Unaudited Condensed Consolidated Balance Sheets - USD ($)	Sep. 30, 2024	Dec. 31, 2023
CURRENT ASSETS:
Cash and cash equivalents	$ 48,308,000	$ 28,579,000
Restricted Cash and Cash Equivalents	5,000
Accounts Receivable, after Allowance for Credit Loss, Current	322,701,000	233,921,000
Accounts Receivable, Allowance for Credit Loss, Current	17,087,000	2,283,000
Inventory, Net	125,090,000	143,590,000
Regulatory assets	126,470,000	89,419,000
Income Taxes Receivable, Current	20,723,000	36,481,000
Derivative Asset	2,817,000	15,682,000
Other Assets, Current	35,936,000	26,358,000
Total current assets	682,045,000	574,030,000
UTILITY PLANT:
Property, Plant and Equipment, Gross	7,560,533,000	7,082,443,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	2,995,834,000	2,954,555,000
Utility plant in service - net	4,564,699,000	4,127,888,000
Construction in Progress, Gross	869,363,000	359,014,000
Total net property, plant and equipment	5,434,062,000	4,486,902,000
Other Assets, Noncurrent [Abstract]
Intangible Assets, Net (Excluding Goodwill)	234,136,000	235,656,000
Regulatory assets	474,963,000	541,784,000
Assets for Plan Benefits, Defined Benefit Plan	39,502,000	41,172,000
Other Assets, Miscellaneous, Noncurrent	168,235,000	301,979,000
Total other non-current assets	916,836,000	1,120,591,000
TOTAL ASSETS	7,032,943,000	6,181,523,000
CURRENT LIABILITIES:
Debt, Current	430,383,000	899,159,000
Accounts payable	278,667,000	292,851,000
Accrued taxes	29,898,000	22,580,000
Interest Payable, Current	83,813,000	33,639,000
Customer deposits	21,319,000	29,308,000
Regulatory Liability, Current	8,322,000	23,371,000
Accrued Liabilities and Other Liabilities	28,548,000	27,547,000
Total current liabilities	907,334,000	1,328,455,000
Long-term Debt and Lease Obligation	3,641,207,000	2,576,798,000
Deferred Income Tax Liabilities, Net	387,512,000	361,488,000
NON-CURRENT LIABILITIES:
Regulatory Liability, Noncurrent	443,691,000	527,224,000
Accrued other postretirement benefits	2,946,000	2,776,000
Asset retirement obligations, non-current	320,166,000	249,930,000
Other non-current liabilities	19,726,000	5,130,000
Total non-current liabilities	4,815,248,000	3,723,346,000
Liabilities	$ 5,722,582,000	$ 5,051,801,000
Common Stock, Shares, Outstanding	108,907,000	108,907,318
Common Stock, Shares Authorized	290,000,000
Common shareholders' equity:
Additional Paid in Capital	$ 1,172,058,000	$ 1,021,992,000
Accumulated Other Comprehensive Income (Loss), Net of Tax	35,812,000	29,294,000
Accumulated deficit	28,932,000	25,182,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,310,361,000	1,129,722,000
Equity, Attributable to Noncontrolling Interest	73,559,000	53,254,000
Total common shareholders' equity	1,236,802,000	1,076,468,000
TOTAL LIABILITIES AND EQUITY	$ 7,032,943,000	$ 6,181,523,000