PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost		$ 1,112,000	$ 1,106,000	$ 2,494,000	$ 2,421,000
Interest Cost		2,931,000	3,062,000	5,886,000	6,062,000
Expected Return on Plan Assets		(3,529,000)	(3,374,000)	(7,053,000)	(6,754,000)
Amortizations:
Prior Service Cost		33,000	53,000	66,000	106,000
Actuarial Loss		2,528,000	2,388,000	5,141,000	4,697,000
Net Periodic Benefit Cost		3,075,000	3,235,000	6,534,000	6,532,000
Capitalized Benefit Cost		(1,129,000)	(1,213,000)	(2,400,000)	(2,400,000)
Deferred Benefit Cost		(139,000)	(161,000)	(300,000)	(322,000)
Total Net Periodic Benefit Expense		1,807,000	1,861,000	3,834,000	3,810,000
Contributions	$ 10,000,000				0
Estimated future contributions		0		0
Pension Benefits | South Jersey Gas Company
Amortizations:
Net Periodic Benefit Cost		2,300,000	2,300,000	4,800,000	4,800,000
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		208,000	195,000	455,000	425,000
Interest Cost		609,000	654,000	1,209,000	1,307,000
Expected Return on Plan Assets		(853,000)	(776,000)	(1,705,000)	(1,552,000)
Amortizations:
Prior Service Cost		(86,000)	(86,000)	(172,000)	(172,000)
Actuarial Loss		307,000	261,000	619,000	555,000
Net Periodic Benefit Cost		185,000	248,000	406,000	563,000
Capitalized Benefit Cost		(46,000)	(45,000)	(101,000)	(146,000)
Total Net Periodic Benefit Expense		139,000	203,000	305,000	417,000
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	200,000	$ 300,000
Supplemental executive retirement plan
Amortizations:
Estimated future contributions		$ 2,500,000		$ 2,500,000