DERIVATIVE INSTRUMENTS - BROKER MARGIN DEPOSITS (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Sep. 30, 2013
Broker margin - Current assets	$ 27,904	$ 6,581
Broker margin - Current (liabilities)	(2,278)	0
NJNG [Member]
Broker margin - Current assets	0	213
Broker margin - Current (liabilities)	(2,278)	0
NJRES [Member]
Broker margin - Current assets	$ 27,904	$ 6,368