CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Net Cash Provided by Operating Activities	$ 254,200,000	$ 121,416,000
Cash Flows from Investing Activities:
Capital Expenditures	(344,828,000)	(357,844,000)
Acquisition-related Working Capital Settlement	0	15,600,000
Cash Paid for Acquisition, Net of Cash Acquired	(10,932,000)	(3,952,000)
Proceeds from Dispositions and Sale of Property, Plant & Equipment	119,948,000	26,360,000
Investment in Long-Term Receivables	(18,787,000)	(10,939,000)
Proceeds from Long-Term Receivables	10,457,000	7,604,000
Proceeds from Company-Owned Life Insurance	0	1,694,000
Investment in Affiliates	(1,353,000)	(4,102,000)
Advances to Affiliates	0	(1,902,000)
Net Repayment of Notes Receivable - Affiliates	2,504,000	0
Investment in Subsidiary, Net of Cash Acquired	(54,328,000)	0
Net Cash Used in Investing Activities	(297,319,000)	(327,481,000)
Cash Flows from Financing Activities:
Net (Repayments of) Borrowings from Short-Term Credit Facilities	(251,700,000)	541,800,000
Proceeds from Issuance of Long-Term Debt	800,000,000	244,657,000
Principal Repayments of Long-Term Debt	(660,000,000)	(725,000,000)
Payments for Issuance of Long-Term Debt	(6,810,000)	(2,106,000)
Dividends on Common Stock	(54,553,000)	(53,124,000)
Proceeds from Sale of Common Stock	200,000,000	189,032,000
Payments for the Issuance of Common Stock	(1,897,000)	0
Net Cash Provided by Financing Activities	25,040,000	195,259,000
Net Decrease in Cash, Cash Equivalents and Restricted Cash	(18,079,000)	(10,806,000)
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	28,381,000	31,679,000
Cash, Cash Equivalents and Restricted Cash at End of Period	10,302,000	20,873,000
SJG
Net Cash Provided by Operating Activities	158,813,000	114,482,000
Cash Flows from Investing Activities:
Capital Expenditures	(188,173,000)	(178,666,000)
Investment in Long-Term Receivables	(18,787,000)	(10,939,000)
Proceeds from Long-Term Receivables	10,457,000	7,604,000
Net Cash Used in Investing Activities	(196,503,000)	(182,001,000)
Cash Flows from Financing Activities:
Net (Repayments of) Borrowings from Short-Term Credit Facilities	(63,400,000)	67,700,000
Proceeds from Issuance of Long-Term Debt	400,000,000	10,000,000
Principal Repayments of Long-Term Debt	(410,000,000)	(10,000,000)
Payments for Issuance of Long-Term Debt	(3,434,000)	(12,000)
Additional Investment by Shareholder	109,500,000	0
Net Cash Provided by Financing Activities	32,666,000	67,688,000
Net Decrease in Cash, Cash Equivalents and Restricted Cash	(5,024,000)	169,000
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	6,751,000	3,262,000
Cash, Cash Equivalents and Restricted Cash at End of Period	$ 1,727,000	$ 3,431,000