This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Amount of direct write-downs of financing receivables charged against the allowance.

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The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale.

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

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The aggregate amount provided for estimated restructuring charges, remediation costs, and asset impairment loss during an accounting period. Generally, these items are either unusual or infrequent, but not both (in which case they would be extraordinary items).

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Impairment Charges (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended		3 Months Ended
Impairment Charges (Narrative) (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Jun. 30, 2013 Tenaska Trailblazer Partners, LLC [Member]	Mar. 31, 2013 Tenaska Trailblazer Partners, LLC [Member]	Sep. 30, 2013 DKRW Advanced Fuels, LLC [Member]	Jun. 30, 2013 DKRW Advanced Fuels, LLC [Member]
Restructuring Cost and Reserve [Line Items]
Impairment and closure charges	$ 5,060,000	$ 200,397,000	$ 6,572,000	$ 220,879,000	$ 20,500,000		$ 57,700,000
Impairment charges - assets to be disposed of		142,818,000
Equity Method Investment, Ownership Percentage						35.00%		24.00%
Equity Method Investment, Other than Temporary Impairment					15,300,000		13,700,000
Losses on write down of receivable from equity method investee					$ 5,200,000		$ 44,000,000