XML 47 R35.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Ravenswood impairment (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2016 | Jun. 30, 2015 | Jun. 30, 2016 | Jun. 30, 2015
Impaired Assets to be Disposed of by Method Other than Sale [Line Items] |  |  |  |
Ravenswood impairment | $ 0 | $ 30,850 | $ 0 | $ 30,850
Ravenswood Aluminum Smelter [Member] |  |  |  |
Impaired Assets to be Disposed of by Method Other than Sale [Line Items] |  |  |  |
Ravenswood impairment |  | $ 30,850 |  |

X
- Definition Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2420-110228 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585 + Details
Name: | us-gaap_AssetImpairmentCharges
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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_ImpairedAssetsToBeDisposedOfByMethodOtherThanSaleLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=cenx_RavenswoodAluminumSmelterMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |