Investments (Details-1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Equity Securities [Abstract]
Equity securities	$ 24,027	$ 22,960
Equity method investments: [Abstract]
Equity method investments	86,498	80,625
Other investments	2,298	2,298
Total investments	112,823	105,883
Proceeds from Sale, Maturity and Collection of Investments [Abstract]
Proceeds from sale of investments	995	924	$ 1,684
Gain (loss) on sale of investments	(899)	1,382	1,543
ATC and ATC Holdco [Member]
Equity method investments: [Abstract]
Equity method investments	86,459	80,586
Other Equity Method Investments [Member]
Equity method investments: [Abstract]
Equity method investments	39	39
MGE [Member]
Equity Securities [Abstract]
Equity securities	60	115
Equity method investments: [Abstract]
Equity method investments	0	0
Other investments	0	0
Total investments	60	115
Proceeds from Sale, Maturity and Collection of Investments [Abstract]
Proceeds from sale of investments	0	0	0
Gain (loss) on sale of investments	0	0	$ 0
MGE [Member] | ATC and ATC Holdco [Member]
Equity method investments: [Abstract]
Equity method investments	0	0
MGE [Member] | Other Equity Method Investments [Member]
Equity method investments: [Abstract]
Equity method investments	$ 0	$ 0