Business Segment Information (Summary Of Company's Reporting Segments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
REVENUES	$ 1,426,132	$ 1,352,985	$ 1,481,643
Depreciation and amortization	256,085	246,896	240,314
Interest Expense	125,626	129,493	121,771
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	148,123	138,559	167,921
Property, Plant and Equipment, Additions	291,546	235,736	219,242
Tax benefit	28,941	28,592	35,528
Net income	119,182	109,967	132,393
TOTAL ASSETS	5,239,767	4,969,919	4,928,669
Accruals for capital expenditures	81,325	54,360	35,471
Financed Capital Expenditures	0	0	5,600
Electric [Member]
Segment Reporting Information [Line Items]
REVENUES	1,426,132	1,352,985	1,481,643
Depreciation and amortization	256,085	246,896	240,314
Interest Expense	84,256	87,281	89,014
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	189,548	184,174	200,707
Property, Plant and Equipment, Additions		235,736	219,242
TOTAL ASSETS	5,222,987	4,952,408	4,918,408
Other Segments [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	0	0	0
Interest Expense	41,370	42,212	32,757
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(41,425)	(45,615)	(32,786)
Property, Plant and Equipment, Additions	0	0	0
TOTAL ASSETS	$ 16,780	$ 17,511	$ 10,261