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DERIVATIVE INSTRUMENTS, VOLUME (Details) certificate in Thousands, $ in Millions	Sep. 30, 2016 USD ($) Bcf certificate	Sep. 30, 2015 Bcf	Jun. 01, 2015 USD ($)
Derivative [Line Items]
Derivative, Notional Amount | $			$ 125.0
Foreign currency contracts
Derivative [Line Items]
Derivative, Notional Amount | $	$ 3.6
NJRES | Physical commodity contracts
Derivative [Line Items]
Number of Solar Renewable Energy Certificates (in certificates) | certificate	148
Long | NJNG | Futures
Derivative [Line Items]
Outstanding long (short) derivatives (in Bcf)	23.6	25.8
Long | NJNG | Physical
Derivative [Line Items]
Outstanding long (short) derivatives (in Bcf)	9.2	0.0
Long | NJRES | Physical
Derivative [Line Items]
Outstanding long (short) derivatives (in Bcf)	94.6	48.2
Long | NJRES | Financial Options
Derivative [Line Items]
Outstanding long (short) derivatives (in Bcf)	1.2	1.2
Short | NJRES | Futures
Derivative [Line Items]
Outstanding long (short) derivatives (in Bcf)	79.1	91.1

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- 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

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- Definition

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