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Debt (Details) - USD ($) $ in Millions | 9 Months Ended |  |
--- | --- | --- | ---
Sep. 30, 2019 | Dec. 31, 2018 | Jun. 04, 2013
Debt Instrument [Line Items] |  |  |
Term loan - current portion, interest payable monthly | $ 15.0 | $ 0.0 |
Hancock County industrial revenue bonds (IRBs) due 2028, interest payable quarterly (variable interest rates (not to exceed 12%)) (1) | 7.8 | 7.8 |
Term loan - less current portion, interest payable monthly | 25.0 | 0.0 |
Total debt | 297.2 | 279.7 |
Hawesville [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Term loan - current portion, interest payable monthly | 15.0 | 0.0 |
Term loan - less current portion, interest payable monthly | 25.0 | 0.0 |
Long-term Debt [Member] | Senior secured notes due June 01, 2021 [Member] |  |  |
Debt Instrument [Line Items] |  |  |
7.5% senior secured notes due June 1, 2021, net of debt discount of $1.0 million and $1.4 million, respectively, interest payable semiannually | $ 249.0 | 248.6 |
Maturity date | Jun. 01, 2021 |  |
Stated interest rate, percentage | 7.50% |  | 7.50%
Debt discount | $ 1.0 | 1.4 |
Short-term Debt [Member] | Industrial revenue bonds due 2028 [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Hancock County industrial revenue bonds (IRBs) due 2028, interest payable quarterly (variable interest rates (not to exceed 12%)) (1) | $ 7.8 | 7.8 |
Maturity date | Apr. 01, 2028 |  |
Stated interest rate, percentage | 1.77% |  |
Short-term Debt [Member] | Industrial revenue bonds due 2028 [Member] | Maximum [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Effective interest rate, maximum | 12.00% |  |
Short-term Debt [Member] | Revolving Credit Facility, Portion Subject To Base Rate [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Line of credit facility, interest rate at period end | 5.25% |  |
Short-term Debt [Member] | U.S. revolving credit facility borrowings [Member] |  |  |
Debt Instrument [Line Items] |  |  |
U.S revolving credit facility | $ 0.4 | $ 23.3 |
Stated interest rate, percentage | 5.375% |  |
Short-term Debt [Member] | U.S. revolving credit facility borrowings [Member] | Revolving Credit Facility, Portion Subject To LIBOR Rate [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Stated interest rate, percentage | 2.16% |  |

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- Definition Carrying value as of the balance sheet date of the long-term debt associated with industrial revenue bonds. For classified balance sheets, these bonds are considered current assets because they are remarketed weekly and the bonds could be required to be repaid upon demand if there is a failed remarketing. + References No definition available. + Details
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