v2.3.0.15

Employee Incentive Plans, Unrecognized Gross Compensation Cost Data Table (Details) (USD $) In Millions, unless otherwise specified | 9 Months Ended
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Sep. 30, 2011 years
Service-based vested and non-vested common shares and restricted stock units [Member] |
Unrecognized gross compensation cost data |
Unrecognized gross compensation costs, by award type | $ 4.5
Expected period (in years) over which the remaining gross compensation costs will be recognized |
Expected period (in years) over which the remaining gross compensation costs will be recognized, by award type | 1.9
Performance Shares [Member] |
Unrecognized gross compensation cost data |
Unrecognized gross compensation costs, by award type | $ 4.7
Expected period (in years) over which the remaining gross compensation costs will be recognized |
Expected period (in years) over which the remaining gross compensation costs will be recognized, by award type | 2.2

X
- Definition Expected period (in years) over which the remaining gross compensation costs will be recognized, by type of award: + Details
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Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Unrecognized gross compensation cost data relating to the Equity Incentive Plan . + Details
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Namespace Prefix: | kalu
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph h -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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Namespace Prefix: | us-gaap
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, using a decimal to express in number of years. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph h -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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Namespace Prefix: | us-gaap
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration