Business Segment Information (Summary Of Company's Reporting Segments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
REVENUE	$ 1,649,917	$ 1,791,711	$ 1,426,132
Depreciation and amortization	287,863	266,504	256,085
Interest Expense	142,926	131,232	125,626
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	71,742	118,485	148,123
Property, Plant and Equipment, Additions	902,705	496,510	291,546
Tax benefit	14,715	21,859	28,941
Net income	57,027	96,626	119,182
TOTAL ASSETS	6,181,523	5,589,214	5,239,767
Accruals for capital expenditures	124,626	66,949	81,325
Financed Capital Expenditures	0	0	36
Electric [Member]
Segment Reporting Information [Line Items]
REVENUE	1,649,917	1,791,711	1,426,132
Depreciation and amortization	287,863	266,504	256,085
Interest Expense	99,051	87,428	84,256
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	115,763	162,862	189,548
Property, Plant and Equipment, Additions		496,510	291,546
TOTAL ASSETS	6,129,581	5,559,977	5,222,987
Other Segments [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	0	0	0
Interest Expense	43,875	43,804	41,370
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(44,021)	(44,377)	(41,425)
Property, Plant and Equipment, Additions	0	0	0
TOTAL ASSETS	$ 51,942	$ 29,237	$ 16,780