| Line Item | Dec 31, 2025 | Dec 31, 2024 | Dec 31, 2023 | Dec 31, 2022 | Dec 31, 2021 | Dec 31, 2020 | Dec 31, 2019 | Dec 31, 2018 |
|---|---|---|---|---|---|---|---|---|
| Profit or loss [abstract] | ||||||||
| Sales | ||||||||
| Cost of sales | ||||||||
| Mine operating income | ||||||||
| Other expenses | ||||||||
| General and administration | ||||||||
| Foreign exchange loss | ||||||||
| Reversal of impairment of mineral properties, plant and equipment | ||||||||
| Write-off of mineral properties | ||||||||
| Other expenses | ||||||||
| Operating expenses (income), total | ||||||||
| Operating income | ||||||||
| Other income (loss) | ||||||||
| Investment gains | ||||||||
| Interest and finance costs, net | ||||||||
| Gain on derivatives | ||||||||
| Financial income (expense), total | ||||||||
| Income before income taxes | ||||||||
| Income taxes | ||||||||
| Current income tax expense | ||||||||
| Deferred income tax recovery | ||||||||
| Total tax expense | ||||||||
| Net income from continuing operations | ||||||||
| Net income from discontinued operations, net of tax | ||||||||
| Net income | ||||||||
| Net income from continuing operations attributable to: | ||||||||
| Non-controlling interests | ||||||||
| Net income attributable to: | ||||||||
| Fortuna shareholders | ||||||||
| Non-controlling interests |