Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Revenues	$ 1,710,207	$ 1,438,936	$ 1,321,891
Residential Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	434,490	413,657	396,403
Commercial and Governmental Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	364,438	352,034	327,726
Industrial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	107,740	106,756	103,103
Public Street and Highway Lighting Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	7,737	7,722	7,555
Retail Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	914,405	880,169	834,787
Transmission Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	32,307	21,005	18,236
Other Electric Revenues from Contracts With Customers [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	49,920	33,870	19,252
Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	996,632	935,044	872,275
Avista Utilities [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,663,815	1,392,999	1,277,468
Avista Utilities [Member] \| Residential Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	414,823	394,717	377,785
Avista Utilities [Member] \| Commercial and Governmental Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	338,656	326,173	303,972
Avista Utilities [Member] \| Industrial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	107,740	106,756	103,103
Avista Utilities [Member] \| Public Street and Highway Lighting Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	7,483	7,472	7,303
Avista Utilities [Member] \| Retail Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	868,702	835,118	792,163
Avista Utilities [Member] \| Transmission Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	32,307	21,005	18,236
Avista Utilities [Member] \| Other Electric Revenues from Contracts With Customers [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	49,920	33,870	19,252
Avista Utilities [Member] \| Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	950,929	889,993	829,651
Avista Utilities [Member] \| Residential Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	284,452	221,405	213,612
Avista Utilities [Member] \| Commercial Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	139,923	100,819	94,937
Avista Utilities [Member] \| Industrial and Interruptible Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	10,471	7,796	7,128
Avista Utilities [Member] \| Retail Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	434,846	330,020	315,677
Avista Utilities [Member] \| Transportation Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	8,627	8,547	7,917
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	5,625	5,344	4,501
Avista Utilities [Member] \| Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	449,098	343,911	328,095
Avista Utilities [Member] \| Revenue from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues	1,400,027	1,233,904	1,157,746
Avista Utilities [Member] \| Derivative revenues
Disaggregation of Revenue [Line Items]
Revenues	286,309	152,590	110,313
Avista Utilities [Member] \| Alternative Revenue Programs [Member]
Disaggregation of Revenue [Line Items]
Revenues	(33,357)	(6,635)	(3,814)
Avista Utilities [Member] \| Deferrals and Amortizations for Rate Refunds to Customers
Disaggregation of Revenue [Line Items]
Revenues	207	2,984	5,335
Avista Utilities [Member] \| Other Utility Revenues
Disaggregation of Revenue [Line Items]
Revenues	10,629	10,156	7,888
Alaska Electric Light & Power [Member]
Disaggregation of Revenue [Line Items]
Revenues	45,704	45,366	42,809
Alaska Electric Light & Power [Member] \| Residential Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	19,667	18,940	18,618
Alaska Electric Light & Power [Member] \| Commercial and Governmental Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	25,782	25,861	23,754
Alaska Electric Light & Power [Member] \| Public Street and Highway Lighting Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	254	250	252
Alaska Electric Light & Power [Member] \| Retail Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	45,703	45,051	42,624
Alaska Electric Light & Power [Member] \| Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	45,703	45,051	42,624
Alaska Electric Light & Power [Member] \| Revenue from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues	45,703	45,051	42,624
Alaska Electric Light & Power [Member] \| Deferrals and Amortizations for Rate Refunds to Customers
Disaggregation of Revenue [Line Items]
Revenues	(614)	(190)	(190)
Alaska Electric Light & Power [Member] \| Other Utility Revenues
Disaggregation of Revenue [Line Items]
Revenues	615	505	375
Corporate and Other [Member]
Disaggregation of Revenue [Line Items]
Revenues	688	571	1,614
Corporate and Other [Member] \| Revenue from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues		2	564
Corporate and Other [Member] \| Other Revenues
Disaggregation of Revenue [Line Items]
Revenues	$ 688	$ 569	$ 1,050