CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash Flows from Operating Activities
Net Income	$ 51,181	$ 46,893
Adjustments to Reconcile Net Income to Net Cash Flows from Operating Activities:
Depreciation Expense	55,604	47,140
Amortization Expense	7,736	9,691
Amortization of Debt Issuance Costs	763	782
Use of Renewable Energy Credits for Compliance	11,984	11,402
Deferred Income Taxes	5,590	4,657
Pension and Other Postretirement Benefits Expense	4,510	3,794
Pension and Other Postretirement Benefits Funding	(953)	(1,186)
Allowance for Equity Funds Used During Construction	(5,252)	(2,893)
Changes in Current Assets and Current Liabilities:
Accounts Receivable	26,817	133,058
Materials, Supplies, and Fuel Inventory	(3,350)	(10,040)
Regulatory Assets	48,234	294
Other Current Assets	(1,930)	(887)
Accounts Payable and Accrued Charges	24,007	(104,341)
Income Taxes Receivable/Payable	(688)	(777)
Regulatory Liabilities	(3,703)	(2,818)
Other, Net	(30,448)	(13,858)
Net Cash Flows—Operating Activities	190,102	120,911
Cash Flows from Investing Activities
Capital Expenditures	(133,283)	(116,683)
Purchase Intangibles, Renewable Energy Credits	(11,956)	(12,961)
Contributions in Aid of Construction	965	799
Net Cash Flows—Investing Activities	(144,274)	(128,845)
Cash Flows from Financing Activities
Proceeds from Borrowings, Revolving Credit Facility	15,000	0
Repayments of Borrowings, Revolving Credit Facility	(15,000)	0
Proceeds from Issuance, Long-Term Debt—Net of Discount	0	373,954
Repayments of Long-Term Debt	0	(240,745)
Payment of Debt Issuance Costs	0	(3,738)
Contribution from Parent	0	5,900
Other, Net	317	(560)
Net Cash Flows—Financing Activities	317	134,811
Net Increase (Decrease) in Cash, Cash Equivalents, and Restricted Cash	46,145	126,877
Cash, Cash Equivalents, and Restricted Cash, Beginning of Period	42,595	50,981
Cash, Cash Equivalents, and Restricted Cash, End of Period	$ 88,740	$ 177,858