Exploration and evaluation assets - Schedule of exploration and evaluation asset (Parenthetical) (Detail) - USD ($) |
12 Months Ended | ||||||
|---|---|---|---|---|---|---|---|
Nov. 01, 2024 |
Dec. 31, 2025 |
Dec. 31, 2024 |
|||||
| Exploration and evaluation assets [member] | |||||||
| Schedule of exploration and evaluation assets [Line Items] | |||||||
| Proceeds from royalty option agreement | $ 1,000,000 | $ 0 | [1] | $ 1,000,000 | [1] | ||
| |||||||