LEASES - Lease Maturity and Balance Sheet Information (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019
SJI Consolidated
2019 (excluding the nine months ended September 30, 2019)	$ 414
2020	1,075
2021	233
2022	65
2023	34
Thereafter	114
Total future minimum lease payments	1,935
Less imputed interest	64
Total lease payments	1,871	$ 3,100
Included in the condensed consolidated balance sheet
Current lease liabilities (included in Other Current Liabilities)	1,326
Long-term lease liabilities (included in Other Noncurrent Liabilities)	545
SJG
SJI Consolidated
2019 (excluding the nine months ended September 30, 2019)	43
2020	150
2021	39
2022	21
2023	19
Thereafter	114
Total future minimum lease payments	386
Less imputed interest	32
Total lease payments	354	$ 500
Included in the condensed consolidated balance sheet
Current lease liabilities (included in Other Current Liabilities)	166
Long-term lease liabilities (included in Other Noncurrent Liabilities)	$ 188