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DERIVATIVE INSTRUMENTS - VOLUME (Details) certificate in Thousands	Dec. 31, 2016 USD ($) Bcf certificate	Sep. 30, 2016 Bcf	Jun. 01, 2015 USD ($)
Derivative [Line Items]
Derivative, notional amount | $			$ 125,000,000
Foreign currency contracts
Derivative [Line Items]
Derivative, notional amount | $	$ 3,700,000
NJNG | Long | Futures
Derivative [Line Items]
Volume	24.3	23.6
NJNG | Long | Physical
Derivative [Line Items]
Volume	4.4	9.2
NJRES | Physical commodity contracts
Derivative [Line Items]
Number of SRECs | certificate	179
NJRES | Long | Physical
Derivative [Line Items]
Volume	70.4	94.6
NJRES | Long | Options
Derivative [Line Items]
Volume	0.5	1.2
NJRES | Short | Futures
Derivative [Line Items]
Volume	76.4	79.1

X

- Definition

Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
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- Definition

Number of Solar Renewable Energy Certificates

+ References

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- Definition

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