CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Utility revenues:
Utility revenues, exclusive of alternative revenue programs	$ 1,742,876	$ 1,445,000	$ 1,324,091
Alternative revenue programs	(33,357)	(6,635)	(3,814)
Total utility revenues	1,709,519	1,438,365	1,320,277
Non-utility revenues	688	571	1,614
Total operating revenues	1,710,207	1,438,936	1,321,891
Utility operating expenses:
Resource costs	735,862	497,123	398,509
Other operating expenses	405,165	366,125	354,614
Depreciation and amortization	253,017	231,915	223,507
Taxes other than income taxes	114,193	109,353	106,501
Non-utility operating expenses:
Other operating expenses	11,603	5,927	5,344
Depreciation and amortization	125	261	716
Total operating expenses	1,519,965	1,210,704	1,089,191
Income from operations	190,242	228,232	232,700
Interest expense	117,634	105,731	104,348
Interest expense to affiliated trusts	1,058	421	713
Capitalized interest	(3,718)	(3,987)	(4,083)
Other income-net	(62,717)	(33,298)	(4,817)
Income before income taxes	137,985	159,365	136,539
Income tax expense (benefit)	(17,191)	12,031	7,051
Net income	$ 155,176	$ 147,334	$ 129,488
Weighted-average common shares outstanding (thousands), basic	72,989	69,951	67,962
Weighted-average common shares outstanding (thousands), diluted	73,093	70,085	68,102
Earnings per common share:
Basic	$ 2.13	$ 2.11	$ 1.91
Diluted	$ 2.12	$ 2.10	$ 1.90