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Long-term power contract for Hawesville (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Long-term power contract for Hawesville [Abstract]
Term of the Big Rivers Agreement	through 2023
Adequate power provided for full production capacity requirements (in megawatts)	482
Realized benefit of contractual receivable		$ 68,794	$ 26,025
Net gain on long-term power delivery contract termination			$ 56,964

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- Definition

The electrical power requirements necessary for full production requirement.

+ References

No definition available.

+ Details

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- Definition

This element represents the income received from or payment made to a third party in connection with the contract receivable between the parties.

+ References

No definition available.

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- Definition

This element represent the expiration date of the contract.

+ References

No definition available.

+ Details

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- Definition

Gain (loss) related to the termination of a contract between the parties. The termination may be due to many causes including early termination of a lease by a lessee, a breach of contract by one party, or a failure to perform.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)(1)

-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

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