Investments (Details-3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Equity method investment summarized assets [Abstract]
Total Current Assets	$ 243,480	$ 199,371
Total Assets	2,517,600	2,371,906	$ 2,253,651
Equity method investment summarized liabilities and equity [Abstract]
Total Current Liabilities	225,062	117,847
Total Other Credits	625,618	612,380
Total Liabilities and Capitalization	2,517,600	2,371,906
ATC [Member]
Equity method investment summarized income statement [Abstract]
Operating revenues	751,158	754,838	758,117
Operating expenses	(381,528)	(376,153)	(372,463)
Other income, net	1,171	1,144	1,922
Interest expense, net	(124,091)	(115,089)	(112,818)
Earnings before members' income taxes	246,710	264,740	$ 274,758
Equity method investment summarized assets [Abstract]
Total Current Assets	89,606	89,747
Total Noncurrent Assets	5,997,780	5,628,127
Total Assets	6,087,386	5,717,874
Equity method investment summarized liabilities and equity [Abstract]
Total Current Liabilities	511,945	436,918
Long-term debt	2,612,980	2,513,009
Total Other Credits	485,795	421,997
Total Equity	2,476,666	2,345,950
Total Liabilities and Capitalization	$ 6,087,386	$ 5,717,874