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Financial risk management - Changes in liabilities (Details) - USD ($) $ in Thousands |  | 12 Months Ended
--- | --- | ---
Nov. 07, 2018 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Changes in liabilities arising from financing activities [abstract] |  |  |  |
Beginning of period |  | $ 571,337 | $ 514,587 |
Reclassification of business held for sale |  |  | 86,959 |
Changes from financing cash flows |  | 94,737 | (103,868) |
Effect of changes in foreign exchange rates |  | (10,109) | 26,541 |
Changes in fair value |  | (12,841) | 31,614 |
Other changes |  | 2,265 | 15,504 |
End of period |  | 645,389 | 571,337 | $ 514,587
Dividends paid |  | (20,642) |  | (54,988)
Proceeds from stock option exercises |  | 240 | 180 |
Other amounts paid due to financing activities |  | (932) | (9,709) |
Payments to acquire or redeem own shares | $ (20,100) | (20,100) |  |
Cash flows from (used in) financing activities |  | 53,303 | (113,397) | 49,917
Bank borrowings. |  |  |  |
Changes in liabilities arising from financing activities [abstract] |  |  |  |
Beginning of period |  | 1,003 | 421,291 |
Changes from financing cash flows |  | 140,781 | (426,641) |
Effect of changes in foreign exchange rates |  | (772) | 1,916 |
Other changes |  |  | 4,437 |
End of period |  | 141,012 | 1,003 | 421,291
Obligations under finance leases. |  |  |  |
Changes in liabilities arising from financing activities [abstract] |  |  |  |
Beginning of period |  | 82,633 | 5,237 |
Reclassification of business held for sale |  |  | 81,383 |
Changes from financing cash flows |  | (12,948) | (14,610) |
Effect of changes in foreign exchange rates |  | (3,214) | 10,623 |
End of period |  | 66,471 | 82,633 | 5,237
Debt instruments |  |  |  |
Changes in liabilities arising from financing activities [abstract] |  |  |  |
Beginning of period |  | 350,270 |  |
Changes from financing cash flows |  |  | 337,383 |
Other changes |  | 2,324 | 12,887 |
End of period |  | 352,594 | 350,270 |
Financial loans from government agencies |  |  |  |
Changes in liabilities arising from financing activities [abstract] |  |  |  |
Beginning of period |  | 99,391 | 87,360 |
Changes from financing cash flows |  | (33,096) |  |
Effect of changes in foreign exchange rates |  | (4,446) | 12,031 |
End of period |  | 61,849 | 99,391 | 87,360
Derivative financial instruments |  |  |  |
Changes in liabilities arising from financing activities [abstract] |  |  |  |
Beginning of period |  | 38,040 | 699 |
Reclassification of business held for sale |  |  | 5,576 |
Effect of changes in foreign exchange rates |  | (1,677) | 1,971 |
Changes in fair value |  | (12,841) | 31,614 |
Other changes |  | (59) | (1,820) |
End of period |  | $ 23,463 | $ 38,040 | $ 699

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- Definition The increase (decrease) in liabilities arising from financing activities resulting from the reclassification of business held for sale. + References No definition available. + Details
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- Definition The cash flows from (used in) financing activities, which are activities that result in changes in the size and composition of the contributed equity and borrowings of the entity. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2018-01-01 -Paragraph 10 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2018-03-01&anchor=para_10&doctype=Standard -URIDate 2018-03-16 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2018-01-01 -Paragraph 50 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2018-03-01&anchor=para_50_d&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The increase (decrease) in liabilities arising from financing activities resulting from changes in fair values. [Refer: Liabilities arising from financing activities] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2018-01-01 -Paragraph 44B -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2018-03-01&anchor=para_44B_d&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The increase (decrease) in liabilities arising from financing activities resulting from the effect of changes in foreign exchange rates. [Refer: Liabilities arising from financing activities] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2018-01-01 -Paragraph 44B -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2018-03-01&anchor=para_44B_c&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The increase (decrease) in liabilities arising from financing activities resulting from changes that the entity does not separately disclose in the same statement or note. [Refer: Liabilities arising from financing activities] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2018-01-01 -Paragraph 44B -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2018-03-01&anchor=para_44B_e&doctype=Standard -URIDate 2018-03-16 + Details
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