LINES OF CREDIT (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Line of Credit Facility [Line Items]
Total Facility	$ 610,000,000
Usage	286,000,000
Available Liquidity	324,000,000
Letters of credit outstanding	13,600,000
Weighted average borrowing cost	0.88%		1.06%
Average borrowings outstanding during the period	274,100,000		332,200,000
Maximum amounts outstanding during the period	329,400,000		390,700,000
Financial covenant, ratio of indebtedness to consolidated total capitalization	0.65 to 1
Minimum
Line of Credit Facility [Line Items]
Financial covenant, ratio of indebtedness to consolidated total capitalization minimum	0.65
SJG Commercial Paper Program
Line of Credit Facility [Line Items]
Total Facility	200,000,000
Fixed maturities of notes, at maximum number of days (in days)	270 days
South Jersey Gas Company
Line of Credit Facility [Line Items]
Total Facility	210,000,000
Usage	129,600,000
Available Liquidity	80,400,000
South Jersey Gas Company | Revolving Credit Facility
Line of Credit Facility [Line Items]
Total Facility	200,000,000
Usage	129,600,000
Available Liquidity	70,400,000
Expiration Date	May 2018
South Jersey Gas Company | Uncommitted Bank Lines
Line of Credit Facility [Line Items]
Total Facility	10,000,000
Usage	0
Available Liquidity	10,000,000
Expiration Date	August 2015
South Jersey Industries Inc
Line of Credit Facility [Line Items]
Total Facility	400,000,000
Usage	156,400,000
Available Liquidity	243,600,000
South Jersey Industries Inc | Revolving Credit Facility
Line of Credit Facility [Line Items]
Total Facility	400,000,000	[1]
Usage	156,400,000	[1]
Available Liquidity	$ 243,600,000	[1]
Expiration Date	February 2018 (A)	[1]

[1] Includes letters of credit outstanding in the amount of $13.6 million.