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Fair value measurements (Tables) | 9 Months Ended
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Sep. 30, 2013
Fair Value Disclosures [Abstract] |
Schedule of valuation methodology used to measure assets and liabilities at fair value | The following section describes the valuation methodology used to measure our financial assets and liabilities that were accounted for at fair value and are categorized based on the fair value hierarchy described in ASC 820 "Fair Value Measurements."
Overview of Century’s valuation methodology
| Level | Significant inputs
Cash equivalents | 1 | Quoted market prices
Trust assets (1) | 1 | Quoted market prices
Surety bonds | 1 | Quoted market prices
E.ON U.S. (“E.ON”) contingent obligation | 3 | Quoted LME forward market, management’s estimates of the LME forward market prices for periods beyond the quoted periods and management’s estimate of future level of operations at Century Aluminum of Kentucky, our wholly owned subsidiary (“CAKY”)
Primary aluminum sales premium contracts | 3 | Management’s estimates of future U.S. Midwest premium and risk-adjusted discount rates
Midwest premium contracts | 3 | Management’s estimates of future U.S. Midwest premium
(1) | Trust assets are currently invested in money market funds. These trust assets are held to fund the non-qualified supplemental executive pension benefit obligations for certain of our officers. The trust has sole authority to invest the funds in secure interest producing investments consisting of short-term securities issued or guaranteed by the United States government or cash and cash equivalents.
Financial assets and liabilities at fair value on a recurring basis | The following table sets forth our financial assets and liabilities that were accounted for at fair value on a recurring basis by the level of input within the ASC 820 fair value hierarchy. As required by GAAP for fair value measurements and disclosures, financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of fair value assets and liabilities and the placement within the fair value hierarchy levels. There were no transfers between Level 1 and 2 during the periods presented. There were no transfers into or out of Level 3 during the periods presented below. It is our policy to recognize transfers into and transfers out of Level 3 as of the actual date of the event or change in circumstances that caused the transfer.
Recurring Fair Value Measurements | As of September 30, 2013
| Level 1 | Level 2 | Level 3 | Total
ASSETS: |  |  |  |
Cash equivalents | $ | 119,183 |  | $ | — |  | $ | — |  | $ | 119,183 |
Trust assets (1) | 11,588 |  | — |  | — |  | 11,588 |
Surety bonds | 1,574 |  | — |  | — |  | 1,574 |
Midwest premium contracts | — |  | — |  | 363 |  | 363 |
TOTAL | $ | 132,345 |  | $ | — |  | $ | 363 |  | $ | 132,708 |
LIABILITIES: |  |  |  |
E.ON contingent obligation – net (2) | $ | — |  | $ | — |  | $ | — |  | $ | — |
Primary aluminum sales contract | — |  | — |  | 771 |  | 771 |
TOTAL | $ | — |  | $ | — |  | $ | 771 |  | $ | 771 |
(1) | Trust assets are currently invested in money market funds.
(2) | Based on the LME forward market prices for primary aluminum at September 30, 2013 and management's estimate of the LME forward market for periods beyond the quoted periods, we believe that we will not have any payment obligations for the E.ON contingent obligation through the term of the agreement which expires in 2028. See Note 10 Debt for additional information about the E.ON contingent obligation fair value.
Recurring Fair Value Measurements | As of December 31, 2012
| Level 1 | Level 2 | Level 3 | Total
ASSETS: |  |  |  |
Cash equivalents | $ | 168,309 |  | $ | — |  | $ | — |  | $ | 168,309 |
Trust assets (1) | 14,254 |  | — |  | — |  | 14,254 |
Surety bonds | 2,123 |  | — |  | — |  | 2,123 |
TOTAL | $ | 184,686 |  | $ | — |  | $ | — |  | $ | 184,686 |
LIABILITIES: |  |  |  |
E.ON contingent obligation – net | $ | — |  | $ | — |  | $ | 15,369 |  | $ | 15,369 |
Primary aluminum sales contract | — |  | — |  | 1,170 |  | 1,170 |
TOTAL | $ | — |  | $ | — |  | $ | 16,539 |  | $ | 16,539 |
(1) | Trust assets are currently invested in money market funds.
Change in level 3 fair value measurements |
Change in Level 3 Fair Value Measurements during the three months ended September 30,
| Derivative liabilities - net
| 2013 | 2012
Beginning balance, July 1, | $ | (773 | ) | $ | (16,024 | )
Total gain (loss) included in earnings | 365 |  | (371 | )
Ending balance, September 30, | $ | (408 | ) | $ | (16,395 | )
Amount of gain (loss) included in earnings attributable to the change in unrealized losses relating to assets and liabilities held at September 30, | $ | 365 |  | $ | (371 | )
Change in Level 3 Fair Value Measurements during the nine months ended September 30,
| Derivative liabilities - net
| 2013 | 2012
Beginning balance, January 1, | $ | (16,539 | ) | $ | (14,760 | )
Total gain (loss) included in earnings | 16,131 |  | (1,529 | )
Settlements | — |  | (106 | )
Ending balance, September 30, | $ | (408 | ) | $ | (16,395 | )
Amount of gain (loss) included in earnings attributable to the change in unrealized losses relating to assets and liabilities held at September 30, | $ | 16,131 |  | $ | (1,529 | )

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- Definition Tabular disclosure of liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, by class that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). Where the quoted price in an active market for the identical liability is not available, the Level 1 input is the quoted price of an identical liability when traded as an asset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19190-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a),(b) -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258 + Details
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- Definition Tabular disclosure of assets and liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19190-110258 + Details
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