ASSET RETIREMENT OBLIGATIONS (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Estimated Accretion
2018	$ 1,557
2019	1,627
2020	1,702
2021	1,778
2022	1,863
Total	8,527
Natural Gas Distribution
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at period beginning	24,825	$ 23,521
Accretion	1,366	1,304
Additions	1,880	729
Revisions in estimated cash flows	(2,133)	(245)
Retirements	(298)	(484)
Reclassification to held for sale or sold	0	0
Balance at period end	25,640	24,825
Clean Energy Ventures
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at period beginning	6,595	4,858
Accretion	198	245
Additions	517	1,492
Revisions in estimated cash flows	0	0
Retirements	0	0
Reclassification to held for sale or sold	(4,262)	0
Balance at period end	$ 3,048	$ 6,595