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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - GAS IN STORAGE (Details) $ in Thousands | Sep. 30, 2017 USD ($) Bcf | Sep. 30, 2016 USD ($) Bcf
--- | --- | ---
Public Utilities, Inventory [Line Items] |  |
Gas in Storage | $ | $ 202,063 | $ 206,251
Bcf | Bcf | 75.7 | 83.3
Energy Services |  |
Public Utilities, Inventory [Line Items] |  |
Gas in Storage | $ | $ 122,884 | $ 130,493
Bcf | Bcf | 53.9 | 62.0
Natural Gas Distribution |  |
Public Utilities, Inventory [Line Items] |  |
Gas in Storage | $ | $ 79,179 | $ 75,758
Bcf | Bcf | 21.8 | 21.3

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- Definition Natural Gas in Storage Nonmonetary Number of Billion Cubic Feet of Gas in Storage as of the balance sheet date. + References No definition available. + Details
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- Definition Carrying amount as of the balance sheet date of natural gas in storage, which is a mixture of gases (liquefied or otherwise), used for fuel and manufacturing purposes, which is ready for sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.6(a)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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