Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Income Statement [Abstract]
Operating revenues	$ 351,186	$ 344,471	$ 1,026,019	$ 932,746
Operating expenses:
Purchased natural gas sold	96,057	94,591	413,214	353,192
Electric fuel and purchased power	34,891	36,692	78,639	76,415
Operation and maintenance	112,887	99,955	223,934	207,570
Depreciation and amortization	51,853	49,690	103,114	99,456
Taxes, other than income	25,166	23,969	63,923	59,883
Total operating expenses	320,854	304,897	882,824	796,516
Operating income	30,332	39,574	143,195	136,230
Other income	9,945	10,363	14,942	22,273
Interest expense	25,445	26,500	52,267	53,012
Income before income taxes	14,832	23,437	105,870	105,491
Income taxes	655	3,195	9,226	10,514
Income from continuing operations	14,177	20,242	96,644	94,977
Discontinued operations, net of tax	(397)	40,194	(899)	66,357
Net income	$ 13,780	$ 60,436	$ 95,745	$ 161,334
Earnings per share - basic:
Income from continuing operations (in usd per share)	$ 0.07	$ 0.10	$ 0.47	$ 0.47
Discontinued operations, net of tax (in usd per share)	0	0.20	0	0.32
Earnings per share - basic (in usd per share)	0.07	0.30	0.47	0.79
Earnings per share - diluted:
Income from continuing operations (in usd per share)	0.07	0.10	0.47	0.47
Discontinued operations, net of tax (in usd per share)	0	0.20	0	0.32
Earnings per share - diluted (in usd per share)	$ 0.07	$ 0.30	$ 0.47	$ 0.79
Weighted average common shares outstanding - basic (in shares)	204,331	203,888	204,237	203,834
Weighted average common shares outstanding - diluted (in shares)	205,211	204,582	205,086	204,364