DEBT - SCHEDULE OF LONG TERM DEBT (Details) (USD $)	0 Months Ended	6 Months Ended	12 Months Ended
	Apr. 15, 2013	Mar. 31, 2013 NJNG [Member]	Sep. 30, 2012 NJNG [Member]	Mar. 31, 2013 NJNG [Member] Bank Credit Facilities Short term [Member]		Sep. 30, 2012 NJNG [Member] Bank Credit Facilities Short term [Member]
Debt Instrument [Line Items]
Sale leaseback transaction, gross proceeds		$ 7,100,000	$ 6,500,000
Line of credit facility, maximum borrowing capacity				250,000,000	[1]	200,000,000	[1]
Proceeds from Issuance of Long-term Debt	$ 50,000,000
Debt Instrument, Interest Rate, Stated Percentage	3.15%

[1] Committed credit facilities, which require commitment fees on the unused amounts.