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Financial risk management - interest-bearing financial liabilities (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017
Disclosure of financial instruments by type of interest rate [line items] |  |
Obligations under finance leases | $ 66,471 | $ 82,633
Debt instruments | 352,594 | 350,270
Other financial liabilities | 32,788 | 49,011
Additional borrowing cost if 1% increase in floating interest rate | 1,425 | 161
Interest rate risk |  |
Disclosure of financial instruments by type of interest rate [line items] |  |
Bank borrowings | 141,012 | 1,003
Obligations under finance leases | 66,471 | 82,633
Debt instruments | 352,595 | 350,270
Other financial liabilities | 61,849 | 99,391
Interest-bearing financial liabilities | $ 621,927 | $ 533,297
Percentage of exposure to floating interest rate | 31.00% | 83.00%
Increase in floating interest rate, Percentage | 1.00% |
Interest rate risk | Fixed rate |  |
Disclosure of financial instruments by type of interest rate [line items] |  |
Debt instruments | $ 352,595 | $ 350,270
Other financial liabilities | 61,849 | 86,238
Interest-bearing financial liabilities | 414,444 | 436,508
Interest rate risk | Floating rate |  |
Disclosure of financial instruments by type of interest rate [line items] |  |
Bank borrowings | 141,012 | 1,003
Obligations under finance leases | 66,471 | 82,633
Other financial liabilities |  | 13,153
Interest-bearing financial liabilities | $ 207,483 | $ 96,789

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- Definition The amount of instruments issued by the entity that represent indebtedness. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2018-01-01 -Paragraph 55 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_55&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The amount of liabilities related to the entity's leases. Lease is a contract, or part of a contract, that conveys the right to use an underlying asset for a period of time in exchange for consideration. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Note Effective 2019-01-01 -Name IFRS -Number 16 -IssueDate 2018-01-01 -Paragraph 47 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=16&date=2018-03-01&anchor=para_47_b&doctype=Standard -URIDate 2018-03-16 + Details
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