RELATED PARTY TRANSACTIONS (Details) (USD $)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
NJRES to Steckman Ridge and Iroquios Affiliates [Member]
Related Party Transaction [Line Items]
Demand fees recognized pertaining to related party agreement	$ 6,100,000	$ 6,600,000
NJRES to Steckman Ridge Affiliate
Related Party Transaction [Line Items]
Due to related parties	159,000	170,000
NJRES to Iroquois Affiliate [Member]
Related Party Transaction [Line Items]
Due to related parties	390,000	394,000
NJNG to Steckman RIdge Affiliate
Related Party Transaction [Line Items]
Due to related parties	775,000	775,000
Agreement for natural gas storage capacity between NJNG and affiliate (MMcf)	3,000
Approximate annual demand fees under agreement from April 1 2010 to March 31 2020	9,300,000
NJNG to Steckman RIdge and Iroquios Afffiliates [Member]
Related Party Transaction [Line Items]
Demand fees recognized pertaining to related party agreement	5,900,000	5,600,000
NJNG to Iroquois Affiliate [Member]
Related Party Transaction [Line Items]
Due to related parties	$ 61,000	$ 61,116
NJNG to NJRES Affilate [Member]
Related Party Transaction [Line Items]
Natural gas sold at cost under asset management agreement (MMcf)	1,000