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Fair value measurement (Tables) | 12 Months Ended
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Dec. 31, 2018
Disclosure of financial liabilities [abstract] |
Schedule of assets and liabilities measured at fair value |
|  | December 31, 2018
|  |  |  | Quoted prices in active markets |  | Significant observable inputs |  | Significant unobservable inputs
|  | Total |  | (Level 1) |  | (Level 2) |  | (Level 3)
|  | US$'000 |  | US$'000 |  | US$'000 |  | US$'000
Other assets (Note 12): |  |  |  |  |  |  |  |
Biological assets |  | 7,790 |  | — |  | — |  | 7,790
Other financial assets (Note 10): |  |  |  |  |  |  |  |
Debt investments |  | 67,079 |  | — |  | — |  | 67,079
Listed equity securities |  | 2,523 |  | 2,523 |  | — |  | —
Other financial liabilities (Note 19): |  |  |  |  |  |  |  |
Derivative financial instruments - cross currency swap |  | (20,384) |  | — |  | (20,384) |  | —
Derivative financial instruments - interest rate swaps |  | (3,079) |  | — |  | (3,079) |  | —
Other liabilities (Note 21) |  |  |  |  |  |  |  |
Contingent consideration in a business combinations |  | (26,222) |  | — |  | — |  | (26,222)
|  | December 31, 2017
|  |  |  | Quoted prices in active markets |  | Significant observable inputs |  | Significant unobservable inputs
|  | Total |  | (Level 1) |  | (Level 2) |  | (Level 3)
|  | US$'000 |  | US$'000 |  | US$'000 |  | US$'000
Other assets (Note 12): |  |  |  |  |  |  |  |
Biological assets |  | 27,279 |  | — |  | — |  | 27,279
Other financial assets (Note 10): |  |  |  |  |  |  |  |
Other |  | 82,638 |  | — |  | — |  | 82,638
Other financial liabilities (Note 19): |  |  |  |  |  |  |  |
Derivative financial instruments - cross currency swap |  | (33,648) |  | — |  | (33,648) |  | —
Derivative financial instruments - interest rate swaps |  | (4,392) |  | — |  | (4,392) |  | —
Schedule of changes fair value of biological assets classified at level 3 in the hierarchy |
|  | Level 3
|  | US$'000
January 1, 2017 |  | 17,365
Gain recognised in profit or loss (Note 25.5) |  | 7,504
Translation differences |  | 2,410
December 31, 2017 |  | 27,279
Loss recognised in profit or loss (Note 25.5) |  | (7,615)
Disposal of biological assets |  | (12,168)
Translation differences |  | 294
December 31, 2018 |  | 7,790

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