XML 13 R39.htm IDEA: XBRL DOCUMENT
v3.2.0.727

Summary of Significant Accounting Policies, Textuals (Details) - USD ($) $ in Millions | Jun. 30, 2015 | Dec. 31, 2014
--- | --- | ---
Significant accounting policies |  |
Percentage of Employees Covered by Collective Bargaining Agreements | 63.00% |
Percentage of Employees Covered by Collective Bargaining Agreements Expiring Within One Year | 0.00% |
Fabricated Products |  |
Significant accounting policies |  |
Excess of current cost over the stated LIFO value of inventory | $ 10.2 | $ 37.6

X
- Definition Percentage of Employees Covered by Collective Bargaining Agreements + References No definition available. + Details
Name: | kalu_PercentageofEmployeesCoveredbyCollectiveBargainingAgreements
Namespace Prefix: | kalu_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of Employees Covered by Collective Bargaining Agreements Expiring Within One Year + References No definition available. + Details
Name: | kalu_PercentageofEmployeesCoveredbyCollectiveBargainingAgreementsExpiringWithinOneYear
Namespace Prefix: | kalu_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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
- Definition Amount of difference between inventory at lower of LIFO cost or market and inventory at lower of other inventory accounting method cost or market, for example, but not limited to, FIFO or average cost. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.6(c)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_InventoryLIFOReserve
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=kalu_FabricatedProductsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |