XML 69 R58.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Debt - 7.5% Notes Due 2021 (Details) - USD ($) | Jun. 04, 2013 | Mar. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | --- | --- | ---
Debt Instrument [Line Items] |  |  |  |
Fair value of debt instrument |  | $ 250,000,000 | $ 234,220,000 |
Long-term Debt [Member] | Senior secured notes due June 01, 2021 [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Face amount | $ 250,000,000 |  |  |
Proceeds from debt issuance | $ 246,330,000 |  |  |
Stated interest rate | 7.50% | 7.50% | 7.50% | 7.50%
Fair value of debt instrument |  |  | $ 234,220,000 | $ 169,220,000
Equity interests in foreign subsidiaries, percentage |  |  | 65.00% |

X
- Definition The debt instrument is secured by a pledge of and lien on 65% of equity interests in foreign subsidiaries or foreign holding companies directly owned by Century and the guarantors. + References No definition available. + Details
Name: | cenx_DebtInstrumentCollateralEquityInterestsinForeignSubsidiaries
Namespace Prefix: | cenx_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13433-108611 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13476-108611 + Details
Name: | us-gaap_DebtInstrumentFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt. + References No definition available. + Details
Name: | us-gaap_ProceedsFromIssuanceOfDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_LongTermDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=cenx_SeniorsecurednotesdueJune012021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |