INCOME TAXES, DEFERRED TAX ASSETS AND LIABILITIES (Details) - USD ($) $ in Thousands		Sep. 30, 2016	Sep. 30, 2015
Deferred tax assets
Investment tax credits	[1]	$ 76,517	$ 24,770
Deferred service contract revenue		3,601	3,440
Incentive compensation		8,128	10,369
Fair value of derivatives		1,179	0
Federal net operating losses		27,541	0
State net operating losses		18,113	12,757
Conservation incentive plan		0	2,091
Underrecovered gas costs		3,831	2,827
Other		11,668	12,762
Total deferred tax assets		150,578	69,016
Deferred tax liabilities
Property related items		(532,027)	(440,420)
Remediation costs		(7,928)	(7,641)
Equity investments		(37,740)	(37,930)
Postemployment benefits		(7,902)	(2,976)
Fair value of derivatives		0	(3,180)
Conservation incentive plan		(14,953)	0
Other		(14,610)	(13,409)
Total deferred tax liabilities		(615,160)	(505,556)
Total net deferred tax liabilities		(464,582)	(436,540)
NJNG
Deferred tax assets
Investment tax credits		2,500	2,700
NJRCEV
Deferred tax liabilities
Tax credit carryforward		$ 74,000	$ 22,100

[1] Includes $2.5 million and $2.7 million for NJNG for fiscal 2016 and fiscal 2015, respectively, which is being amortized over the life of the related assets, and $74 million and $22.1 million for NJRCEV for fiscal 2016 and fiscal 2015, respectively, which is ITC carryforward.