Income taxes (Significant components of unrecognized deferred tax assets) (Details) - CAD ($) $ in Thousands |
Dec. 31, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Disclosure of temporary difference, unused tax losses and unused tax credits [line items] | ||
| Unrecognized deferred tax assets | $ 602,105 | $ 626,453 |
| Income tax losses [Member] | ||
| Disclosure of temporary difference, unused tax losses and unused tax credits [line items] | ||
| Unrecognized deferred tax assets | 394,462 | 379,695 |
| Property, plant and equipment [Member] | ||
| Disclosure of temporary difference, unused tax losses and unused tax credits [line items] | ||
| Unrecognized deferred tax assets | 2,386 | 2,496 |
| Provision for reclamation [Member] | ||
| Disclosure of temporary difference, unused tax losses and unused tax credits [line items] | ||
| Unrecognized deferred tax assets | 81,752 | 81,984 |
| Long-term investments and other, deferred tax assets [Member] | ||
| Disclosure of temporary difference, unused tax losses and unused tax credits [line items] | ||
| Unrecognized deferred tax assets | $ 123,505 | $ 162,278 |