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Debt instruments (Details) - USD ($) $ in Thousands | Feb. 15, 2017 | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | --- | ---
Debt Instruments |  |  |
Amount due for settlement within 12 months |  | $ 10,937 | $ 10,938
Amount due for settlement after 12 months |  | 341,657 | 339,332
Total debt instruments |  | 352,594 | 350,270
Senior Notes due 2022 |  |  |
Debt Instruments |  |  |
Principal amount | $ 350,000 | 350,000 | 350,000
Unamortised issuance costs |  | (8,343) | (10,668)
Accrued coupon interest |  | 10,937 | 10,938
Issuance costs | $ 12,116 |  |
Amount due for settlement within 12 months |  | 10,937 | 10,938
Amount due for settlement after 12 months |  | 341,657 | 339,332
Total debt instruments |  | 352,594 | 350,270
Fixed Interest Rate | 9.375% |  |
Redemption price of notes | 109.375% |  |
Redemption price of notes at change of control | 101.00% |  |
Fair value of notes payable |  | $ 288,022 | $ 378,000
Senior Notes due 2022 issued by Ferroglobe PLC |  |  |
Debt Instruments |  |  |
Principal amount | $ 150,000 |  |
Senior Notes due 2022 issued by Globe Specialty Metals, Inc |  |  |
Debt Instruments |  |  |
Principal amount | $ 200,000 |  |
Maximum | Senior Notes due 2022 |  |  |
Debt Instruments |  |  |
Potential redemption of notes as a percentage of aggregate principal amount | 35.00% |  |
Grupo Villar Mir, S.A.U. |  |  |
Debt Instruments |  |  |
Ownership interest as a percentage | 53.90% |  |

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- Definition Percentage price of original principal amount of debt at which the debt is required to be redeemed in the event of a change in control. + References No definition available. + Details
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- Definition Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs. + References No definition available. + Details
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