RATES AND REGULATORY ACTIONS (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Feb. 29, 2020
Assets held for sale
Schedule of Capitalization [Line Items]
Consideration received on sales or projects			$ 7,200	$ 16,100
ELK Utility Operations | Assets held for sale
Schedule of Capitalization [Line Items]
Consideration received on sales or projects		$ 15,000
ETG Utility Operations
Schedule of Capitalization [Line Items]
Regulatory liability	$ 172,959	168,436	172,959
Regulatory assets	181,086	169,231	181,086
SJG
Schedule of Capitalization [Line Items]
Regulatory liability	257,539	274,482	257,539
Regulatory assets	518,184	$ 496,177	518,184
New Jersey Board of Public Utilities | SJG
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)	$ 75,300
Approved rate of return on rate base, percentage	7.34%
Approved return on common equity, percentage	10.40%
Approved common equity component, percentage	54.18%
Project abandonment costs			10,100
Stipulation of Settlement | SJG
Schedule of Capitalization [Line Items]
Public utilities bill credit			800
Stipulation of Settlement | SJG | Protected Excess Deferred Income Tax
Schedule of Capitalization [Line Items]
Net regulatory liability	$ 149,400		149,400
Regulatory liability	181,000		181,000
Regulatory assets	31,600		31,600
Stipulation of Settlement | SJG | Unprotected Excess Deferred Income Tax
Schedule of Capitalization [Line Items]
Credits due to customers under conditions of approval	$ 44,700		44,700
Public utilities, customer refund term (in years)	5 years
Annual RAC Rate Adjustment | ETG Utility Operations
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)			6,100
Approved rate increase (decrease)			6,000
Annual EEP Rate Adjustment | ETG Utility Operations
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)			1,000
Approved rate increase (decrease)			$ 900
Annual EEP Rate Adjustment | New Jersey Board of Public Utilities | ETG Utility Operations
Schedule of Capitalization [Line Items]
Public utilities budget					$ 4,200