Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 379,937	$ 378,566	$ 854,568	$ 840,612
Residential Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	90,917	88,264	220,621	215,728
Commercial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	87,890	86,764	176,382	176,768
Industrial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	27,956	27,253	53,123	52,145
Public Street and Highway Lighting Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	2,041	1,971	4,060	3,895
Retail Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	208,804	204,252	454,186	448,536
Transmission Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	8,475	8,417	16,422	13,102
Other Electric Revenues from Contracts With Customers [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	6,934	7,409	24,227	16,171
Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	224,213	220,078	494,835	477,809
Avista Utilities [Member]
Disaggregation of Revenue [Line Items]
Revenues	368,604	368,515	828,746	817,387
Avista Utilities [Member] \| Residential Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	86,499	84,108	209,322	205,111
Avista Utilities [Member] \| Commercial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	81,346	80,713	162,572	164,283
Avista Utilities [Member] \| Industrial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	27,956	27,253	53,123	52,145
Avista Utilities [Member] \| Public Street and Highway Lighting Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	1,980	1,912	3,935	3,776
Avista Utilities [Member] \| Retail Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	197,781	193,986	428,952	425,315
Avista Utilities [Member] \| Transmission Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	8,475	8,417	16,422	13,102
Avista Utilities [Member] \| Other Electric Revenues from Contracts With Customers [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	6,934	7,409	24,227	16,171
Avista Utilities [Member] \| Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	213,190	209,812	469,601	454,588
Avista Utilities [Member] \| Residential Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	48,004	48,480	188,840	151,695
Avista Utilities [Member] \| Commercial Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	25,477	23,736	97,802	74,357
Avista Utilities [Member] \| Industrial and Interruptible Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	4,128	2,346	9,656	5,308
Avista Utilities [Member] \| Retail Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	77,609	74,562	296,298	231,360
Avista Utilities [Member] \| Transportation Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	1,923	2,142	4,192	4,499
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	1,407	1,406	2,813	2,812
Avista Utilities [Member] \| Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	80,939	78,110	303,303	238,671
Avista Utilities [Member] \| Revenue from Contracts with Customers [Member]
Disaggregation of Revenue [Line Items]
Revenues	294,129	287,922	772,904	693,259
Avista Utilities [Member] \| Derivative revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	66,580	84,403	63,518	141,776
Avista Utilities [Member] \| Alternative Revenue Programs [Member]
Disaggregation of Revenue [Line Items]
Revenues	5,513	(5,793)	(13,525)	(22,570)
Avista Utilities [Member] \| Deferrals and Amortizations for Rate Refunds to Customers [Member]
Disaggregation of Revenue [Line Items]
Revenues	228	(500)	645	(131)
Avista Utilities [Member] \| Other Utility Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	2,154	2,483	5,204	5,053
Alaska Electric Light & Power [Member]
Disaggregation of Revenue [Line Items]
Revenues	11,194	9,906	25,557	22,960
Alaska Electric Light & Power [Member] \| Residential Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	4,418	4,156	11,299	10,617
Alaska Electric Light & Power [Member] \| Commercial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	6,544	6,051	13,810	12,485
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	61	59	125	119
Alaska Electric Light & Power [Member] \| Retail Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	11,023	10,266	25,234	23,221
Alaska Electric Light & Power [Member] \| Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	11,023	10,266	25,234	23,221
Alaska Electric Light & Power [Member] \| Revenue from Contracts with Customers [Member]
Disaggregation of Revenue [Line Items]
Revenues	11,023	10,266	25,234	23,221
Alaska Electric Light & Power [Member] \| Deferrals and Amortizations for Rate Refunds to Customers [Member]
Disaggregation of Revenue [Line Items]
Revenues		(517)		(565)
Alaska Electric Light & Power [Member] \| Other Utility Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	171	157	323	304
Corporate and Other [Member] \| Other Utility Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 139	$ 145	$ 265	$ 265