Debt Instrument, Basis Spread Adjustment

No definition available.

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Namespace Prefix:	cenx_
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Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
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-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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-Topic 470
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-Section 50
-Paragraph 1B
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 470
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477734/942-470-50-3

+ Details

Name:	us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 14
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-14

+ Details

Name:	us-gaap_ProceedsFromDebtNetOfIssuanceCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash outflow for short-term and long-term debt. Excludes payment of lease obligation.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 15
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-15

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow to repay long-term debt that is wholly or partially secured by collateral. Excludes repayments of tax exempt secured debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
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-Subparagraph (b)
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-URI https://asc.fasb.org/1943274/2147482740/230-10-45-15

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
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-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483399/855-10-50-2

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- Details

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- Details

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- Details

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- Details

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- Details

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Balance Type:
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- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_ForeignLineOfCreditMember
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- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_RevolvingCreditFacilityMember
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- Details

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Subsequent Events (Details) - USD ($) $ in Millions	Aug. 05, 2025	Aug. 01, 2025	Jul. 22, 2025	Jun. 30, 2025	Oct. 01, 2024	Dec. 09, 2022
Senior Secured Notes Due 2032 \| Senior notes \| Subsequent Event
Subsequent Event [Line Items]
Face amount			$ 400.0
Stated interest rate, percentage			6.875%
Proceeds from issuance after financing fees and expenses			$ 395.0
Senior Notes Due 2028 \| Senior notes \| Subsequent Event
Subsequent Event [Line Items]
Redemption of debt	$ 261.1
Redemption price, percentage	101.875%
Vlissingen Credit Facility \| Foreign line of credit
Subsequent Event [Line Items]
Face amount						$ 90.0
Stated interest rate, percentage				7.98%	8.75%
Vlissingen Credit Facility \| Subsequent Event \| Foreign line of credit
Subsequent Event [Line Items]
Repayments of vilissingen credit facilty		$ 10.0
U.S. revolving credit facility \| Foreign line of credit
Subsequent Event [Line Items]
Stated interest rate, percentage				7.82%
U.S. revolving credit facility \| U.S. revolving credit facility
Subsequent Event [Line Items]
Stated interest rate, percentage				8.00%
U.S. revolving credit facility \| Subsequent Event \| U.S. revolving credit facility
Subsequent Event [Line Items]
Basis spread adjustment			0.10%