DERIVATIVE INSTRUMENTS - BROKER MARGIN DEPOSITS (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Sep. 30, 2013
Broker margin - Current assets	$ 38,490	$ 6,581
Broker margin - Current (liabilities)	(10,573)	0
NJNG [Member]
Broker margin - Current assets	0	213
Broker margin - Current (liabilities)	(10,573)	0
NJRES [Member]
Broker margin - Current assets	$ 38,490	$ 6,368