Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Revenues	$ 359,446	$ 296,007	$ 1,200,058	$ 1,007,132
Residential Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	97,574	97,883	313,302	306,093
Commercial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	95,750	92,148	272,518	262,138
Industrial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	30,090	28,843	82,235	80,983
Public Street and Highway Lighting Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	1,874	1,942	5,769	5,782
Retail Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	225,288	220,816	673,824	654,996
Transmission Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	9,662	7,372	22,764	15,668
Other Electric Revenues from Contracts With Customers [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	11,457	11,610	27,628	24,282
Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	246,407	239,798	724,216	694,946
Avista Utilities [Member]
Disaggregation of Revenue [Line Items]
Revenues	349,655	286,752	1,167,042	974,172
Avista Utilities [Member] | Residential Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	94,451	94,803	299,562	292,714
Avista Utilities [Member] | Commercial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	89,411	86,228	253,694	243,370
Avista Utilities [Member] | Industrial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	30,090	28,843	82,235	80,983
Avista Utilities [Member] | Public Street and Highway Lighting Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	1,810	1,877	5,586	5,598
Avista Utilities [Member] | Retail Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	215,762	211,751	641,077	622,665
Avista Utilities [Member] | Transmission Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	9,662	7,372	22,764	15,668
Avista Utilities [Member] | Other Electric Revenues from Contracts With Customers [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	11,457	11,610	27,628	24,282
Avista Utilities [Member] | Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	236,881	230,733	691,469	662,615
Avista Utilities [Member] | Residential Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	22,960	21,197	174,655	142,401
Avista Utilities [Member] | Commercial Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	11,978	10,055	86,335	65,428
Avista Utilities [Member] | Industrial and Interruptible Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	1,930	1,477	7,238	5,520
Avista Utilities [Member] | Retail Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	36,868	32,729	268,228	213,349
Avista Utilities [Member] | Transportation Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	1,832	1,921	6,331	6,177
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	4,219	3,937
Avista Utilities [Member] | Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	40,107	36,056	278,778	223,463
Avista Utilities [Member] | Revenue from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues	276,988	266,789	970,247	886,078
Avista Utilities [Member] | Derivative revenues
Disaggregation of Revenue [Line Items]
Revenues	76,248	28,087	218,024	91,151
Avista Utilities [Member] | Alternative Revenue Programs [Member]
Disaggregation of Revenue [Line Items]
Revenues	(5,850)	(10,499)	(28,420)	(13,069)
Avista Utilities [Member] | Deferrals and Amortizations for Rate Refunds to Customers
Disaggregation of Revenue [Line Items]
Revenues	(156)	(156)	(25)	2,664
Avista Utilities [Member] | Other Utility Revenues
Disaggregation of Revenue [Line Items]
Revenues	2,113	2,531	7,166	7,348
Alaska Electric Light & Power [Member]
Disaggregation of Revenue [Line Items]
Revenues	9,637	9,147	32,597	32,515
Alaska Electric Light & Power [Member] | Residential Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	3,123	3,080	13,740	13,379
Alaska Electric Light & Power [Member] | Commercial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	6,339	5,920	18,824	18,768
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	64	65	183	184
Alaska Electric Light & Power [Member] | Retail Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	9,526	9,065	32,747	32,331
Alaska Electric Light & Power [Member] | Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	9,526	9,065	32,747	32,331
Alaska Electric Light & Power [Member] | Revenue from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues	9,526	9,065	32,747	32,331
Alaska Electric Light & Power [Member] | Deferrals and Amortizations for Rate Refunds to Customers
Disaggregation of Revenue [Line Items]
Revenues	(49)	(48)	(614)	(143)
Alaska Electric Light & Power [Member] | Other Utility Revenues
Disaggregation of Revenue [Line Items]
Revenues	160	130	464	327
Corporate and Other [Member] | Other Non-utility Revenues
Disaggregation of Revenue [Line Items]
Revenues	$ 154	$ 108	$ 419	$ 445