DEBT - SCHEDULE OF LONG TERM DEBT (Details) (USD $)	24 Months Ended					24 Months Ended			3 Months Ended
	May 10, 2013 NJR [Member] Debt Shelf Facility Metlife [Member]	Mar. 31, 2013 NJR [Member] Debt Shelf Facility Metlife [Member]	Dec. 31, 2013 NJR [Member] Debt Shelf Facility Metlife [Member] Unsecured senior note 1.94% [Member]	Dec. 31, 2013 NJR [Member] Debt Shelf Facility Metlife [Member] Unsecured senior note 2.51% [Member]	Dec. 31, 2013 NJR [Member] Debt Shelf Facility JP Morgan [Member]	Jun. 30, 2013 NJR [Member] Debt Shelf Facility Prudential [Member]	Dec. 31, 2013 NJR [Member] Debt Shelf Facility Prudential [Member]	Dec. 31, 2013 NJR [Member] Debt Shelf Facility Prudential [Member] Unsecured senior note 3.25% [Member]	Dec. 31, 2013 NJNG [Member]	Dec. 31, 2012 NJNG [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 100,000,000			$ 100,000,000		$ 75,000,000
Line of credit facility, issuance period	2 years					3 years
Amount issued and outstanding			25,000,000	25,000,000				50,000,000
Interest rate, stated percentage			1.94%	2.51%				3.25%	3.15%
Line of credit facility, remaining borrowing capacity					100,000,000
Proceeds from issuance of long-term debt									50,000,000
Sale leaseback transaction, gross proceeds									$ 7,600,000	$ 7,100,000