Schedule II - Valuation and Qualifying Accounts (Details) - Provision for Uncollectible Accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 13,988	$ 12,744	$ 10,252
Charged to Costs and Expenses	7,977	6,949	6,907
Acquisition Adjustments	6,579	0	0
Charged to Other Accounts	(466)	(394)	(47)
Deductions	9,236	5,311	4,368
Balance at End of Period	18,842	13,988	12,744
South Jersey Gas Company
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	13,799	12,570	9,778
Charged to Costs and Expenses	7,997	6,949	6,993
Charged to Other Accounts	(466)	(394)	(47)
Deductions	7,687	5,326	4,154
Balance at End of Period	$ 13,643	$ 13,799	$ 12,570