FAIR VALUE (Tables)

12 Months Ended

Sep. 30, 2012

Fair Value Disclosures [Abstract]

Fair Value, by Balance Sheet Grouping [Text Block]

The estimated fair value of long-term debt at NJNG and NJR, including current maturities and excluding capital leases, as applicable, is as follows:

	September 30,
(Thousands)	2012		2011
NJNG
Carrying value	$	329,845	$	329,845
Fair market value	$	364,394	$	357,930
NJR
Carrying value	$	150,000	$	50,000
Fair market value	$	165,662	$	58,565

Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis [Text Block]

Assets and liabilities measured at fair value on a recurring basis are summarized as follows:

	Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs			Significant Unobservable Inputs
(Thousands)	(Level 1)			(Level 2)			(Level 3)			Total
As of September 30, 2012:
Assets:
Physical forward commodity contracts		$	—		$	20,248		$	—	$	20,248
Financial derivative contracts - natural gas		14,270			15,645			—		29,915
Financial commodity contracts - foreign exchange		—			186			—		186
Available for sale equity securities - energy industry (1)		11,009			—			—		11,009
Other (2)		30			—			—		30
Total assets at fair value		$	25,309		$	36,079		$	—	$	61,388
Liabilities:
Physical forward commodity contracts		$	—		$	9,746		$	—	$	9,746
Financial commodity contracts - natural gas		16,922			18,793			—		35,715
Financial commodity contracts - foreign exchange		—			112			—		112
Other		—			—			—		—
Total liabilities at fair value		$	16,922		$	28,651		$	—	$	45,573
As of September 30, 2011:
Assets:
Physical forward commodity contracts		$	—		$	37,690		$	—	$	37,690
Financial derivative contracts - natural gas		25,617			43,266			—		68,883
Financial commodity contracts - foreign exchange		—			280			—		280
Available for sale equity securities - energy industry(1)		10,348			—			—		10,348
Other (2)		2,204			—			—		2,204
Total assets at fair value		$	38,169		$	81,236		$	—	$	119,405
Liabilities:
Physical forward commodity contracts		$	—		$	11,351		$	—	$	11,351
Financial derivative contracts - natural gas		23,715			39,959			—		63,674
Financial commodity contracts - foreign exchange		—			14			—		14
Other		—			—			—		—
Total liabilities at fair value		$	23,715		$	51,324		$	—	$	75,039

(1) Included in other noncurrent assets on the Consolidated Balance Sheets.

(2) Includes various money market funds.