XML 70 R58.htm IDEA: XBRL DOCUMENT
v3.20.2

Subsequent Events (Details) | Oct. 22, 2020
--- | ---
Subsequent Event [Member] | Grundartangi [Member] |
Subsequent Event [Line Items] |
Labor agreement period | 5 years

X
- Definition Labor Agreement Period + References No definition available. + Details
Name: | cenx_LaborAgreementPeriod
Namespace Prefix: | cenx_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
Name: | us-gaap_SubsequentEventLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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