XML 35 R10.htm IDEA: XBRL DOCUMENT  v2.3.0.11

Income Taxes	6 Months Ended
	Jun. 30, 2011
Notes to Financial Statements [Abstract]
Income Taxes	As of June 30, 2011 and December 31, 2010, we had total unrecognized tax benefits (excluding interest) of $17,803 and $16,640, respectively.  The total amount of unrecognized tax benefits (including interest and net of federal benefit) that, if recognized, would affect the effective tax rate as of June 30, 2011 and December 31, 2010, respectively, are approximately $1,684 and $1,651. We recognize interest and penalties accrued related to unrecognized tax benefits in income tax expense.  As of June 30, 2011 and December 31, 2010, we had approximately $471 and $300, respectively, of accrued interest related to unrecognized income tax benefits. We do not expect a significant change in the balance of unrecognized tax benefits within the next twelve months. Our federal income tax returns beginning in 2007 are subject to examination.  Material state and local income tax matters have been concluded for years through 2002.  The majority of our state returns beginning in 2005 are subject to examination.  Our Icelandic tax returns are subject to examination and income tax matters have been concluded for years through 2001.

X

- Details

Name:	cenx_NotesToFinancialStatementsAbstract
Namespace Prefix:	cenx
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Description containing the entire income tax disclosure. Examples include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information. This element may be used as a single block of text to encapsulate the entire disclosure including data and tables.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph h
-Article 4

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 136, 172

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 43, 44, 45, 46, 47, 48, 49

+ Details

Name:	us-gaap_IncomeTaxDisclosureTextBlock
Namespace Prefix:	us-gaap
Data Type:	us-types:textBlockItemType
Balance Type:	na
Period Type:	duration