DEBT - LONG TERM DEBT (Details) - USD ($)	1 Months Ended		6 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2021	Mar. 31, 2020
Debt Instrument [Line Items]
Proceeds from sale leaseback transaction			$ 0	$ 4,000,000
Proceeds from sale leaseback transaction - solar	$ 12,100,000		$ 12,124,000	0
Clean Energy Ventures | Minimum
Debt Instrument [Line Items]
Sale leaseback transaction lease term			5 years
Clean Energy Ventures | Maximum
Debt Instrument [Line Items]
Sale leaseback transaction lease term			15 years
NJNG
Debt Instrument [Line Items]
Proceeds from sale leaseback transaction		$ 4,000,000.0	$ 0
Final principal payments for early purchase options			$ 1,200,000	$ 1,200,000