| Cover | 12 Months Ended |
| Dec. 31, 2022 | |
| Document Information [Line Items] | |
| Document Type | DEF 14A |
| Amendment Flag | false |
| Entity Information [Line Items] | |
| Entity Registrant Name | AVISTA CORPORATION |
| Entity Central Index Key | 0000104918 |
| Pay vs Performance Disclosure | 12 Months Ended | ||
| Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | |
| Pay vs Performance Disclosure [Table] | |||
| Pay vs Performance [Table Text Block] | Pay vs. Performance (“PvP”) Tabular Disclosure — 2022 As required by Section 953(a) of the Dodd-Frank Wall Street Reform and Consumer Protection Act, and Item 402(v) of Regulation S-K, pay-for-performance Pay Performance CEO Average of Other NEOs Value of $100 Initial Investment Year (1) SCT Total Compensation (2) SCT Total Compensation (2) Cumulative Peer Group (3) Net Income EPS 2022 $ 4,745,379 $ 5,290,632 $ 1,318,402 $ 1,605,440 $ 104 $ 103 $ 155.2 $ 2.12 2021 $ 4,577,539 $ 3,485,983 $ 1,257,052 $ 1,082,031 $ 96 $ 103 $ 147.3 $ 2.10 2020 $ 5,004,033 $ 2,234,759 $ 1,173,361 $ 241,559 $ 87 $ 86 $ 129.5 $ 1.90 1. The CEO in all three reporting years is Dennis Vermillion. The other NEOs in the 2022 and 2021 reporting years are: Mark Thies, Jason Thackston, Heather Rosentrater, and Kevin Christie. The other NEOs in the 2020 reporting year are Mark Thies, Jason Thackston, Marian Durkin (ret.), Kevin Christie, and Heather Rosentrater. 2. Amounts reported in this column are based upon total compensation reported for our CEO and our other NEOs in the Summary Compensation Table for the indicated reporting years and adjusted as shown in the table below. Fair value of equity awards was computed in accordance with the Company’s methodology used for financial reporting purposes. 2020 2021 2022 CEO Other NEOs CEO Other NEOs CEO Other NEOs Summary Compensation Table Reported Compensation $ 5,004,033 $ 1,173,361 $ 4,577,539 $ 1,257,052 $ 4,745,379 $ 1,318,402 Deduct: $ (2,290,317 ) $ (335,308 ) $ (905,751 ) $ (170,893 ) $ — $ — Add $ 985,475 $ 73,716 $ 6,658 $ 118,549 $ 3,813 $ 115,378 Deduct: $ (1,778,775 ) $ (432,640 ) $ (1,986,445 ) $ (443,078 ) $ (2,923,157 ) $ (642,502 ) Deduct $ — $ (10,089 ) $ — $ — $ — $ — Add: $ 798,823 $ 154,306 $ 1,865,542 $ 416,058 $ 2,626,495 $ 577,278 Add $ (249,034 ) $ (176,959 ) $ (192,645 ) $ (63,103 ) $ 268,274 $ 61,234 Add $ 109,542 $ 23,708 $ 179,733 $ 40,100 $ 217,488 $ 63,451 Add: $ (410,431 ) $ (250,148 ) $ (197,784 ) $ (108,165 ) $ 119,893 $ 60,392 Add $ 65,443 $ 21,612 $ 139,135 $ 35,511 $ 232,446 $ 51,807 Total Compensation Actually Paid $ 2,234,759 $ 241,559 $ 3,485,983 $ 1,082,031 $ 5,290,632 $ 1,605,440 3. Amounts reported in this column represent returns on an initial $100 investment in the S&P 400 Utilities Index, which we chose as peer group for purposes of the PvP table. | ||
| Company Selected Measure Name | EPS | ||
| Named Executive Officers, Footnote [Text Block] | 1. The CEO in all three reporting years is Dennis Vermillion. The other NEOs in the 2022 and 2021 reporting years are: Mark Thies, Jason Thackston, Heather Rosentrater, and Kevin Christie. The other NEOs in the 2020 reporting year are Mark Thies, Jason Thackston, Marian Durkin (ret.), Kevin Christie, and Heather Rosentrater. | ||
| Peer Group Issuers, Footnote [Text Block] | Amounts reported in this column represent returns on an initial $100 investment in the S&P 400 Utilities Index, which we chose as peer group for purposes of the PvP table. | ||
| PEO Total Compensation Amount | $ 4,745,379 | $ 4,577,539 | $ 5,004,033 |
| PEO Actually Paid Compensation Amount | $ 5,290,632 | 3,485,983 | 2,234,759 |
| Adjustment To PEO Compensation, Footnote [Text Block] | 2. Amounts reported in this column are based upon total compensation reported for our CEO and our other NEOs in the Summary Compensation Table for the indicated reporting years and adjusted as shown in the table below. Fair value of equity awards was computed in accordance with the Company’s methodology used for financial reporting purposes. 2020 2021 2022 CEO Other NEOs CEO Other NEOs CEO Other NEOs Summary Compensation Table Reported Compensation $ 5,004,033 $ 1,173,361 $ 4,577,539 $ 1,257,052 $ 4,745,379 $ 1,318,402 Deduct: $ (2,290,317 ) $ (335,308 ) $ (905,751 ) $ (170,893 ) $ — $ — Add $ 985,475 $ 73,716 $ 6,658 $ 118,549 $ 3,813 $ 115,378 Deduct: $ (1,778,775 ) $ (432,640 ) $ (1,986,445 ) $ (443,078 ) $ (2,923,157 ) $ (642,502 ) Deduct $ — $ (10,089 ) $ — $ — $ — $ — Add: $ 798,823 $ 154,306 $ 1,865,542 $ 416,058 $ 2,626,495 $ 577,278 Add $ (249,034 ) $ (176,959 ) $ (192,645 ) $ (63,103 ) $ 268,274 $ 61,234 Add $ 109,542 $ 23,708 $ 179,733 $ 40,100 $ 217,488 $ 63,451 Add: $ (410,431 ) $ (250,148 ) $ (197,784 ) $ (108,165 ) $ 119,893 $ 60,392 Add $ 65,443 $ 21,612 $ 139,135 $ 35,511 $ 232,446 $ 51,807 Total Compensation Actually Paid $ 2,234,759 $ 241,559 $ 3,485,983 $ 1,082,031 $ 5,290,632 $ 1,605,440 | ||
| Non-PEO NEO Average Total Compensation Amount | $ 1,318,402 | 1,257,052 | 1,173,361 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 1,605,440 | 1,082,031 | 241,559 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | 2. Amounts reported in this column are based upon total compensation reported for our CEO and our other NEOs in the Summary Compensation Table for the indicated reporting years and adjusted as shown in the table below. Fair value of equity awards was computed in accordance with the Company’s methodology used for financial reporting purposes. 2020 2021 2022 CEO Other NEOs CEO Other NEOs CEO Other NEOs Summary Compensation Table Reported Compensation $ 5,004,033 $ 1,173,361 $ 4,577,539 $ 1,257,052 $ 4,745,379 $ 1,318,402 Deduct: $ (2,290,317 ) $ (335,308 ) $ (905,751 ) $ (170,893 ) $ — $ — Add $ 985,475 $ 73,716 $ 6,658 $ 118,549 $ 3,813 $ 115,378 Deduct: $ (1,778,775 ) $ (432,640 ) $ (1,986,445 ) $ (443,078 ) $ (2,923,157 ) $ (642,502 ) Deduct $ — $ (10,089 ) $ — $ — $ — $ — Add: $ 798,823 $ 154,306 $ 1,865,542 $ 416,058 $ 2,626,495 $ 577,278 Add $ (249,034 ) $ (176,959 ) $ (192,645 ) $ (63,103 ) $ 268,274 $ 61,234 Add $ 109,542 $ 23,708 $ 179,733 $ 40,100 $ 217,488 $ 63,451 Add: $ (410,431 ) $ (250,148 ) $ (197,784 ) $ (108,165 ) $ 119,893 $ 60,392 Add $ 65,443 $ 21,612 $ 139,135 $ 35,511 $ 232,446 $ 51,807 Total Compensation Actually Paid $ 2,234,759 $ 241,559 $ 3,485,983 $ 1,082,031 $ 5,290,632 $ 1,605,440 | ||
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | |||
| Compensation Actually Paid vs. Net Income [Text Block] | |||
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | |||
| Total Shareholder Return Vs Peer Group [Text Block] | |||
| Tabular List [Table Text Block] | Most Important Measures Linking Avista NEO Pay to Performance — 2022 The following are the most important financial and non-financial • EPS • 3-Year • Net Income | ||
| Total Shareholder Return Amount | $ 104 | 96 | 87 |
| Peer Group Total Shareholder Return Amount | 103 | 103 | 86 |
| Net Income (Loss) | $ 155,200,000 | $ 147,300,000 | $ 129,500,000 |
| Company Selected Measure Amount | 2.12 | 2.1 | 1.9 |
| PEO Name | Dennis Vermillion | ||
| Measure [Axis]: 1 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | EPS | ||
| Measure [Axis]: 2 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | 3-Year Relative TSR | ||
| Measure [Axis]: 3 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Net Income | ||
| PEO [Member] | SCT Reported Change in Pension Value [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ 0 | $ (905,751) | $ (2,290,317) |
| PEO [Member] | CAP Pension Value [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 3,813 | 6,658 | 985,475 |
| PEO [Member] | Grant Date Fair Values of Equity Awards Reported in Stock Awards Column of the SCT [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (2,923,157) | (1,986,445) | (1,778,775) |
| PEO [Member] | For Any Awards Granted in Any Prior FY Forfeited During the Covered FY, the Fair Value at the End of the Prior FY [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Fair Values as of the End of the Covered FY of All Equity Awards Granted During the Covered FY Outstanding and Unvested [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 2,626,495 | 1,865,542 | 798,823 |
| PEO [Member] | The Change in Fair Value as of the End of the Covered FY of Any Equity Awards Granted in Any Prior FY Outstanding and Unvested [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 268,274 | (192,645) | (249,034) |
| PEO [Member] | For Awards Granted and Vested in the Same FY, the Fair Value as of the Vesting Date [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 217,488 | 179,733 | 109,542 |
| PEO [Member] | The Change in Fair Value as of the Vesting Date of Any Awards Granted in Any Prior FY for Which All Applicable Vesting Conditions [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 119,893 | (197,784) | (410,431) |
| PEO [Member] | The Dollar Value of Any Dividends or Other Earnings Paid on Stock or Option Awards in the Covered FY Prior to the Vesting Date [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 232,446 | 139,135 | 65,443 |
| Non-PEO NEO [Member] | SCT Reported Change in Pension Value [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | (170,893) | (335,308) |
| Non-PEO NEO [Member] | CAP Pension Value [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 115,378 | 118,549 | 73,716 |
| Non-PEO NEO [Member] | Grant Date Fair Values of Equity Awards Reported in Stock Awards Column of the SCT [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (642,502) | (443,078) | (432,640) |
| Non-PEO NEO [Member] | For Any Awards Granted in Any Prior FY Forfeited During the Covered FY, the Fair Value at the End of the Prior FY [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | (10,089) |
| Non-PEO NEO [Member] | Fair Values as of the End of the Covered FY of All Equity Awards Granted During the Covered FY Outstanding and Unvested [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 577,278 | 416,058 | 154,306 |
| Non-PEO NEO [Member] | The Change in Fair Value as of the End of the Covered FY of Any Equity Awards Granted in Any Prior FY Outstanding and Unvested [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 61,234 | (63,103) | (176,959) |
| Non-PEO NEO [Member] | For Awards Granted and Vested in the Same FY, the Fair Value as of the Vesting Date [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 63,451 | 40,100 | 23,708 |
| Non-PEO NEO [Member] | The Change in Fair Value as of the Vesting Date of Any Awards Granted in Any Prior FY for Which All Applicable Vesting Conditions [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 60,392 | (108,165) | (250,148) |
| Non-PEO NEO [Member] | The Dollar Value of Any Dividends or Other Earnings Paid on Stock or Option Awards in the Covered FY Prior to the Vesting Date [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ 51,807 | $ 35,511 | $ 21,612 |
