PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 31, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost		$ 1,247,000	$ 1,210,000	$ 3,741,000	$ 3,632,000
Interest Cost		2,943,000	3,031,000	8,829,000	9,094,000
Expected Return on Plan Assets		(3,526,000)	(3,377,000)	(10,579,000)	(10,131,000)
Amortizations:
Prior Service Cost		33,000	53,000	98,000	158,000
Actuarial Loss		2,570,000	2,349,000	7,712,000	7,046,000
Net Periodic Benefit Cost		3,267,000	3,266,000	9,801,000	9,799,000
Capitalized Benefit Cost		(1,143,000)	(1,251,000)	(3,542,000)	(3,651,000)
Deferred Benefit Cost		(95,000)	(161,000)	(395,000)	(484,000)
Total Net Periodic Benefit Expense		2,029,000	1,854,000	5,864,000	5,664,000
Contributions	$ 10,000,000				0
Estimated future contributions		0		0
Pension Benefits | South Jersey Gas Company
Amortizations:
Net Periodic Benefit Cost		2,300,000	2,400,000	7,100,000	7,200,000
Contributions	$ 8,000,000
Estimated future contributions		0		0
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost		228,000	213,000	683,000	638,000
Interest Cost		604,000	654,000	1,813,000	1,961,000
Expected Return on Plan Assets		(853,000)	(776,000)	(2,558,000)	(2,328,000)
Amortizations:
Prior Service Cost		(86,000)	(86,000)	(258,000)	(258,000)
Actuarial Loss		310,000	277,000	928,000	832,000
Net Periodic Benefit Cost		203,000	282,000	608,000	845,000
Capitalized Benefit Cost		66,000	(73,000)	(35,000)	(219,000)
Total Net Periodic Benefit Expense		269,000	209,000	573,000	626,000
Defined benefit plan regulatory obligation to contribute to the plan during the period		3,600,000		3,600,000
Other Postretirement Benefits | South Jersey Gas Company
Amortizations:
Net Periodic Benefit Cost		(100,000)	$ 100,000	100,000	$ 400,000
Supplemental executive retirement plan
Amortizations:
Estimated future contributions		$ 2,500,000		$ 2,500,000