Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenue:
Revenue	$ 921,159	$ 823,570
Operating expenses:
Fuel, purchased power and cost of natural gas sold	526,267	436,926
Operations and maintenance	140,988	136,132
Depreciation, depletion and amortization	61,643	60,463
Taxes - property and production	17,378	16,696
Total operating expenses	746,276	650,217
Operating income	174,883	173,353
Other income (expense):
Interest expense incurred net of amounts capitalized (including amortization of debt issuance costs, premiums and discounts)	(44,065)	(38,821)
Interest income	561	276
Other income, net	674	704
Total other income (expense)	(42,830)	(37,841)
Income before income taxes	132,053	135,512
Income tax (expense)	(14,673)	(14,488)
Net income	117,380	121,024
Net income attributable to non-controlling interest	(3,296)	(3,498)
Net income available for common stock	$ 114,084	$ 117,526
Earnings per share of common stock:
Earnings per share, Basic (usd per share)	$ 1.73	$ 1.82
Earnings per share, Diluted (usd per share)	$ 1.73	$ 1.82
Weighted average common shares outstanding:
Basic (in shares)	66,036	64,565
Diluted (in shares)	66,132	64,721