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Financial Instruments and Risk Management (Fair Value And Presentation in the Balance Sheet) (Details) - Derivatives [member] - USD ($) $ in Millions | Dec. 31, 2020 | Dec. 31, 2019
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Disclosure of detailed information about financial instruments [line items] |  |
Financial assets, at fair value |  | $ 3.3
Financial liabilities, at fair value | $ 4.4 |
Currency Hedging Derivative Instruments [Member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Financial assets, at fair value |  | 3.3
Financial liabilities, at fair value | 4.3 |
Fuel Options [Member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Financial assets, at fair value |  | 0.0
Financial liabilities, at fair value | 0.1 |
Gold Options [Member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Financial assets, at fair value |  | $ (0.7)
Financial liabilities, at fair value | $ 0.0 |

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- Definition The fair value of financial assets. [Refer: At fair value [member]; Financial assets] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2020-01-01 -Paragraph 25 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_25&doctype=Standard -URIDate 2020-01-01 + Details
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