FINANCIAL INSTRUMENTS (Details) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($) term	Jun. 30, 2015 USD ($) term	Dec. 31, 2011	Dec. 31, 2014 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Restricted investments held In escrow	$ 2,600	$ 2,600		$ 1,700
Margin accounts with selected counterparties to support risk management activities	51,100	51,100		63,700
Investment in Affiliates	51,970	51,970		68,351
Notes Receivable - Affiliate	36,300	36,300		36,799
South Jersey Gas Company | Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Long-term receivables, net of unamortized discount	14,000	14,000		15,000
Imputed interest on long term receivables	1,100	1,100		$ 1,300
Atlantic City Note Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable with Imputed Interest, Face Amount	$ 10,000	$ 10,000
Receivable with Imputed Interest, Effective Yield (Interest Rate)	1.00%
Receivable With Imputed Interest, Term	6 months
Receivable With Imputed Interest, Number Of Additional Terms | term	2	2
Receivable With Imputed Interest, Extension Term	3 months
Energenic US LLC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Equity interest	50.00%	50.00%
Contract term (in years)			20 years
Equity Method Investment, Other than Temporary Impairment		$ 7,700
Investment in Affiliates	$ 2,200	2,200
Notes Receivable - Affiliate	$ 13,900	$ 13,900