LEASES - Lease Maturity and Balance Sheet Information (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019
SJI Consolidated
2019 (excluding the three months ended March 31, 2019)	$ 1,298
2020	1,081
2021	233
2022	65
2023	34
Thereafter	114
Total future minimum lease payments	2,825
Less imputed interest	100
Total lease payments	2,725	$ 3,100
Included in the condensed consolidated balance sheet
Current lease liabilities (included in Other Current Liabilities)	1,644
Long-term lease liabilities (included in Other Noncurrent Liabilities)	1,081
SJG Utility Operations
SJI Consolidated
2019 (excluding the three months ended March 31, 2019)	145
2020	151
2021	39
2022	21
2023	19
Thereafter	114
Total future minimum lease payments	489
Less imputed interest	41
Total lease payments	448	$ 500
Included in the condensed consolidated balance sheet
Current lease liabilities (included in Other Current Liabilities)	178
Long-term lease liabilities (included in Other Noncurrent Liabilities)	$ 270