DERIVATIVE INSTRUMENTS - BROKER MARGIN DEPOSITS (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Broker margin - Current assets	$ 59,313	$ 6,581
Broker margin - Current (liabilities)	(5,987)	0
NJNG [Member]
Broker margin - Current assets	0	213
Broker margin - Current (liabilities)	(5,987)	0
NJRES [Member]
Broker margin - Current assets	$ 59,313	$ 6,368