REVENUE - Accounts Receivable (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Accounts Receivable
Disaggregation of Revenue [Line Items]
Contracts with customers, asset	$ 352,437	$ 272,286	$ 343,835	$ 278,723
Increase (decrease) in contracts with customers, asset	8,602	(6,437)
Unbilled Revenue
Disaggregation of Revenue [Line Items]
Contracts with customers, asset	22,021	26,783	87,357	85,423
Increase (decrease) in contracts with customers, asset	(65,336)	(58,640)
SJG | Accounts Receivable
Disaggregation of Revenue [Line Items]
Contracts with customers, asset	99,727	83,031	125,848	88,657
Increase (decrease) in contracts with customers, asset	(26,121)	(5,626)
SJG | Unbilled Revenue
Disaggregation of Revenue [Line Items]
Contracts with customers, asset	11,258	8,288	$ 43,236	$ 46,837
Increase (decrease) in contracts with customers, asset	$ (31,978)	$ (38,549)