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Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2023 | Sep. 30, 2022
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | $ 379,626 | $ 359,446 | $ 1,234,194 | $ 1,200,058
Alternative revenue programs | 3,578 | (5,850) | (9,947) | (28,420)
Total utility revenues | 379,524 | 359,292 | 1,233,827 | 1,199,639
Unregulated Operating Revenue | 102 | 154 | 367 | 419
Residential Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 99,067 | 97,574 | 319,688 | 313,302
Commercial Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 96,219 | 95,750 | 272,601 | 272,518
Industrial Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 29,584 | 30,090 | 82,707 | 82,235
Public Street and Highway Lighting Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 2,072 | 1,874 | 6,132 | 5,769
Retail Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 226,942 | 225,288 | 681,128 | 673,824
Transmission Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 7,721 | 9,662 | 24,143 | 22,764
Other Electric Revenues from Contracts With Customers [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 9,353 | 11,457 | 33,580 | 27,628
Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 244,016 | 246,407 | 738,851 | 724,216
Avista Utilities [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Derivative revenues | 77,562 | 76,248 | 141,080 | 218,024
Alternative revenue programs | 3,578 | (5,850) | (9,947) | (28,420)
Deferrals and amortizations for rate refunds to customers | 124 | 156 | 769 | 25
Other utility revenues | 2,588 | 2,113 | 7,792 | 7,166
Total utility revenues | 369,673 | 349,655 | 1,198,419 | 1,167,042
Revenue from contract with customer including assessed tax | 285,821 | 276,988 | 1,058,725 | 970,247
Avista Utilities [Member] | Residential Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 95,881 | 94,451 | 305,203 | 299,562
Avista Utilities [Member] | Commercial Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 89,772 | 89,411 | 252,344 | 253,694
Avista Utilities [Member] | Industrial Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 29,584 | 30,090 | 82,707 | 82,235
Avista Utilities [Member] | Public Street and Highway Lighting Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 2,005 | 1,810 | 5,940 | 5,586
Avista Utilities [Member] | Retail Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 217,242 | 215,762 | 646,194 | 641,077
Avista Utilities [Member] | Transmission Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 7,721 | 9,662 | 24,143 | 22,764
Avista Utilities [Member] | Other Electric Revenues from Contracts With Customers [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 9,353 | 11,457 | 33,580 | 27,628
Avista Utilities [Member] | Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 234,316 | 236,881 | 703,917 | 691,469
Avista Utilities [Member] | Residential Natural Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 29,372 | 22,960 | 218,212 | 174,655
Avista Utilities [Member] | Commercial Natural Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 15,381 | 11,978 | 113,183 | 86,335
Avista Utilities [Member] | Industrial and Interruptible Natural Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 3,480 | 1,930 | 13,136 | 7,238
Avista Utilities [Member] | Retail Natural Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 48,233 | 36,868 | 344,531 | 268,228
Avista Utilities [Member] | Transportation Natural Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 1,866 | 1,832 | 6,058 | 6,331
Avista Utilities [Member] | Other Natural Gas Revenues from Contracts With Customers [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 1,406 | 1,407 | 4,219 | 4,219
Avista Utilities [Member] | Natural Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer including assessed tax | 51,505 | 40,107 | 354,808 | 278,778
Alaska Electric Light & Power [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 9,700 | 9,526 | 34,934 | 32,747
Deferrals and amortizations for rate refunds to customers |  | (49) |  | (614)
Other utility revenues | 151 | 160 | 474 | 464
Total utility revenues | 9,851 | 9,637 | 35,408 | 32,597
Alaska Electric Light & Power [Member] | Residential Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 3,186 | 3,123 | 14,485 | 13,740
Alaska Electric Light & Power [Member] | Commercial Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 6,447 | 6,339 | 20,257 | 18,824
Alaska Electric Light & Power [Member] | Public Street and Highway Lighting Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 67 | 64 | 192 | 183
Alaska Electric Light & Power [Member] | Retail Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 9,700 | 9,526 | 34,934 | 32,747
Alaska Electric Light & Power [Member] | Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 9,700 | 9,526 | 34,934 | 32,747
Corporate and Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Unregulated Operating Revenue | $ 102 | $ 154 | $ 367 | $ 419

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