LONG-TERM DEBT (Details) - USD ($)	1 Months Ended			12 Months Ended
	Aug. 31, 2016	Jul. 31, 2016	Jan. 31, 2016	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015	Oct. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2011
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				$ 1,047,482,000		$ 1,035,848,000
Less Current Maturities				(231,909,000)		(29,454,000)
Total Long-Term Debt				815,573,000		1,006,394,000
Long-term Debt, Fiscal Year Maturity [Abstract]
2017				231,909,000
2018				38,909,000
2019				258,909,000
2020				67,909,000
2021				52,909,000
Amount of facility				660,000,000	$ 50,000,000
Unamortized debt issuance costs				$ 7,600,000		9,000,000
Energenic
Long-term Debt, Fiscal Year Maturity [Abstract]
Equity interest										50.00%
Senior notes | Series Notes at variable rates due 2019
Long-term Debt, Fiscal Year Maturity [Abstract]
Interest rate at period end				2.32%
Medium-term notes
Long-term Debt, Fiscal Year Maturity [Abstract]
Maximum borrowing capacity						400,000,000.0
South Jersey Gas Company
Long-term Debt, Fiscal Year Maturity [Abstract]
Amount of facility				$ 210,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2016
Debt Instrument [Line Items]
Stated interest rate	5.437%			5.437%
Total Long-Term Debt Outstanding				$ 0		10,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Amount of debt retired	$ 10,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2016
Debt Instrument [Line Items]
Stated interest rate		4.60%		4.60%
Total Long-Term Debt Outstanding				$ 0		17,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Amount of debt retired		$ 17,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2017
Debt Instrument [Line Items]
Stated interest rate				4.657%
Total Long-Term Debt Outstanding				$ 15,000,000		15,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2018
Debt Instrument [Line Items]
Stated interest rate				7.97%
Total Long-Term Debt Outstanding				$ 10,000,000		10,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2018
Debt Instrument [Line Items]
Stated interest rate				7.125%
Total Long-Term Debt Outstanding				$ 20,000,000		20,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2019
Debt Instrument [Line Items]
Stated interest rate				5.587%
Total Long-Term Debt Outstanding				$ 10,000,000		10,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2024 (D)
Debt Instrument [Line Items]
Stated interest rate				3.00%
Total Long-Term Debt Outstanding				$ 50,000,000		50,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Annual payment				$ 10,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2024 (E)
Debt Instrument [Line Items]
Stated interest rate				3.03%
Total Long-Term Debt Outstanding				$ 35,000,000		35,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Annual payment				$ 7,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2025
Debt Instrument [Line Items]
Stated interest rate				3.63%
Total Long-Term Debt Outstanding				$ 8,182,000		9,091,000
Less Current Maturities				(900,000)
Long-term Debt, Fiscal Year Maturity [Abstract]
Payment towards principal				$ 900,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2026 (G)
Debt Instrument [Line Items]
Stated interest rate				4.84%
Total Long-Term Debt Outstanding				$ 15,000,000		15,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Annual payment				$ 2,500,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2026 (H)
Debt Instrument [Line Items]
Stated interest rate				4.93%
Total Long-Term Debt Outstanding				$ 45,000,000		45,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Annual payment				$ 7,500,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2027
Debt Instrument [Line Items]
Stated interest rate				4.03%
Total Long-Term Debt Outstanding				$ 45,000,000		45,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2030 (I)
Debt Instrument [Line Items]
Stated interest rate				4.01%
Total Long-Term Debt Outstanding				$ 50,000,000		50,000,000
South Jersey Gas Company | First Mortgage Bonds | MTN, 4.01%, Due November 2018 and November 2019
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				8,000,000
South Jersey Gas Company | First Mortgage Bonds | MTN, 4.01%, due November 2025
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				2,000,000
South Jersey Gas Company | First Mortgage Bonds | MTN, 4.01%, due November 2026
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				3,000,000
South Jersey Gas Company | First Mortgage Bonds | MTN, 4.01%, due November 2027
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				8,000,000
South Jersey Gas Company | First Mortgage Bonds | MTN, 4.01%, due November 2028, November 2029 and November 2030
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				$ 7,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2030
Debt Instrument [Line Items]
Stated interest rate				4.23%
Total Long-Term Debt Outstanding				$ 30,000,000		30,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2032
Debt Instrument [Line Items]
Stated interest rate				3.74%
Total Long-Term Debt Outstanding				$ 35,000,000		35,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2033
Debt Instrument [Line Items]
Stated interest rate				5.55%
Total Long-Term Debt Outstanding				$ 32,000,000		32,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2034
Debt Instrument [Line Items]
Stated interest rate				6.213%
Total Long-Term Debt Outstanding				$ 10,000,000		10,000,000
South Jersey Gas Company | First Mortgage Bonds | Series due 2035
Debt Instrument [Line Items]
Stated interest rate				5.45%
Total Long-Term Debt Outstanding				$ 10,000,000		10,000,000
South Jersey Gas Company | Unsecured debt | Series A 2006 Bonds at variable rates due 2036
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				$ 24,900,000		24,900,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Interest rate at period end				0.74%
South Jersey Gas Company | Loans payable | Term facility
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				$ 200,000,000		139,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Amount of facility				200,000,000
Line of credit balance				200,000,000		$ 139,000,000
Average interest rate			1.41%			1.17%
Issuance of additional long-term debt			$ 61,000,000
Marina Energy LLC | Energenic
Long-term Debt, Fiscal Year Maturity [Abstract]
Equity interest								50.00%
Marina Energy LLC | Unsecured debt
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				61,400,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Outstanding amount of note not fixed by interest rate derivatives				$ 46,100,000
Fixed interest rate				4.22%
Marina Energy LLC | Unsecured debt | Series A 2001 Bonds at variable rates due 2031
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				$ 20,000,000		$ 20,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Interest rate at period end				0.72%
Marina Energy LLC | Unsecured debt | Series B 2001 Bonds at variable rates due 2021
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				$ 25,000,000		25,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Interest rate at period end				0.73%
Marina Energy LLC | Unsecured debt | Series A 2006 Bonds at variable rates due 2036
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				$ 16,400,000		16,400,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Interest rate at period end				0.72%
South Jersey Industries Inc.
Long-term Debt, Fiscal Year Maturity [Abstract]
Amount of facility				$ 450,000,000
South Jersey Industries Inc. | Unsecured debt | South Jersey Industries Term Loan at variable rates due 2020
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				$ 50,000,000		50,000,000
South Jersey Industries Inc. | Unsecured debt | Term loan due 2015 | Term facility
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding							$ 50,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Interest rate at period end				1.79%
South Jersey Industries Inc. | Senior notes | Series B 2012 Notes due 2017
Debt Instrument [Line Items]
Stated interest rate				2.71%
Total Long-Term Debt Outstanding				$ 16,000,000		16,000,000
Less Current Maturities				$ (16,000,000)
South Jersey Industries Inc. | Senior notes | Series due 2019
Debt Instrument [Line Items]
Stated interest rate				3.05%
Total Long-Term Debt Outstanding				$ 60,000,000		60,000,000
South Jersey Industries Inc. | Senior notes | Series due 2019
Debt Instrument [Line Items]
Stated interest rate				3.05%
Total Long-Term Debt Outstanding				$ 30,000,000		30,000,000
South Jersey Industries Inc. | Senior notes | Series due 2019
Debt Instrument [Line Items]
Stated interest rate				3.05%
Total Long-Term Debt Outstanding				$ 50,000,000		50,000,000
South Jersey Industries Inc. | Senior notes | Series C 2012 Notes due 2022
Debt Instrument [Line Items]
Stated interest rate				3.46%
Total Long-Term Debt Outstanding				$ 35,000,000		35,000,000
South Jersey Industries Inc. | Senior notes | Series Notes at variable rates due 2019
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				40,000,000		40,000,000
South Jersey Industries Inc. | Senior notes | Series Notes at variable rates due 2019
Debt Instrument [Line Items]
Total Long-Term Debt Outstanding				$ 60,000,000		60,000,000
ACB Energy Partners, LLC | Loan and security agreement | Loan & Security Agreement
Debt Instrument [Line Items]
Stated interest rate				7.60%
Total Long-Term Debt Outstanding				$ 0		12,735,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Maximum borrowing capacity				$ 16,000,000
Payment to retire outstanding debt			$ 12,700,000
ACLE | Debt agreement | Debt Agreement Due 2020, 4.83%, Agreement 1
Debt Instrument [Line Items]
Stated interest rate				4.83%
Total Long-Term Debt Outstanding				$ 0		3,551,000
SCLE | Debt agreement | Debt Agreement Due 2020, 4.83%, Agreement 2
Debt Instrument [Line Items]
Stated interest rate				4.83%
Total Long-Term Debt Outstanding				$ 0		1,738,000
SXLE | Debt agreement | Debt Agreement Due 2020, 4.83%, Agreement 3
Debt Instrument [Line Items]
Stated interest rate				4.83%
Total Long-Term Debt Outstanding				$ 0		3,433,000
ACLE, SCLE and SXLE | Debt agreement
Debt Instrument [Line Items]
Stated interest rate									4.83%
Total Long-Term Debt Outstanding						$ 8,700,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Maximum borrowing capacity									$ 10,000,000
Payment to retire outstanding debt	$ 8,300,000