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Long-Term Debt to Affiliated Trusts - Additional Information (Details) - USD ($)
$ in Millions
1 Months Ended 6 Months Ended 12 Months Ended
Jul. 31, 2023
Jun. 30, 2023
Dec. 31, 2000
Debt Instrument [Line Items]      
Payments for repurchase of trust preferred securities     $ 10.0
1997 Floating Rate Junior Subordinated Deferrable Interest Debentures, Series B [Member] | Avista Capital II [Member]      
Debt Instrument [Line Items]      
Junior subordinated debenture issuance date   1997  
Principal amount   $ 51.5  
Avista Corp [Member]      
Debt Instrument [Line Items]      
Noncontrolling interest, ownership percentage by parent   100.00%  
Trust Preferred Securities Subject to Mandatory Redemption [Member] | 1997 Floating Rate Junior Subordinated Deferrable Interest Debentures, Series B [Member] | Avista Capital II [Member]      
Debt Instrument [Line Items]      
Principal amount   $ 50.0  
Debt instrument, description of variable rate basis   LIBOR  
Debt instrument, basis spread on variable rate   0.875%  
Trust Preferred Securities Subject to Mandatory Redemption [Member] | 1997 Floating Rate Junior Subordinated Deferrable Interest Debentures, Series B [Member] | SOFR [Member] | Avista Capital II [Member] | Forecast [Member]      
Debt Instrument [Line Items]      
Debt instrument, basis spread on variable rate 1.137%    
Debt instrument basis tenor spread adjustment rate 0.26%    
Common Trust Securities [Member] | 1997 Floating Rate Junior Subordinated Deferrable Interest Debentures, Series B [Member] | Avista Capital II [Member]      
Debt Instrument [Line Items]      
Principal amount   $ 1.5