INCOME TAXES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Current Federal Tax Expense (Benefit)	$ 16,551	$ 61,745	$ (1,568)
Current State and Local Tax Expense (Benefit)	(829)	6,815	(1,565)
Income Tax Expense (Benefit)	15,722	68,560	(3,133)
Deferred Federal Income Tax Expense (Benefit)	21,905	(22,234)	37,810
Deferred State and Local Income Tax Expense (Benefit)	2,868	200	5,639
Deferred Income Taxes and Tax Credits	24,773	(22,034)	43,449
Income Tax Expense (Benefit)	40,495	46,526	40,316
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	$ 271,727	$ 268,268	$ 246,750
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	21.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	$ 57,063	$ 56,335	$ 51,817
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	3,834	7,016	4,074
Amortization of EDIT Regulatory Liability	(20,565)	(17,986)	(17,289)
Amortization of EDIT Regulatory Liability - State Tax	(1,795)	0	0
Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-Based Payment Arrangement, Amount	418	350	(469)
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	1,540	811	$ 2,183
Reduction in income tax expense for the amortization of the regulatory liability associated with excess ADIT that was returned to customers	22,400	18,000
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits	0	4,256
Deferred Tax Assets, Regulatory adjustments	107,948	114,551
Deferred Tax Assets, Operating Loss Carryforwards	93,255	161,320
Deferred Tax Assets, Leasing Arrangements	4,500	9,158
Deferred Tax Assets, Regulatory Assets and Liabilities	5,232	3,384
Deferred Tax Assets, Other	0	3,014
Deferred Tax Assets, Gross	210,935	295,683
Deferred Tax Liabilities, Property, Plant and Equipment	822,619	792,570
Deferred Tax Liabilities, Winter weather events	56,914	121,347
Deferred Tax Liabilities, Net	70,384	71,180
Deferred Tax Liabilities, Tax Deferred Expense, Compensation and Benefits	205	0
Deferred Tax Liabilities, Leasing Arrangements	4,662	9,042
Deferred Tax Liabilities, Other	8,219	0
Deferred Tax Liabilities, Gross	963,003	994,139
Deferred income taxes	752,068	698,456
Deferred Tax Liabilities, Regulatory Assets and Liabilities - Winter Storm Uri	(64,400)	(299,700)
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	93,255	$ 161,320
Domestic Tax Authority
Income Tax Disclosure [Abstract]
Deferred Tax Assets, Operating Loss Carryforwards	87,600
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	87,600
State and Local Jurisdiction
Income Tax Disclosure [Abstract]
Deferred Tax Assets, Operating Loss Carryforwards	5,700
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	$ 5,700