DERIVATIVE INSTRUMENTS, VOLUME (Details)	Sep. 30, 2013 MMcf		Sep. 30, 2012 MMcf
NJNG [Member] | Futures [Member] | Long Position [Member]
Derivative [Line Items]
Outstanding long (short) derivatives	22,600		16,100
NJNG [Member] | Swaps [Member] | Long Position [Member]
Derivative [Line Items]
Outstanding long (short) derivatives	0	[1]	(3,400)	[1]
NJRES [Member] | Futures [Member] | Short Position [Member]
Derivative [Line Items]
Outstanding long (short) derivatives	64,200		28,600
NJRES [Member] | Swaps [Member] | Long Position [Member]
Derivative [Line Items]
Outstanding long (short) derivatives	0	[1]	(13,200)	[1]
NJRES [Member] | Options [Member] | Long Position [Member]
Derivative [Line Items]
Outstanding long (short) derivatives	1,500		4,400
NJRES [Member] | Physical [Member] | Long Position [Member]
Derivative [Line Items]
Outstanding long (short) derivatives	(7,300)
NJRES [Member] | Physical [Member] | Short Position [Member]
Derivative [Line Items]
Outstanding long (short) derivatives			(3,500)

[1] In October 2012, following the implementation of the Dodd-Frank Act, the ICE converted its cleared energy “swap” contracts to “futures” contracts and the NYMEX amended their product titles to remove the word “swap” from the titles of their “futures” and “option” contracts.