 | |||||||||||||||||
Income Before Income Taxes | 489,027 | 432,759 | 370,631 | |||||||||||||||||
Income Tax Expense | (189,614) | (172,758) | (150,554) | |||||||||||||||||
Net Income Available for Common Stock | 57,431 | 64,520 | 95,210 | [1] | 82,252 | 47,842 | [2] | 58,495 | 85,720 | 67,944 | 299,413 | 260,001 | 220,077 | |||||||
Amount Of Gain Or (Loss) Reclassified From Accumulated Other Comprehensive Loss [Member]
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Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | ||||||||||||||||||||
Income Before Income Taxes | (26,188) | |||||||||||||||||||
Income Tax Expense | 12,643 | |||||||||||||||||||
Net Income Available for Common Stock | (13,545) | |||||||||||||||||||
Amount Of Gain Or (Loss) Reclassified From Accumulated Other Comprehensive Loss [Member] | Gains and Losses on Securities Available for Sale [Member]
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Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | ||||||||||||||||||||
Other Income | 662 | |||||||||||||||||||
Amount Of Gain Or (Loss) Reclassified From Accumulated Other Comprehensive Loss [Member] | Amortization of Prior Year Funded Status of Pension and Other Post-Retirement Benefit Plans [Member] | Prior Service Credit [Member]
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Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | ||||||||||||||||||||
Net periodic benefit cost | 131 | [3] | ||||||||||||||||||
Amount Of Gain Or (Loss) Reclassified From Accumulated Other Comprehensive Loss [Member] | Amortization of Prior Year Funded Status of Pension and Other Post-Retirement Benefit Plans [Member] | Net Actuarial Loss [Member]
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Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | ||||||||||||||||||||
Net periodic benefit cost | (9,334) | [3] | ||||||||||||||||||
Amount Of Gain Or (Loss) Reclassified From Accumulated Other Comprehensive Loss [Member] | Commodity Contract [Member] | Gains and Losses on Derivative Financial Instruments [Member]
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Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | ||||||||||||||||||||
Operating Revenues | (14,880) | |||||||||||||||||||
Purchased Gas | $ (2,767) | |||||||||||||||||||
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