DERIVATIVE INSTRUMENTS - BALANCE SHEET RELATED DISCLOSURES (Details) (USD $)	Dec. 31, 2013	Sep. 30, 2013
Derivatives, Fair Value [Line Items]
Derivative assets, current	$ 34,843,000	$ 53,327,000
Derivative liabilities, current	77,852,000	40,390,000
Derivative assets, noncurrent	1,931,000	2,761,000
Derivative liabilities, noncurrent	6,130,000	2,458,000
Derivative assets	36,774,000	56,088,000
Derivative liabilities	83,982,000	42,848,000
Notional amount of foreign currency derivatives	8,300,000
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	36,772,000	56,072,000
Derivative liabilities	83,937,000	42,843,000
Foreign Currency Contract [Member] \| NJRES [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative assets, current	2,000	16,000
Derivative liabilities, current	33,000	3,000
Derivative assets, noncurrent	0	0
Derivative liabilities, noncurrent	12,000	2,000
Derivative assets	2,000	16,000
Derivative liabilities	45,000	5,000
Financial Commodity Contracts [Member] \| NJRES [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative assets, current	20,015,000	38,527,000
Derivative liabilities, current	49,511,000	23,769,000
Derivative assets, noncurrent	1,115,000	2,099,000
Derivative liabilities, noncurrent	4,971,000	2,294,000
Financial Commodity Contracts [Member] \| NJNG [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative assets, current	6,586,000	3,502,000
Derivative liabilities, current	39,000	2,045,000
Derivative assets, noncurrent	0	121,000
Derivative liabilities, noncurrent	0	140,000
Physical Forward Commodity Contracts [Member] \| NJRES [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative assets, current	8,240,000	11,282,000
Derivative liabilities, current	28,269,000	14,573,000
Derivative assets, noncurrent	816,000	541,000
Derivative liabilities, noncurrent	$ 1,147,000	$ 22,000

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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- Definition

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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