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Financial Instruments and Risk Management (Financial Instruments and Related Risks Narrative) (Details) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 USD ($) $ / oz oz | Dec. 31, 2023 USD ($)
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Average realized price per ounce | $ / oz | 1,950 |
Total liabilities | $ (1,751.9) | $ (1,077.7)
Unrealized loss on commodity derivatives | $ 24.2 | 0.9
Average realized price per ounce, fluctuation, percentage | 10.00% |
Gold Forward Contracts | Level 2 |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Total liabilities | $ (140.0) | 0.0
Gold Options | Argonaut |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Increase or decrease due to change in fair value of forward contracts | 39.4 |
Gold Options | Derivatives |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Financial liabilities, at fair value | $ 0.0 |
Gold Forward Contracts | 2026 |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Ounces subject to contract | oz | 100,000 |
Gold Forward Contracts | 2027 |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Ounces subject to contract | oz | 50,000 |
Interest rate risk |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Impact on interest earned | $ 1.5 |
Borrowings, adjustment to interest rate basis | 1.00% |
Currency risk |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Potential percentage change in value | 10.00% |
Market risk | Gold Options | Argonaut |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Average realized price per ounce | $ / oz | 2,629 |
Market risk | Gold Options | Bottom of range |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Average realized price per ounce | $ / oz | 1,992 |
Market risk | Gold Options | Top of range |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Average realized price per ounce | $ / oz | 2,787 |
Commodity price risk | Gold Options |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Unrealized loss on commodity derivatives | $ (9.3) | (0.1)
Fair value adjustment on contingent consideration | $ 24.2 | 0.9
Commodity price risk | Gold Options | Argonaut |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Fair value adjustment on contingent consideration |  | $ 25.0
Commodity price risk | Gold Forward Contracts | Purchase Put Options |  |
Disclosure of nature and extent of risks arising from financial instruments [line items] |  |
Average realized price per ounce | $ / oz | 1,821 |

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