Segmented information (Schedule of segments, additions to property, plant and equipment) (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Disclosure of operating segments [line items] | ||
| Additions to property, plant and equipment | $ 582.5 | $ 486.2 |
| Peru [Member] | ||
| Disclosure of operating segments [line items] | ||
| Additions to property, plant and equipment | 207.0 | 177.8 |
| Manitoba [Member] | ||
| Disclosure of operating segments [line items] | ||
| Additions to property, plant and equipment | 64.9 | 63.3 |
| British Columbia [Member] | ||
| Disclosure of operating segments [line items] | ||
| Additions to property, plant and equipment | 228.1 | 214.9 |
| Arizona [Member] | ||
| Disclosure of operating segments [line items] | ||
| Additions to property, plant and equipment | 82.2 | 30.2 |
| Corporate and other activities [Member] | ||
| Disclosure of operating segments [line items] | ||
| Additions to property, plant and equipment | $ 0.3 | $ 0.0 |