RATES AND REGULATORY ACTIONS (Details) - USD ($) $ in Thousands		1 Months Ended					9 Months Ended
	Apr. 01, 2021	Sep. 30, 2021	Jun. 30, 2021	May 31, 2021	Apr. 30, 2021	Jan. 31, 2021	Sep. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
ETG Utility Operations
Schedule of Capitalization [Line Items]
Regulatory liability		$ 195,242					$ 195,242		$ 175,217
ETG Utility Operations | Annual USF Petition
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)		3,500
Requested revenue increase (decrease)							7,100
ETG Utility Operations | Annual BGSS Filing
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)							14,000
ETG Utility Operations | WNC and CEP Filings
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)		5,300
ETG Utility Operations | Annual RAC Filing
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)							(7,900)
ETG Utility Operations | Annual Legacy EEP Program Filing
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)							(1,600)
SJG
Schedule of Capitalization [Line Items]
Regulatory liability		223,180					223,180		245,360
Public utilities, property, plant and equipment		2,909,427					2,909,427		$ 2,780,906
SJG | SHARP II
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)		2,200
Investment amount		22,600					22,600
SJG | Annual USF Petition
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)		$ 3,800
SJG | IIP Investments
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)							$ 742,500
Requested rate period							5 years
SJG | Annual BGSS Filing
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)							$ 59,500
SJG | Annual CIP Filing
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)							15,300
SJG | Accelerated Infrastructure Replacement Program
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)							5,700
Public Utilities, Requested Rate Increase (Decrease), Amount, Total							58,700
SJG | Tax Reform
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)							11,600
SJG | Annual EET Filing
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)							12,800
SJG | Annual SBC and TIC Filing
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)							$ 900
SJG | Pricing dispute, long-term gas supply contract | Settled Litigation
Schedule of Capitalization [Line Items]
Recovery period				2 years
Recovery of costs				$ 22,900
New Jersey Board of Public Utilities | ETG Utility Operations
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)	$ (3,200)
New Jersey Board of Public Utilities | ETG Utility Operations | IIP Investments
Schedule of Capitalization [Line Items]
Public utilities, property, plant and equipment			$ 63,800
Annual EET Rate Adjustment | SJG
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)						$ 5,900
Annual Tax Act Rider | SJG | Protected Excess Deferred Income Tax
Schedule of Capitalization [Line Items]
Regulatory liability								$ 14,900
Societal Benefits Clause | New Jersey Board of Public Utilities | SJG
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)					$ 5,500
Annual EEP Rate Adjustment | ETG Utility Operations
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)			$ (500)
Annual EEP Rate Adjustment | New Jersey Board of Public Utilities | SJG
Schedule of Capitalization [Line Items]
Approved rate period					3 years
Public utilities, property, plant and equipment					$ 133,300
Requested revenue increase (decrease)					5,400
Annual EEP Rate Adjustment | New Jersey Board of Public Utilities | ETG Utility Operations
Schedule of Capitalization [Line Items]
Public utilities, property, plant and equipment					83,400
Requested revenue increase (decrease)					$ 2,800