CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Utility revenues:
Utility revenues, exclusive of alternative revenue programs	$ 276,351	$ 276,683	$ 944,146	$ 958,750
Alternative revenue programs	(3,972)	6,038	(4,023)	11,105
Total utility revenues	272,379	282,721	940,123	969,855
Non-utility revenues	267	1,049	1,345	11,208
Total operating revenues	272,646	283,770	941,468	981,063
Utility operating expenses:
Resource costs	78,785	98,324	276,297	324,110
Other operating expenses	85,551	80,112	266,251	251,810
Merger transaction costs				19,675
Depreciation and amortization	53,953	50,052	169,282	154,445
Taxes other than income taxes	24,016	23,455	79,736	78,306
Non-utility operating expenses:
Other operating expenses	1,697	1,450	3,716	15,137
Depreciation and amortization	146	134	569	498
Total operating expenses	244,148	253,527	795,851	843,981
Income from operations	28,498	30,243	145,617	137,082
Interest expense	25,812	25,859	77,784	77,021
Interest expense to affiliated trusts	128	334	606	1,042
Capitalized interest	(1,009)	(1,089)	(2,979)	(3,118)
Merger termination fee				(103,000)
Other expense (income)-net	(2,168)	180	(2,019)	(8,995)
Income before income taxes	5,735	4,959	72,225	174,132
Income tax expense (benefit)	859	(131)	1,472	28,145
Net income	4,876	5,090	70,753	145,987
Net loss attributable to noncontrolling interests				(216)
Net income attributable to Avista Corp. shareholders	$ 4,876	$ 5,090	$ 70,753	$ 146,203
Weighted-average common shares outstanding (thousands), basic	68,194	66,265	67,638	65,964
Weighted-average common shares outstanding (thousands), diluted	68,337	66,351	67,769	66,050
Earnings per common share attributable to Avista Corp. shareholders:
Basic	$ 0.07	$ 0.08	$ 1.05	$ 2.22
Diluted	$ 0.07	$ 0.08	$ 1.04	$ 2.21