XML 128 R93.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Pension Plans and Other Postretirement Benefit Plans - Additional Information (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items] |  |  |
Payment for pension benefits | $ 42,000 | $ 22,000 | $ 22,000
Percentage of service related net periodic benefit costs capitalized to utility property | 40.00% |  |
Percentage of service related net periodic benefit costs recorded to operating expenses | 60.00% |  |
Deferred Compensation, Excluding Share-based Payments and Retirement Benefits [Member] | Executive Officer [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Deferred compensation, earlier of retirement, termination, disability or death, percent | 75.00% |  |
Deferred compensation incentive payments, percent | 100.00% |  |
Equity Securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target investment allocation | 55.00% | 35.00% |
Debt Securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target investment allocation | 40.00% | 49.00% |
Real Estate [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target investment allocation | 5.00% | 7.00% |
Absolute Return [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target investment allocation | 0.00% | 9.00% |
Pension Plans, Defined Benefit [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Expected contributions to pension plan | $ 42,000 |  |
Other Postretirement Benefits [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Expected contributions to pension plan | $ 7,200 |  |
Other Postretirement Benefits [Member] | Equity Securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target investment allocation | 60.00% | 60.00% |
Other Postretirement Benefits [Member] | Debt Securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target investment allocation | 40.00% | 40.00% |

X
- Definition Deferred Compensation, Maximum Incentive Payments + References No definition available. + Details
Name: | ava_DeferredCompensationMaximumIncentivePayments
Namespace Prefix: | ava_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Deferred Compensation, Maximum Salary + References No definition available. + Details
Name: | ava_DeferredCompensationMaximumSalary
Namespace Prefix: | ava_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of service related net periodic benefit costs capitalized to utility property. + References No definition available. + Details
Name: | ava_PercentageOfServiceRelatedNetPeriodicBenefitCostsCapitalizedToUtilityProperty
Namespace Prefix: | ava_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of service related net periodic benefit costs recorded to operating expenses. + References No definition available. + Details
Name: | ava_PercentageOfServiceRelatedNetPeriodicBenefitCostsRecordedToOperatingExpenses
Namespace Prefix: | ava_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of contribution expected to be received by defined benefit plan from employer in next fiscal year following current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=123450688&loc=d3e4587-114921 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of cash outflow for pension benefit. Includes, but is not limited to, employer contribution to fund plan asset and payment to retiree. Excludes other postretirement benefit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3536-108585 + Details
Name: | us-gaap_PensionContributions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_DeferredCompensationArrangementWithIndividualExcludingShareBasedPaymentsAndPostretirementBenefitsByTypeOfDeferredCompensationAxis=us-gaap_DeferredCompensationExcludingShareBasedPaymentsAndRetirementBenefitsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_TitleOfIndividualAxis=srt_ExecutiveOfficerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_RealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=ava_AbsoluteReturnMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |