RATES AND REGULATORY ACTIONS (Details) - USD ($) $ in Thousands	1 Months Ended				3 Months Ended
	Jun. 30, 2020	May 31, 2020	Apr. 30, 2020	Mar. 31, 2020	Mar. 31, 2020	Feb. 29, 2020	Dec. 31, 2019
ETG Utility Operations
Schedule of Capitalization [Line Items]
Regulatory liability	$ 178,919						$ 168,436
Regulatory assets	163,177						169,231
ETG Utility Operations | Annual BGSS Filing
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)	(15,500)
ETG Utility Operations | Annual USF Petition
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)	(300)
SJG
Schedule of Capitalization [Line Items]
Regulatory liability	255,229						274,482
Regulatory assets	485,354						$ 496,177
Public utilities, annual revenue increase (decrease)	(11,800)
SJG | Annual BGSS Filing
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)	(39,200)
SJG | Annual CIP Filing
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)	27,400
SJG | Annual USF Petition
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)	(300)
New Jersey Board of Public Utilities | ETG Utility Operations | IIP Investments
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)			$ 6,500
Public utilities, property, plant and equipment			60,000
New Jersey Board of Public Utilities | SJG
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)		$ 75,700
Approved rate of return on rate base, percentage		7.40%
Approved return on common equity, percentage		10.40%
Approved common equity component, percentage		54.20%
New Jersey Board of Public Utilities | SJG | AIRP II Investments
Schedule of Capitalization [Line Items]
Public utilities, property, plant and equipment			59,500
New Jersey Board of Public Utilities | SJG | SHARP II Investments
Schedule of Capitalization [Line Items]
Public utilities, property, plant and equipment			34,200
AIRP II | New Jersey Board of Public Utilities | SJG
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)			6,500
SHARP II | New Jersey Board of Public Utilities | SJG
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)			$ 3,800
Stipulation of Settlement | SJG | Annual BGSS Filing
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 Tax Act Rider | SJG
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)	14,900
Annual EET Rate Adjustment | SJG
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)	$ 5,900
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