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Forward delivery contracts and financial instruments (Details) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2014 t | Dec. 31, 2013 t
Long-Term Tolling Contracts [Member] | Glencore Toll Agreement 1 [Member] |  |  |
Supply Commitment [Line Items] |  |  |
Annual Primary Aluminum Physical Delivery Contract_Maximum | 90,000 cenx_AnnualPrimaryAluminumPhysicalDeliveryContract_Maximum / cenx_NameOfContractAxis = cenx_GlencoreTollAgreement1Member / us-gaap_SupplyCommitmentAxis = cenx_LongTermTollingContractsMember |  |
Customer | Glencore |  |
Volume | 90,000 tonnes per year ("tpy") |  |
Term | Through July 2016 |  |
Pricing | Variable, based on LME and European Duty Paid premium |  |
Primary Aluminum Sales Contracts [Member] | Glencore Nordural Metal Agreement [Member] |  |  |
Supply Commitment [Line Items] |  |  |
Annual Primary Aluminum Physical Delivery Contract_Maximum | 205,000 cenx_AnnualPrimaryAluminumPhysicalDeliveryContract_Maximum / cenx_NameOfContractAxis = cenx_GlencoreNorduralMetalAgreementMember / us-gaap_SupplyCommitmentAxis = cenx_PrimaryAluminumSalesContractsMember |  |
Customer | Glencore | [1] |
Volume | All primary aluminum produced at Grundartangi, net of tolling and other sales commitments | [1] |
Term | January 1, 2014 through December 31, 2017 | [1] |
Pricing | Variable, based on LME and European Duty Paid premium and product premiums, as applicable | [1] |
Other Forward Delivery Contracts [Member] |  |  |
Supply Commitment [Line Items] |  |  |
Other forward delivery contracts to sell primary aluminum (in tonnes) | 6,108 cenx_OtherPrimaryAluminumDeliveryCommitmentsAndContractsVolume / us-gaap_SupplyCommitmentAxis = us-gaap_ForwardContractsMember |  | 118,373 cenx_OtherPrimaryAluminumDeliveryCommitmentsAndContractsVolume / us-gaap_SupplyCommitmentAxis = us-gaap_ForwardContractsMember
Glencore [Member] | Other Forward Delivery Contracts [Member] |  |  |
Supply Commitment [Line Items] |  |  |
Other forward delivery contracts to sell primary aluminum (in tonnes) | 4,058 cenx_OtherPrimaryAluminumDeliveryCommitmentsAndContractsVolume / dei_LegalEntityAxis = cenx_GlencoreMember / us-gaap_SupplyCommitmentAxis = us-gaap_ForwardContractsMember |  | 20,008 cenx_OtherPrimaryAluminumDeliveryCommitmentsAndContractsVolume / dei_LegalEntityAxis = cenx_GlencoreMember / us-gaap_SupplyCommitmentAxis = us-gaap_ForwardContractsMember
[1] | The Glencore Grundartangi Metal Agreement is for all metal produced at Grundartangi from 2014 through 2017 less commitments under existing tolling and other sales contracts. Grundartangi currently estimates that it will sell Glencore approximately 205,000 tonnes of aluminum under this agreement in 2015.

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- Definition Annual Primary Aluminum Physical Delivery Contract (Maximum) + References No definition available. + Details
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Namespace Prefix: | cenx_
Data Type: | num:massItemType
Balance Type: | na
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- Definition Long Term Contract For Purchase Of Primary Aluminum, Contract Expiration Date + References No definition available. + Details
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Namespace Prefix: | cenx_
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Balance Type: | na
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- Definition The description of the pricing terms for long term sales contracts. + References No definition available. + Details
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- Definition The name of a particular customer for a company. + References No definition available. + Details
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- Definition Total amount of primary aluminum committed to be supplied under existing contracts or agreements outside of major long-term supply commitments. + References No definition available. + Details
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Namespace Prefix: | cenx_
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- Definition Description of the particular sales volume for a particular customer. + References No definition available. + Details
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- Details
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- Details
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- Details
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Namespace Prefix: |
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- Details
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- Details
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