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v3.19.1

Long-term debt - Convertible senior subordinated notes (Details) $ / shares in Units, $ in Thousands |  | 11 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Aug. 23, 2013 USD ($) $ / shares | Nov. 30, 2017 USD ($) | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) | Jan. 01, 2018 USD ($)
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Principal |  |  | $ 479,535 | $ 702,181 |
Deficit |  |  | (547,839) | (610,908) |
Accumulated other comprehensive loss |  |  | 146,153 | 94,294 |
Interest expense, capitalized to mineral property interests |  |  | 0 | 20,052 |
Convertible senior subordinated notes |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Principal |  |  | 0 | 277,650 |
Conversion ratio | 0.2542912 |  |  |  |
Conversion price per share (in usd per share) | $ / shares | $ 3.93 |  |  |  |
Threshold consecutive trading days | 30 days |  |  |  |
Measurement period | 5 days |  |  |  |
Measurement period consecutive trading days | 5 days |  |  |  |
Unrealized (loss) gain on fair value of convertible notes |  |  | (11,000) | 11,000 |
Interest paid |  |  | 8,000 | 8,000 |
Convertible senior subordinated notes | Bottom of range |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Threshold trading days | 20 days |  |  |  |
Percentage of conversion price | 130.00% |  |  |  |
Convertible senior subordinated notes | Top of range |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Product of last reported sales price per common share and conversion rate | 98.00% |  |  |  |
Fekola |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Interest expense, capitalized to mineral property interests |  | $ 20,000 |  |  |
Fekola | Convertible senior subordinated notes |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Interest expense, capitalized to mineral property interests |  |  | 12,000 |  |
Fixed interest rate | Convertible senior subordinated notes |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Borrowings, interest rate | 3.25% |  |  |  |
Principal | Convertible senior subordinated notes |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Principal | $ 259,000 |  | $ 0 | $ 258,750 |
Increase (decrease) due to changes in accounting policy required by IFRSs | IFRS 9 |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Deficit |  |  |  |  | $ 46,000
Accumulated other comprehensive loss |  |  |  |  | 46,000
Increase (decrease) due to changes in accounting policy required by IFRSs | Convertible senior subordinated notes | IFRS 9 |  |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |  |
Deficit |  |  |  |  | 11,000
Accumulated other comprehensive loss |  |  |  |  | $ 11,000

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