XML 74 R63.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Business, Product and Geographical Area Information and Concentration of Risk, Narrative (Details) - productionfacilities | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | Dec. 31, 2017
Segment Reporting Information |  |  |  |  |
Percentage of employees covered by collective bargaining agreements | 61.00% |  | 61.00% |  |
Percentage of employees covered by collective bargaining agreements expiring within one year | 0.00% |  | 0.00% |  |
Domestic |  |  |  |  |
Segment Reporting Information |  |  |  |  |
Number of production facilities |  |  | 12 |  |
Foreign |  |  |  |  |
Segment Reporting Information |  |  |  |  |
Number of production facilities |  |  | 1 |  |
Customer Concentration Risk | Largest Customer | Sales Revenue, Net |  |  |  |  |
Segment Reporting Information |  |  |  |  |
Concentration percentages (percent) | 26.00% | 27.00% | 26.00% | 28.00% |
Customer Concentration Risk | Largest Customer | Accounts Receivable |  |  |  |  |
Segment Reporting Information |  |  |  |  |
Concentration percentages (percent) |  |  | 24.00% |  | 22.00%
Customer Concentration Risk | Second Largest Customer | Sales Revenue, Net |  |  |  |  |
Segment Reporting Information |  |  |  |  |
Concentration percentages (percent) | 15.00% | 11.00% | 13.00% | 10.00% |
Customer Concentration Risk | Second Largest Customer | Accounts Receivable |  |  |  |  |
Segment Reporting Information |  |  |  |  |
Concentration percentages (percent) |  |  | 15.00% |  | 14.00%

X
- Definition Number of Production Facilities. + References No definition available. + Details
Name: | kalu_NumberOfProductionFacilities
Namespace Prefix: | kalu_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

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 For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13531-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13537-108611 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592 + Details
Name: | us-gaap_ConcentrationRiskPercentage1
Namespace Prefix: | us-gaap_
Data Type: | num: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_SegmentReportingInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_StatementGeographicalAxis=country_US
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_CA
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CustomerConcentrationRiskMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=kalu_LargestCustomerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueNetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_AccountsReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=kalu_SecondLargestCustomerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |