Discontinued Operations (Details) (USD $) In Thousands	3 Months Ended	9 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Discontinued Operation Income Loss From Discontinued Operation Disclosures Abstract
Operating revenues	$ 11,524	$ 8,952	$ 71,047	$ 62,121
Purchased gas cost	5,460	3,390	44,993	39,836
Gross profit	6,064	5,562	26,054	22,285
Operating expenses	4,472	3,712	12,919	11,654
Operating income	1,592	1,850	13,135	10,631
Miscellaneous (expense)	94	75	159	264
Income from discontinued operations before income taxes	1,498	1,775	12,976	10,367
Income tax expense	590	700	5,122	4,094
Income (loss) from discontinued operations	908	1,075	7,854	6,273
Disposal Group Including Discontinued Operation Balance Sheet Disclosures Abstract
Net plant, property & equipment	126,375		126,375
Gas stored underground	5,938		5,938
Other current assets	431		431
Deferred charges and other assets	197		197
Assets held for sale	132,941		132,941
Accounts payable	1,808		1,808
Other current liabilities	5,086		5,086
Regulatory cost of removal	11,435		11,435
Deferred credits and other liabilities	810		810
Liabilities held for sale	$ 19,139		$ 19,139
Other Discontinued Operations Disclosures Abstract
Disposal Group Sales Price			124000000

Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity for discontinued operations.

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Amount, if any, of interest and miscellaneous expenses attirbuted to the discontinued operations during the reporting period.

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The total amount of operating revenues recognized during the period for discontinued operations.

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Cost of gas purchased during the reporting period for discontinued operations.

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For the disposal group, including a component of the entity (discontinued operation), carrying amount as of the balance sheet date of natural gas stored underground in depleted gas reservoirs, aquifers, or salt caverns to meet seasonal and peak load demands, and also as insurance against unforeseen supply disruptions, and deemed to be a current asset because it is expected to be used within twelve months or in the normal operating cycle.

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For the disposal group, including a component of the entity (discontinued operation), reflects the total obligation as of the balance sheet date to remove regulatory assets from service.

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Price at which the Company agreed to sell the disposal group, subject to purchase price adjustments at closing, if applicable.

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The aggregate value for liabilities related to a disposal group that is held for sale and anticipated to be sold in less than one year. The liabilities are expected to be discharged as part of the plan of sale for the asset.

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The aggregate value (measured at the lower of net carrying value or fair value less cost of disposal) for assets of a disposal group, including a component of the entity (discontinued operation), to be sold or that has been disposed of through sale, as of the financial statement date.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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Pretax income (loss) from operations of a business component (exclusive of any gain or loss on disposal, or provision therefore) during the reporting period, until its disposal.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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After tax income (loss) from operations of a business component (exclusive of any gain or loss on disposal, or provision therefore) during the reporting period, until its disposal.

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Income tax expense (benefit) attributable to income (loss) from discontinued operations during the phase-out period.

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For the disposal group, including a component of the entity (discontinued operation), carrying value of obligations incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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-Paragraph 47
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Amount of operating expenses attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period.

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Amount of operating income or loss attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period.

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For the disposal group, including a component of the entity (discontinued operation), carrying amount of assets not otherwise specified in the taxonomy that are expected to be realized or consumed within one year or the normal operating cycle, if longer.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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-Paragraph 47
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For the disposal group, including a component of the entity (discontinued operation), obligations not otherwise itemized that are due within one year or operating cycle, if longer, from the balance sheet date.

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For the disposal group, including a component of the entity (discontinued operation), carrying amount as of the balance sheet date of assets not otherwise specified, and which are expected to be realized or consumed after one year or beyond the normal operating cycle, if longer. For an unclassified balance sheet, represents both current and noncurrent other assets.

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For the disposal group, including a component of the entity (discontinued operation), obligations not otherwise itemized that are due after one year or operating cycle, if longer, from the balance sheet date.

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For the disposal group, including a component of the entity (discontinued operation), carrying value (net of accumulated depreciation and any write-downs) of tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year. Examples include land, buildings, vehicles and production equipment.

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-Name Statement of Financial Accounting Standard (FAS)
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-Paragraph 47
-Subparagraph a

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