Income taxes	9 Months Ended
Sep. 30, 2013
Income Tax Disclosure [Abstract]
Income taxes	Income taxes We recorded income tax expense for the nine months ended September 30, 2013 of $4,714 which primarily consisted of foreign and state income taxes, net of a release of a valuation allowance as disclosed in Note 2 Acquisition of Sebree aluminum smelter. Our domestic deferred tax assets, net of deferred tax liabilities, are subject to a valuation allowance; therefore, the domestic losses were not benefited. We recorded income tax expense for the nine months ended September 30, 2012 of $7,384 which primarily consisted of foreign and state income taxes. Income tax expense is based on an annual effective tax rate forecast, including estimates and assumptions that could change during the year. As of September 30, 2013, all of Century's U.S. and certain foreign deferred tax assets, net of deferred tax liabilities, continue to be subject to a valuation allowance. The realization of these assets is dependent on substantial future taxable income which, at September 30, 2013, is not more likely than not to be achieved. In April 2013, we received notice from the Internal Revenue Service ("IRS") that the Congressional Joint Committee on Taxation finalized their review of the US Federal examinations for the income tax years 2008, 2009, and 2010 and refund years of 2004, 2005, 2006, and 2007 without exception to the conclusions reached by the IRS. This Joint Committee is a special nonpartisan Congressional committee involved with the analysis and drafting of federal tax legislation and, as part of its mandate, reviews all federal tax refund claims over a certain amount. As a result of this determination, we have reduced the reserve for the unrecognized tax benefits related to prior years by $14,341. The reduction did not result in an impact to the effective tax rate since the reduction was offset by an increase in our valuation allowance. During the second quarter of 2013, we received refunds from the IRS of $5,009 following the Joint Committee review. During the second quarter of 2013, we received notice from the Directorate of Internal Revenue of Iceland of their intent to conduct a periodic review regarding certain of our Icelandic subsidiaries for the years 2010-2012.

Income taxes

9 Months Ended

Sep. 30, 2013

We recorded income tax expense for the nine months ended September 30, 2013 of $4,714 which primarily consisted of foreign and state income taxes, net of a release of a valuation allowance as disclosed in Note 2 Acquisition of Sebree aluminum smelter. Our domestic deferred tax assets, net of deferred tax liabilities, are subject to a valuation allowance; therefore, the domestic losses were not benefited.

We recorded income tax expense for the nine months ended September 30, 2012 of $7,384 which primarily consisted of foreign and state income taxes.

Income tax expense is based on an annual effective tax rate forecast, including estimates and assumptions that could change during the year.

As of September 30, 2013, all of Century's U.S. and certain foreign deferred tax assets, net of deferred tax liabilities, continue to be subject to a valuation allowance. The realization of these assets is dependent on substantial future taxable income which, at September 30, 2013, is not more likely than not to be achieved.

In April 2013, we received notice from the Internal Revenue Service ("IRS") that the Congressional Joint Committee on Taxation finalized their review of the US Federal examinations for the income tax years 2008, 2009, and 2010 and refund years of 2004, 2005, 2006, and 2007 without exception to the conclusions reached by the IRS. This Joint Committee is a special nonpartisan Congressional committee involved with the analysis and drafting of federal tax legislation and, as part of its mandate, reviews all federal tax refund claims over a certain amount. As a result of this determination, we have reduced the reserve for the unrecognized tax benefits related to prior years by $14,341. The reduction did not result in an impact to the effective tax rate since the reduction was offset by an increase in our valuation allowance. During the second quarter of 2013, we received refunds from the IRS of $5,009 following the Joint Committee review.

During the second quarter of 2013, we received notice from the Directorate of Internal Revenue of Iceland of their intent to conduct a periodic review regarding certain of our Icelandic subsidiaries for the years 2010-2012.