REGULATION - REGULATORY ASSETS AND LIABILITIES (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Regulatory Assets And Liabilities [Line Items]
Regulatory assets-current	$ 27,889	$ 34,372
Regulatory assets-noncurrent	391,009	402,202
Regulatory liability-current	12,567	1,456
Regulatory liabilities-noncurrent	77,390	79,647
Overrecovered Gas Costs [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory liability-current	6,016	0
Derivatives at Fair Value, Net [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory liability-current	6,551	1,456
Cost of Removal Obligation [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory liabilities-noncurrent	76,772	79,315
Other [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory liabilities-noncurrent	618	332
Conservation Incentive Program [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory assets-current	15,080	18,887
Underrecovered Gas Costs [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory assets-current	0	953
New Jersey Clean Energy Program [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory assets-current	12,809	14,532
Environmental Remediation Costs Expended, Net of Recoveries [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory assets-noncurrent	41,762	46,968
Environmental Remediation Costs Liability for Future Expenditures [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory assets-noncurrent	183,600	183,600
Deferred Income Taxes [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory assets-noncurrent	10,718	10,718
Derivatives at Fair Value, Net [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory assets-noncurrent	0	19
SAVEGREEN [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory assets-noncurrent	29,673	30,004
Postemployment and Other Benefit Costs [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory assets-noncurrent	99,722	101,415
Deferred Superstorm Sandy Costs [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory assets-noncurrent	14,870	14,822
Other [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory assets-noncurrent	$ 10,664	$ 14,656

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Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are expected to be recovered through revenue sources within one year or the normal operating cycle, if longer. Such costs are capitalized if they meet both of the following criteria: a. It is probable that future revenue in an amount at least equal to the capitalized cost will result from inclusion of that cost in allowable costs for rate-making purposes. b. Based on available evidence, the future revenue will be provided to permit recovery of the previously incurred cost rather than to provide for expected levels of similar future costs. If the revenue will be provided through an automatic rate-adjustment clause, this criterion requires that the regulator's intent clearly be to permit recovery of the previously incurred cost.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 340

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382

+ Details

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- Definition

Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer.

+ References

+ Details

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- Definition

The amount for the individual regulatory current liability as itemized in a table of regulatory current liabilities as of the end of the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 405

-Section 25

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6500807&loc=d3e48068-110394

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- Definition

The amount for the individual regulatory noncurrent liability as itemized in a table of regulatory noncurrent liabilities as of the end of the period.

+ 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 210.5-02.24)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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