RELATED PARTY TRANSACTIONS (Details) (USD $)	12 Months Ended								12 Months Ended							12 Months Ended	3 Months Ended
	Sep. 30, 2014	Sep. 30, 2014 NJRES to Steckman Ridge and Iroquios Affiliates [Member]	Sep. 30, 2013 NJRES to Steckman Ridge and Iroquios Affiliates [Member]	Sep. 30, 2012 NJRES to Steckman Ridge and Iroquios Affiliates [Member]	Sep. 30, 2014 NJRES to Steckman Ridge Affiliate [Member]	Sep. 30, 2013 NJRES to Steckman Ridge Affiliate [Member]	Sep. 30, 2014 NJRES to Iroquois Affiliate [Member]	Sep. 30, 2013 NJRES to Iroquois Affiliate [Member]	Sep. 30, 2014 NJNG to Steckman RIdge and Iroquios Afffiliates [Member]	Sep. 30, 2013 NJNG to Steckman RIdge and Iroquios Afffiliates [Member]	Sep. 30, 2012 NJNG to Steckman RIdge and Iroquios Afffiliates [Member]	Sep. 30, 2014 NJNG to Steckman RIdge Affiliate [Member]	Sep. 30, 2013 NJNG to Steckman RIdge Affiliate [Member]	Sep. 30, 2014 NJNG to Iroquois Affiliate [Member]	Sep. 30, 2013 NJNG to Iroquois Affiliate [Member]	Sep. 30, 2014 NJNG to NJRES Affilate [Member] MMcf	Sep. 30, 2014 NJNG to PennEast Affiliate [Member] MMcf
Related Party Transaction [Line Items]
Demand fees recognized pertaining to related party agreement		$ 6,200,000	$ 6,100,000	$ 6,600,000					$ 6,400,000	$ 5,900,000	$ 5,600,000
Due to related parties					187,000	159,000	389,000	390,000				775,000	775,000	48,000	61,000
Asset management agreement, period																10 years
Natural gas sold at cost under asset management agreement (MMcf)																3,000
Approximate annual demand fees under agreement from April 1 2010 to March 31 2020	$ 9,300,000
Transportation capacity under precedent agreement from NJNG with PennEast (MMcf)																	180