DERIVATIVE INSTRUMENTS (Tables)

3 Months Ended

Dec. 31, 2011

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Text Block]

The following table reflects the fair value of NJR's derivative assets and liabilities recognized in the Unaudited Condensed Consolidated Balance Sheets as of:

			Fair Value
			December 31, 2011						September 30, 2011
(Thousands)	Balance Sheet Location	Asset Derivatives			Liability Derivatives			Asset Derivatives			Liability Derivatives
Derivatives designated as hedging instruments:
NJRES:
Foreign currency contracts	Derivatives - current		$	143		$	2		$	153		$	8
	Derivatives - noncurrent		82			20			127			6
Fair value of derivatives designated as hedging instruments			$	225		$	22		$	280		$	14
Derivatives not designated as hedging instruments:
NJNG:
Financial commodity contracts	Derivatives - current		$	2,669		$	29,051		$	5,424		$	13,258
	Derivatives - noncurrent		—			—			2			620
NJRES:
Physical forward commodity contracts	Derivatives - current		20,535			11,833			33,240			10,570
	Derivatives - noncurrent		3,333			2,818			4,450			781
Financial commodity contracts	Derivatives - current		96,279			38,427			61,521			44,862
	Derivatives - noncurrent		3,949			4,658			1,936			4,934
Fair value of derivatives not designated as hedging instruments			$	126,765		$	86,787		$	106,573		$	75,025
Total fair value of derivatives			$	126,990		$	86,809		$	106,853		$	75,039

Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block]

The following table reflects the effect of derivative instruments on the Unaudited Condensed Consolidated Statements of Operations as of:

(Thousands)	Location of gain (loss) recognized in income on derivatives	Amount of gain (loss) recognized in income on derivatives
		Three Months Ended
		December 31,
Derivatives not designated as hedging instruments:		2011			2010
NJRES:
Physical commodity contracts	Operating revenues	$	(11,908	)	$	(16,469	)
Physical commodity contracts	Gas purchases	4,275			3,709
Financial commodity contracts	Gas purchases	62,454			(28,271		)
Total unrealized and realized gains (losses)		$	54,821		$	(41,031	)

Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Text Block]

The following table reflect the effect of derivative instruments designated as cash flow hedges on OCI as of:

(Thousands)	Amount of Gain or (Loss) Recognized in OCI on Derivatives (Effective Portion) (1)						Amount of Gain or (Loss) Reclassified from OCI into Income (Effective Portion)				Amount of Gain or (Loss) Recognized on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing)
	Three Months Ended						Three Months Ended				Three Months Ended
	December 31,						December 31,				December 31,
Derivatives in cash flow hedging relationships:	2011			2010			2011		2010		2011		2010
Foreign currency contracts	$	(76	)	$	(144	)	$	13	$	5	$	—	$	—

(1) The settlement of foreign currency transactions over the next twelve months is expected to result in the reclassification of $141,000 from OCI into earnings. The maximum tenor is April 2015.

Schedule of Derivative Instruments [Text Block]

NJNG and NJRES had the following outstanding long (short) derivatives as of:

		Volume (Bcf)
		December 31, 2011		September 30, 2011
NJNG	Futures	21.9		23.7
	Swaps	(3.6	)	(1.8	)
	Options	1.0		1.1
NJRES	Futures	(23.3	)	(13.8	)
	Swaps	(10.2	)	(41.9	)
	Options	—		—
	Physical	28.4		58.3

Schedule of Due to (from) Broker-Dealers and Clearing Organizations [Text Block]

The Company maintains broker margin accounts for NJNG and NJRES. The balances by company, are as follows:

(Thousands)	Balance Sheet Location	December 31, 2011			September 30, 2011
NJNG	Broker margin - Current assets	$	30,774		$	11,722
NJRES	Broker margin - Current assets	$	20,155		$	10,873
NJRES	Broker margin - Current (liabilities)	$	(31,802	)	$	—

Schedules of Concentration of Risk, by Risk Factor [Table Text Block]

The amounts presented below have not been reduced by any collateral received or netting and exclude accounts receivable for NJNG retail natural gas sales and services.

(Thousands)	Gross Credit Exposure
Investment grade		$	188,510
Noninvestment grade		23,824
Internally rated investment grade		40,072
Internally rated noninvestment grade		5,100
Total		$	257,506