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Provisions - Employee obligations - Venezuela - (Details) $ in Thousands | 12 Months Ended
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Dec. 31, 2018 USD ($) age | Dec. 31, 2017 USD ($) age
Venezuela |  |
Actuarial Assumptions Used To Calculate Defined Benefit Obligation [Abstract] |  |
Salary increase | 400000.00% | 207.25%
Discount rate | 520004.00% | 219.54%
Expected inflation rate | 500000.00% | 207.00%
Retirement age | age | 64 | 63
France |  |
Actuarial Assumptions Used To Calculate Defined Benefit Obligation [Abstract] |  |
Discount rate | 2.00% | 2.00%
Expected inflation rate | 1.60% | 1.60%
Retirement age | age | 65 | 65
France | Minimum |  |
Actuarial Assumptions Used To Calculate Defined Benefit Obligation [Abstract] |  |
Salary increase | 1.60% | 1.60%
France | Maximum |  |
Actuarial Assumptions Used To Calculate Defined Benefit Obligation [Abstract] |  |
Salary increase | 6.10% | 6.10%
South Africa |  |
Actuarial Assumptions Used To Calculate Defined Benefit Obligation [Abstract] |  |
Salary increase | 7.20% | 8.10%
Discount rate | 9.90% | 10.30%
Expected inflation rate | 6.20% | 7.10%
Retirement age | age | 63 | 63
FerroAtlantica De Venezuela SA | Venezuela |  |
Disclosure of defined benefit plans [line items] |  |
Years of service | 15 years |
Percentage of basic salary guaranteed by IVSS | 80 |
Present value of defined benefit obligation [member] | South Africa |  |
Changes in net defined benefit liability (asset) [abstract] |  |
Obligations at beginning of year | $ 7,872 | $ 8,760
Current service cost | 139 | 310
Borrowing costs | 740 | 932
Actuarial differences | 2,000 | 2,226
Benefits paid | 226 | 740
Exchange differences | (1,096) | 836
Obligations at end of year | 5,429 | 7,872
Present value of defined benefit obligation [member] | FerroAtlantica De Venezuela SA | Venezuela |  |
Changes in net defined benefit liability (asset) [abstract] |  |
Obligations at beginning of year | 1,883 | 2,955
Current service cost | 775 | 158
Borrowing costs |  | 2,255
Benefits paid | (35) | (93)
Exchange differences | (2,089) | (3,392)
Obligations at end of year | $ 534 | $ 1,883

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- Definition Represents the number of years of service at the company accumulated by the employee + References No definition available. + Details
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- Definition The discount rate used as the significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 144 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_144&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The expected rate of inflation that is used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit plans [member]; Defined benefit obligation, at present value; Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 144 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_144&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from employee service in the current period. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 141 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_141_a&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The decrease (increase) in a net defined benefit liability (asset) resulting from the remeasurement of that net defined benefit liability (asset). [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 141 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_141_c&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from changes in foreign exchange rates. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 141 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_141_e&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from the passage of time. [Refer: Interest expense; Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 141 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_141_b&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The amount of deficit or surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 140 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_140_a&doctype=Standard -URIDate 2018-03-16 + Details
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