CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Utility revenues:
Utility revenues, exclusive of alternative revenue programs	$ 1,445,000	$ 1,324,091	$ 1,323,524
Alternative revenue programs	(6,635)	(3,814)	9,614
Total utility revenues	1,438,365	1,320,277	1,333,138
Non-utility revenues	571	1,614	12,484
Total operating revenues	1,438,936	1,321,891	1,345,622
Utility operating expenses:
Resource costs	497,123	398,509	439,817
Other operating expenses	366,125	354,614	345,212
Merger transaction costs			19,675
Depreciation and amortization	231,915	223,507	205,365
Taxes other than income taxes	109,353	106,501	105,652
Non-utility operating expenses:
Other operating expenses	5,927	5,344	18,883
Depreciation and amortization	261	716	629
Total operating expenses	1,210,704	1,089,191	1,135,233
Income from operations	228,232	232,700	210,389
Interest expense	105,731	104,348	103,012
Interest expense to affiliated trusts	421	713	1,342
Capitalized interest	(3,987)	(4,083)	(4,174)
Merger termination fee			(103,000)
Other income-net	(33,298)	(4,817)	(14,928)
Income before income taxes	159,365	136,539	228,137
Income tax expense	12,031	7,051	31,374
Net income	147,334	129,488	196,763
Net loss attributable to noncontrolling interests			(216)
Net income attributable to Avista Corp. shareholders	$ 147,334	$ 129,488	$ 196,979
Weighted-average common shares outstanding (thousands), basic	69,951	67,962	66,205
Weighted-average common shares outstanding (thousands), diluted	70,085	68,102	66,329
Earnings per common share attributable to Avista Corp. shareholders:
Basic	$ 2.11	$ 1.91	$ 2.98
Diluted	$ 2.10	$ 1.90	$ 2.97