XML 148 R106.htm IDEA: XBRL DOCUMENT v2.4.1.9
Long-Term Debt (Schedule Of Long-Term Debt Instruments) (Details) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 1998
Debt Instrument [Line Items]        
Debt instrument, interest rate, stated percentage 1.11%us-gaap_DebtInstrumentInterestRateStatedPercentage 1.11%us-gaap_DebtInstrumentInterestRateStatedPercentage 1.19%us-gaap_DebtInstrumentInterestRateStatedPercentage 8.45%us-gaap_DebtInstrumentInterestRateStatedPercentage
Interest Rate, minimum 1.10%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum 1.11%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum 1.19%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum  
Interest Rate, maximum 1.11%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum 1.19%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum 1.40%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum  
Secured Debt $ 1,511,700us-gaap_SecuredDebt $ 1,376,700us-gaap_SecuredDebt    
Secured and Unsecured Debt 1,526,700ava_SecuredandUnsecuredDebt 1,376,700ava_SecuredandUnsecuredDebt    
Other long-term debt and capital leases 1,492,062us-gaap_LongTermDebtAndCapitalLeaseObligations 1,272,425us-gaap_LongTermDebtAndCapitalLeaseObligations    
Settled interest rate swaps (17,541)ava_SettledInterestRateSwaps [1] (23,560)ava_SettledInterestRateSwaps [1]    
Unamortized debt discount (1,122)us-gaap_DebtInstrumentUnamortizedDiscount (1,287)us-gaap_DebtInstrumentUnamortizedDiscount    
Total 1,582,186ava_LongTermDebtBeforeCurrentPortionAndBondsHeldByCompany 1,356,483ava_LongTermDebtBeforeCurrentPortionAndBondsHeldByCompany    
Pollution Control Bonds (83,700)us-gaap_LongTermPollutionControlBond [2],[3] (83,700)us-gaap_LongTermPollutionControlBond [2],[3]    
Other Long-term Debt and Capital Lease Obligations 74,149ava_OtherLongTermDebtAndCapitalLeaseObligations 4,630ava_OtherLongTermDebtAndCapitalLeaseObligations    
Long-term Debt and Capital Lease Obligations, Current (6,424)us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent (358)us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent    
2018, 7.39% - 7.45% [Member] | Secured Debt [Member]        
Debt Instrument [Line Items]        
Interest Rate, minimum 7.39%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandEighteenSevenPointThreeNinePercentageToSevenPointFourFivePercentageMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		      
Interest Rate, maximum 7.45%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandEighteenSevenPointThreeNinePercentageToSevenPointFourFivePercentageMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		      
2023, 7.18% - 7.54% [Member] | Secured Debt [Member]        
Debt Instrument [Line Items]        
Interest Rate, minimum 7.18%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum
/ us-gaap_DebtInstrumentAxis
= ava_TwoThosuandTwentyThreeSevenPointOneEightPercentageToSevenPointFiveFourPercentageMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		      
Interest Rate, maximum 7.54%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum
/ us-gaap_DebtInstrumentAxis
= ava_TwoThosuandTwentyThreeSevenPointOneEightPercentageToSevenPointFiveFourPercentageMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		      
2032 [Member] | Secured Debt [Member]        
Debt Instrument [Line Items]        
Pollution Control Bonds 66,700us-gaap_LongTermPollutionControlBond
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandThirtyTwoMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		      
2034 [Member] | Secured Debt [Member]        
Debt Instrument [Line Items]        
Pollution Control Bonds 17,000us-gaap_LongTermPollutionControlBond
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandThirtyFourMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		      
Alaska Electric Light & Power [Member] | Two Thousand Forty Four [Member] | First Mortgage [Member]        
Debt Instrument [Line Items]        
Maturity Year 2044 [4]      
Debt instrument, interest rate, stated percentage 4.54%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandFortyFourMember
/ dei_LegalEntityAxis
= ava_AlaskaElectricLightPowerMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 [4]      
Secured Debt 75,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandFortyFourMember
/ dei_LegalEntityAxis
= ava_AlaskaElectricLightPowerMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 [4] 0us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandFortyFourMember
/ dei_LegalEntityAxis
= ava_AlaskaElectricLightPowerMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 [4]    
Avista Corporation [Member]        
Debt Instrument [Line Items]        
Secured Debt 1,436,700us-gaap_SecuredDebt
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember		 1,376,700us-gaap_SecuredDebt
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember		    
Avista Corporation [Member] | Two Thousand Forty Four [Member] | First Mortgage [Member]        
Debt Instrument [Line Items]        
Maturity Year 2044 [2]      
Debt instrument, interest rate, stated percentage 4.11%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandFortyFourMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 [2]      
Secured Debt 60,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandFortyFourMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 [2]      
Avista Corporation [Member] | 2016 | First Mortgage [Member]        
Debt Instrument [Line Items]        
Maturity Year 2016      
Debt instrument, interest rate, stated percentage 0.84%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandSixteenMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		      
Secured Debt 90,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandSixteenMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 90,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandSixteenMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		    
Avista Corporation [Member] | 2018, 5.95% [Member] | First Mortgage [Member]        
Debt Instrument [Line Items]        
Maturity Year 2018      
Debt instrument, interest rate, stated percentage 5.95%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandEighteenFivePointNineFivePercentageMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		      
Secured Debt 250,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandEighteenFivePointNineFivePercentageMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 250,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandEighteenFivePointNineFivePercentageMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		    
Avista Corporation [Member] | 2018, 7.39% - 7.45% [Member] | Secured Debt [Member]        
Debt Instrument [Line Items]        
Maturity Year 2018      
Medium-Term Notes, Noncurrent 22,500us-gaap_MediumtermNotesNoncurrent
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandEighteenSevenPointThreeNinePercentageToSevenPointFourFivePercentageMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		 22,500us-gaap_MediumtermNotesNoncurrent
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandEighteenSevenPointThreeNinePercentageToSevenPointFourFivePercentageMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		    
Avista Corporation [Member] | 2019 [Member] | First Mortgage [Member]        
Debt Instrument [Line Items]        
Maturity Year 2019      
Debt instrument, interest rate, stated percentage 5.45%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandNineteenMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		      
Secured Debt 90,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandNineteenMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 90,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandNineteenMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		    
Avista Corporation [Member] | 2020 [Member] | First Mortgage [Member]        
Debt Instrument [Line Items]        
Maturity Year 2020      
Debt instrument, interest rate, stated percentage 3.89%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandTwentyMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		      
Secured Debt 52,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandTwentyMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 52,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandTwentyMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		    
Avista Corporation [Member] | 2022 [Member] | First Mortgage [Member]        
Debt Instrument [Line Items]        
Maturity Year 2022      
Debt instrument, interest rate, stated percentage 5.13%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandTwentyTwoMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		      
Secured Debt 250,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandTwentyTwoMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 250,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandTwentyTwoMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		    
Avista Corporation [Member] | 2023, 7.18% - 7.54% [Member] | Secured Debt [Member]        
Debt Instrument [Line Items]        
Maturity Year 2023      
Medium-Term Notes, Noncurrent 13,500us-gaap_MediumtermNotesNoncurrent
/ us-gaap_DebtInstrumentAxis
= ava_TwoThosuandTwentyThreeSevenPointOneEightPercentageToSevenPointFiveFourPercentageMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		 13,500us-gaap_MediumtermNotesNoncurrent
/ us-gaap_DebtInstrumentAxis
= ava_TwoThosuandTwentyThreeSevenPointOneEightPercentageToSevenPointFiveFourPercentageMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		    
Avista Corporation [Member] | 2028 [Member] | Secured Debt [Member]        
Debt Instrument [Line Items]        
Maturity Year 2028      
Debt instrument, interest rate, stated percentage 6.37%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandTwentyEightMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		      
Medium-Term Notes, Noncurrent 25,000us-gaap_MediumtermNotesNoncurrent
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandTwentyEightMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		 25,000us-gaap_MediumtermNotesNoncurrent
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandTwentyEightMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		    
Avista Corporation [Member] | 2032 [Member] | Secured Debt [Member]        
Debt Instrument [Line Items]        
Maturity Year 2032 [3]      
Pollution Control Bonds 66,700us-gaap_LongTermPollutionControlBond
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandThirtyTwoMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		 [3] 66,700us-gaap_LongTermPollutionControlBond
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandThirtyTwoMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		 [3]    
Avista Corporation [Member] | 2034 [Member] | Secured Debt [Member]        
Debt Instrument [Line Items]        
Maturity Year 2034 [2]      
Pollution Control Bonds 17,000us-gaap_LongTermPollutionControlBond
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandThirtyFourMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		 [2] 17,000us-gaap_LongTermPollutionControlBond
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandThirtyFourMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember		 [2]    
Avista Corporation [Member] | 2035 [Member] | First Mortgage [Member]        
Debt Instrument [Line Items]        
Maturity Year 2035      
Debt instrument, interest rate, stated percentage 6.25%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandThirtyFiveMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		      
Secured Debt 150,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandThirtyFiveMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 150,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandThirtyFiveMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		    
Avista Corporation [Member] | 2037 [Member] | First Mortgage [Member]        
Debt Instrument [Line Items]        
Maturity Year 2037      
Debt instrument, interest rate, stated percentage 5.70%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandThirtySevenMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		      
Secured Debt 150,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandThirtySevenMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 150,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandThirtySevenMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		    
Avista Corporation [Member] | 2040 [Member] | First Mortgage [Member]        
Debt Instrument [Line Items]        
Maturity Year 2040      
Debt instrument, interest rate, stated percentage 5.55%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandFortyMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		      
Secured Debt 35,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandFortyMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 35,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandFortyMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		    
Avista Corporation [Member] | 2041 [Member] | First Mortgage [Member]        
Debt Instrument [Line Items]        
Maturity Year 2041      
Debt instrument, interest rate, stated percentage 4.45%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandFortyOneMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		      
Secured Debt 85,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandFortyOneMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 85,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandFortyOneMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		    
Avista Corporation [Member] | 2047 [Member] | First Mortgage [Member]        
Debt Instrument [Line Items]        
Maturity Year 2047      
Debt instrument, interest rate, stated percentage 4.23%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandFortySevenMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		      
Secured Debt 80,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandFortySevenMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		 80,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandFortySevenMember
/ dei_LegalEntityAxis
= ava_AvistaCorporationMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_FirstMortgageMember		    
Alaska Energy Resources Company [Member] | 2019 [Member] | Unsecured Debt [Member]        
Debt Instrument [Line Items]        
Maturity Year 2019 [5]      
Debt instrument, interest rate, stated percentage 3.85%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandNineteenMember
/ dei_LegalEntityAxis
= ava_AlaskaEnergyResourcesCompanyMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember		 [5]      
Unsecured Debt $ 15,000us-gaap_UnsecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandNineteenMember
/ dei_LegalEntityAxis
= ava_AlaskaEnergyResourcesCompanyMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember		 [5] $ 0us-gaap_UnsecuredDebt
/ us-gaap_DebtInstrumentAxis
= ava_TwoThousandNineteenMember
/ dei_LegalEntityAxis
= ava_AlaskaEnergyResourcesCompanyMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember		 [5]    
[1] Upon settlement of interest rate swaps, these are recorded as a regulatory asset or liability and included as part of long-term debt above. They are amortized as a component of interest expense over the life of the associated debt and included as a part of the Company's cost of debt calculation for ratemaking purposes.
[2] In December 2014, Avista Corp. issued $60.0 million of first mortgage bonds to three institutional investors in a private placement transaction. The first mortgage bonds bear an interest rate of 4.11 percent and mature in 2044. The total net proceeds from the sale of the new bonds were used to repay a portion of the borrowings outstanding under the Company’s $400.0 million committed line of credit and for general corporate purposes.
[3] In December 2010, $66.7 million and $17.0 million of the City of Forsyth, Montana Pollution Control Revenue Refunding Bonds (Avista Corporation Colstrip Project) due in 2032 and 2034, respectively, which had been held by Avista Corp. since 2008 and 2009, respectively, were refunded by new bond issues (Series 2010A and Series 2010B). The new bonds were not offered to the public and were purchased by Avista Corp. due to market conditions. The Company expects that at a later date, subject to market conditions, these bonds may be remarketed to unaffiliated investors. So long as Avista Corp. is the holder of these bonds, the bonds will not be reflected as an asset or a liability on Avista Corp.'s Consolidated Balance Sheets.
[4] In September 2014, AEL&P issued $75.0 million of 4.54 percent first mortgage bonds due in 2044 to two institutional investors in the private placement market. The first mortgage bonds were issued under and in accordance with the AEL&P Mortgage and Deed of Trust, dated as of July 1, 2014.
[5] In December 2014, AERC issued a $15.0 million unsecured term loan note due in 2019 to a national cooperative bank. The term note bears an interest rate of 3.85 percent.