XML 88 R75.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Multiemployer Pension Plans - Multiemployer Pension Plan Description and Contributions (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Multiemployer Pension Plan Disclosure [Line Items] |  |  |
Entity Tax Identification Number | 94-3030279 |  |
Contributions of the Company | $ 5.0 | $ 4.9 | $ 5.0
USW Plan |  |  |
Multiemployer Pension Plan Disclosure [Line Items] |  |  |
Entity Tax Identification Number | 23-6648508 |  |
Pension Protection Act Zone Status | Green | Green |
FIP/RP Status Pending/Implemented in 2021 | No |  |
Contributions of the Company | $ 3.6 | $ 3.8 | 3.8
Surcharge Imposed in 2021 |  | No |
USW Plan | Minimum |  |  |
Multiemployer Pension Plan Disclosure [Line Items] |  |  |
Expiration Date of Collective-Bargaining Agreement | Sep. 30, 2025 |  |
USW Plan | Maximum |  |  |
Multiemployer Pension Plan Disclosure [Line Items] |  |  |
Expiration Date of Collective-Bargaining Agreement | Nov. 30, 2026 |  |
Other Funds |  |  |
Multiemployer Pension Plan Disclosure [Line Items] |  |  |
Contributions of the Company | $ 1.4 | $ 1.1 | $ 1.2

X
- Definition The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Exchange Act -Number 240 -Section 12 -Subsection b-2 + Details
Name: | dei_EntityTaxIdentificationNumber
Namespace Prefix: | dei_
Data Type: | dei:employerIdItemType
Balance Type: | na
Period Type: | duration

X
- Definition Multiemployer Pension Plan Disclosure [Line Items] + References No definition available. + Details
Name: | kalu_MultiemployerPensionPlanDisclosureLineItems
Namespace Prefix: | kalu_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Indicates certified zone status of multiemployer pension plan determined to be individually significant. Acceptable values are "Green", "Yellow", "Orange", "Red", "Other", and "NA". + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=35742348&loc=SL14450788-114948 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 5 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947 + Details
Name: | us-gaap_MultiemployerPlanPensionSignificantCertifiedZoneStatusFixedList
Namespace Prefix: | us-gaap_
Data Type: | us-types:zoneStatusItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expiration date of collective-bargaining arrangement (CBA) requiring contribution to multiemployer pension plan determined to be individually significant, in YYYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=35742348&loc=SL14450788-114948 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 5 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947 + Details
Name: | us-gaap_MultiemployerPlanPensionSignificantCollectiveBargainingArrangementExpirationDate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of cost for employer contribution to multiemployer pension plan determined to be individually significant. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 5 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=35742348&loc=SL14450788-114948 + Details
Name: | us-gaap_MultiemployerPlanPensionSignificantEmployerContributionCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Indicates whether funding improvement plan or rehabilitation plan was implemented or pending for multiemployer pension plan, determined to be individually significant. Acceptable values are "No", "Pending", "Implemented", "Other", and "NA". + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=35742348&loc=SL14450788-114948 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 5 -Subparagraph (f)(1) -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947 + Details
Name: | us-gaap_MultiemployerPlanPensionSignificantFundingImprovementOrRehabilitationPlanImplementationStatusFixedList
Namespace Prefix: | us-gaap_
Data Type: | us-types:fundingImprovementAndRehabilitationPlanItemType
Balance Type: | na
Period Type: | duration

X
- Definition Indicates whether employer paid surcharge to multiemployer pension plan determined to be individually significant. Acceptable values are "No", "Yes" and "NA". + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=35742348&loc=SL14450788-114948 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 5 -Subparagraph (f)(2) -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947 + Details
Name: | us-gaap_MultiemployerPlanPensionSignificantSurchargeFixedList
Namespace Prefix: | us-gaap_
Data Type: | us-types:surchargeItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=kalu_UswaPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=kalu_PensionPlanIndividuallyInsignificantMultiemployerPlansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |