Unaudited Condensed Consolidated Statements Of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Costs and Expenses	$ 289,303	$ 282,610
REVENUES	362,201	357,382
Cost of Revenue [Abstract]
Fuel Costs	84,731	68,788
Cost of Goods and Services Sold	24,583	35,467
OPERATING EXPENSES:
Utilities Operating Expense, Maintenance and Operations	103,949	105,590
Depreciation and amortization	63,089	60,708
Taxes other than income taxes	12,951	12,057
Operating Income (Loss)	72,898	74,772
Allowance for equity funds used during construction	1,374	857
Interest Expense	30,067	30,081
Other Nonoperating Income (Expense)	4,614	207
Nonoperating Income (Expense)	(24,079)	(29,017)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	48,819	45,755
Income Tax Expense (Benefit)	10,035	9,772
Net income	38,784	35,983
Less: Dividends on preferred stock	803	803
Net Income (Loss) Available to Common Stockholders, Basic	37,981	35,180
OPERATING INCOME	72,898	74,772
OTHER INCOME / (EXPENSE), NET:
Allowance for equity funds used during construction	1,374	857
Interest Expense	(30,067)	(30,081)
Other Nonoperating Income (Expense)	4,614	207
Total other income / (expense), net	(24,079)	(29,017)
EARNINGS FROM OPERATIONS BEFORE INCOME TAX
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	48,819	45,755
Income Tax Expense (Benefit)	10,035	9,772
NET INCOME	38,784	35,983
Less: Dividends on preferred stock	803	803
NET INCOME APPLICABLE TO COMMON STOCK	37,981	35,180
Electricity [Member]
REVENUES	$ 362,201	$ 357,382