Investment in ATC and ATC Holdco (Details-2) - ATC [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Schedule of Equity Method Investments [Line Items]
Operating revenues	$ 190,999	$ 188,694
Operating expenses	(95,491)	(95,104)
Other income, net	404	378
Interest expense, net	(28,440)	(28,871)
Earnings before members' income taxes	$ 67,472	$ 65,097