DERIVATIVE INSTRUMENTS - OUTSTANDING CONTRACTS (Details) $ in Thousands, MMcfe in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) MMcfe	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Derivative [Line Items]
Unrealized gain (loss) on energy-related commodity contracts | $	$ 0	$ 4,760	$ (2,798)
Not Designated as Hedging Instrument
Derivative [Line Items]
Gains (losses) on energy-related commodity contracts | $	$ 5,567	385	$ (11,748)
Energy Related Derivative, Natural Gas | Not Designated as Hedging Instrument | Purchases
Derivative [Line Items]
Notional derivative amount	96.7
Energy Related Derivative, Natural Gas | Not Designated as Hedging Instrument | Sales
Derivative [Line Items]
Notional derivative amount	130.2
Energy Related Derivative, Natural Gas | South Jersey Gas Company | Not Designated as Hedging Instrument | Purchases
Derivative [Line Items]
Notional derivative amount	10.3
Energy Related Derivative, Natural Gas | South Jersey Gas Company | Not Designated as Hedging Instrument | Sales
Derivative [Line Items]
Notional derivative amount	0.8
Basis And Index Contracts | Not Designated as Hedging Instrument
Derivative [Line Items]
Notional derivative amount	72.1
Basis And Index Contracts | South Jersey Gas Company | Not Designated as Hedging Instrument
Derivative [Line Items]
Notional derivative amount	1.5
Energy Related Derivative
Derivative [Line Items]
Unrealized gain (loss) on energy-related commodity contracts | $	$ 22,100	2,400
Energy Related Derivative | South Jersey Gas Company
Derivative [Line Items]
Unrealized gain (loss) on energy-related commodity contracts | $	$ 7,100	$ 1,100