Segment and Related Information (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Total revenues	$ 373,466	$ 356,009	$ 1,513,898	$ 1,422,143	$ 1,477,837
Utilities Operating Expense, Fuel Used			433,816	420,262	492,011
Operating and maintenance			227,836	220,524	221,427
Administrative and general			137,437	117,360	113,776
Property and other taxes			163,853	153,068	192,524
Depreciation and depletion			227,635	210,474	195,020
Operating Income	91,696	103,163	323,321	300,455	263,079
Interest expense			(131,673)	(114,617)	(100,110)
Other income, net			23,024	15,832	19,434
Income tax benefit			9,439	(7,539)	605
Net Income	$ 80,552	$ 83,142	224,111	194,131	183,008
Operating Segments | Electric
Segment Reporting Information [Line Items]
Total revenues			1,200,701	1,068,833	1,106,565
Utilities Operating Expense, Fuel Used			329,578	262,755	324,434
Operating and maintenance			270,145	249,549	250,203
Property and other taxes			126,470	120,289	149,781
Depreciation and depletion			189,987	174,071	162,404
Interest expense			(99,250)	(84,089)	(74,420)
Other income, net			18,082	11,580	12,491
Income tax benefit			(20,892)	(14,196)	798
Net Income			182,461	175,464	158,612
Operating Segments | Gas Domestic Regulated [Member]
Segment Reporting Information [Line Items]
Total revenues			313,197	353,310	371,272
Utilities Operating Expense, Fuel Used			104,238	157,507	167,577
Operating and maintenance			92,211	87,153	84,631
Property and other taxes			37,386	34,323	42,734
Depreciation and depletion			37,648	36,403	32,616
Interest expense			(27,740)	(15,719)	(13,030)
Other income, net			5,803	3,344	6,399
Income tax benefit			7,963	4,627	(3,108)
Net Income			27,740	30,176	33,975
Operating Segments | Regulated Electric and Natural Gas Segments
Segment Reporting Information [Line Items]
Total revenues			1,513,898	1,422,143	1,477,837
Utilities Operating Expense, Fuel Used			433,816	420,262	492,011
Operating and maintenance			362,356	336,702	334,834
Property and other taxes			163,856	154,612	192,515
Depreciation and depletion			227,635	210,474	195,020
Interest expense			(126,990)	(99,808)	(87,450)
Other income, net			23,885	14,924	18,890
Income tax benefit			(12,929)	(9,569)	(2,310)
Net Income			210,201	205,640	192,587
Other Operating Segment [Member] | Operating Segments
Segment Reporting Information [Line Items]
Net Income			$ 13,910	$ (11,509)	$ (9,579)