XML 106 R122.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Asset retirement obligations (“ARO”) (Details) (USD $) In Thousands, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2014 | Dec. 31, 2013
Asset Retirement Obligation [Roll Forward] |  |
Beginning balance, ARO liability | $ 27,113 us-gaap_AssetRetirementObligation | $ 16,124 us-gaap_AssetRetirementObligation
Additional ARO liability incurred | 2,548 us-gaap_AssetRetirementObligationLiabilitiesIncurred | 1,730 us-gaap_AssetRetirementObligationLiabilitiesIncurred
ARO liabilities settled | (4,731)us-gaap_AssetRetirementObligationLiabilitiesSettled | (2,580)us-gaap_AssetRetirementObligationLiabilitiesSettled
Accretion expense | 1,517 us-gaap_AssetRetirementObligationAccretionExpense | 1,733 us-gaap_AssetRetirementObligationAccretionExpense
Ending balance, ARO liability | 36,950 us-gaap_AssetRetirementObligation | 27,113 us-gaap_AssetRetirementObligation
Sebree Smelter [Member] |  |
Asset Retirement Obligation [Roll Forward] |  |
Additional ARO liability from acquisitions | 0 cenx_BusinessAcquisitionPurchasePriceAllocationAssetRetirementObligation / us-gaap_BusinessAcquisitionAxis = cenx_SebreeSmelterMember | 10,106 cenx_BusinessAcquisitionPurchasePriceAllocationAssetRetirementObligation / us-gaap_BusinessAcquisitionAxis = cenx_SebreeSmelterMember
Mt. Holly Smelter [Member] |  |
Asset Retirement Obligation [Roll Forward] |  |
Additional ARO liability from acquisitions | $ 10,503 cenx_BusinessAcquisitionPurchasePriceAllocationAssetRetirementObligation / us-gaap_BusinessAcquisitionAxis = cenx_Mt.HollySmelterMember | $ 0 cenx_BusinessAcquisitionPurchasePriceAllocationAssetRetirementObligation / us-gaap_BusinessAcquisitionAxis = cenx_Mt.HollySmelterMember

X
- Definition The amount of acquisition cost of a business combination allocated to asset retirement obligation of the acquired entity. + References No definition available. + Details
Name: | cenx_BusinessAcquisitionPurchasePriceAllocationAssetRetirementObligation
Namespace Prefix: | cenx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Asset Retirement Obligation -URI http://asc.fasb.org/extlink&oid=6505190 + Details
Name: | us-gaap_AssetRetirementObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6392676&loc=d3e7480-110848 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_AssetRetirementObligationAccretionExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of asset retirement obligations incurred during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_AssetRetirementObligationLiabilitiesIncurred
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_AssetRetirementObligationLiabilitiesSettled
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_AssetRetirementObligationRollForwardAnalysisRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=cenx_Mt.HollySmelterMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=cenx_SebreeSmelterMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |