RATES AND REGULATORY ACTIONS (Details) - USD ($)	1 Months Ended						3 Months Ended		9 Months Ended
	Sep. 30, 2019	Jul. 31, 2019	Jun. 30, 2019	May 31, 2019	Apr. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Schedule of Capitalization [Line Items]
Impairment charge							$ 1,300,000		$ 1,300,000	$ 99,200,000
ETG Utility Operations
Schedule of Capitalization [Line Items]
Net plant additions not reflected in current rates					$ 346,000,000.0
SJG
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)								$ 3,900,000
Impairment charge							$ 0	$ 0	$ 0	$ 0
New Jersey Board of Public Utilities | ETG Utility Operations
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)					65,000,000.0
Requested recovery of investment costs not yet approved			$ 300,000,000.0
New Jersey Board of Public Utilities | SJG
Schedule of Capitalization [Line Items]
Investment to be recovered by Sharp II	$ 27,400,000
Annual BGSS Filing | SJG
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)						$ 65,500,000
Stipulation of Settlement | SJG
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)					$ 65,500,000
Period of gas cost recovery					2 years
Public utilities bill credit					$ 24,000,000.0
Annual EET Rate Adjustments | SJG
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)			1,300,000
Annual Tax Rider | SJG
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)			6,800,000
Annual BGSS Revenues | SJG
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)	27,600,000
Conservation Incentive Program | SJG
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)	7,600,000
Accelerated Infrastructure Replacement Program II | SJG
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)	6,700,000
Regulatory investment to be recovered By AIRP II	64,500,000
SHARP II | SJG
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)	2,900,000
Annual USF Recoveries | SJG
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)	$ 1,000,000.0
Annual EEP Rate Adjustment | ETG Utility Operations
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)					$ 1,300,000
Requested revenue increase (decrease)		$ 1,000,000.0
Annual RAC Rate Adjustment | ETG Utility Operations
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)				$ 6,900,000
RAC Rate Adjustment Petition | ETG Utility Operations
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)		6,100,000
WNC/OCP/OSMC Rate Adjustment Petition | ETG Utility Operations
Schedule of Capitalization [Line Items]
Requested revenue increase (decrease)		$ 1,900,000
Annual USF Petition | ETG Utility Operations
Schedule of Capitalization [Line Items]
Approved rate increase (decrease)			$ 800,000