XML 62 R50.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Summary of Significant Accounting Policies - Schedule of Total Government Assistance Recognized (Details) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 USD ($)
Government Grant |
Significant Accounting Policies [Line Items] |
Government assistance recognized amount | $ 1.6
IN EDGE Tax Credit | Indiana Economic Development Corporation | Cost of Products Sold |
Significant Accounting Policies [Line Items] |
Government assistance recognized amount | $ 1.6
IN EDGE Tax Credit | Indiana Economic Development Corporation | Cost of Products Sold | Minimum |
Significant Accounting Policies [Line Items] |
Government grants transaction duration | 2021
IN EDGE Tax Credit | Indiana Economic Development Corporation | Cost of Products Sold | Maximum |
Significant Accounting Policies [Line Items] |
Government grants transaction duration | 2030

X
- Definition Government grants transaction duration. + References No definition available. + Details
Name: | kalu_GovernmentGrantsTransactionDuration
Namespace Prefix: | kalu_
Data Type: | dtr-types:gYearListItemType
Balance Type: | na
Period Type: | duration

X
- Definition Proceeds from government grants. + References No definition available. + Details
Name: | kalu_ProceedsFromGovernmentGrants
Namespace Prefix: | kalu_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Significant accounting policies [Line Items] + References No definition available. + Details
Name: | kalu_SignificantAccountingPoliciesLineItems
Namespace Prefix: | kalu_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_GovernmentAssistanceTypeAxis=kalu_GovernmentGrantMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GovernmentAssistanceTypeAxis=kalu_InEdgeTaxCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=kalu_IndianaEconomicDevelopmentCorporationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=us-gaap_CostOfSalesMember
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: |