Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Operating revenues:
Operating revenues:	$ 1,091,126	$ 1,009,749	$ 2,521,224	$ 2,116,864
Operating expenses:
Operation and maintenance:	769,593	709,517	1,566,138	1,310,073
Purchased natural gas sold	115,866	115,312	486,881	382,665
Depreciation, depletion and amortization	53,498	55,006	105,730	106,779
Taxes, other than income	49,706	45,480	117,133	99,057
Electric fuel and purchased power	20,432	21,929	44,789	48,290
Total operating expenses	1,009,095	947,244	2,320,671	1,946,864
Operating income	82,031	62,505	200,553	170,000
Unrealized Gain (Loss) on investment in Knife River	140,020	0	140,020	0
Other income (expense)	9,959	(2,209)	20,333	(3,253)
Interest expense	26,459	19,187	50,412	38,079
Income before income taxes	205,551	41,109	310,494	128,668
Income taxes	57,918	5,347	78,986	24,140
Income from continuing operations	147,633	35,762	231,508	104,528
Discontinued operations, net of tax	(16,941)	34,905	(62,464)	(2,098)
Net income	$ 130,692	$ 70,667	$ 169,044	$ 102,430
Earnings per share - basic:
Income from continuing operations	$ 0.72	$ 0.18	$ 1.14	$ 0.51
Discontinued operations, net of tax	(0.08)	0.17	(0.31)	(0.01)
Earnings per share - basic	0.64	0.35	0.83	0.50
Earnings per share - diluted:
Income from continuing operations	0.72	0.18	1.14	0.51
Discontinued operations, net of tax	(0.08)	0.17	(0.31)	(0.01)
Earnings per share - diluted	$ 0.64	$ 0.35	$ 0.83	$ 0.50
Weighted average common shares outstanding - basic	203,635	203,351	203,630	203,351
Weighted average common shares outstanding - diluted	203,877	203,401	203,894	203,396
Regulated operation
Operating revenues:
Operating revenues:	$ 340,492	$ 323,616	$ 1,014,423	$ 877,233
Operating expenses:
Operation and maintenance:	95,483	94,422	197,522	192,247
Income from continuing operations	21,832	4,429	86,296	60,047
Nonregulated operation
Operating revenues:
Operating revenues:	750,634	686,133	1,506,801	1,239,631
Operating expenses:
Operation and maintenance:	674,110	615,095	1,368,616	1,117,826
Income from continuing operations	$ 125,801	$ 31,333	$ 145,212	$ 44,481