Short-term investments (Details) - USD ($) $ in Thousands |
Dec. 31, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Investment [Line Items] | ||
| Short-term investments | $ 756,543 | $ 580,026 |
| Unrestricted | ||
| Investment [Line Items] | ||
| Short-term investments | 688,796 | 489,596 |
| Affected by drawing restrictions related to minimum reserve and derivative margin requirements | ||
| Investment [Line Items] | ||
| Short-term investments | 67,747 | 90,430 |
| Affected by drawing restrictions related to minimum reserve and derivative margin requirements | Interest earning demand and term deposits | ||
| Investment [Line Items] | ||
| Short-term investments | 67,747 | 90,430 |
| Maturing within three months | Unrestricted | ||
| Investment [Line Items] | ||
| Short-term investments | 321,566 | 415,072 |
| Maturing between three to six months | Unrestricted | ||
| Investment [Line Items] | ||
| Short-term investments | 223,239 | 74,524 |
| Maturing between six to twelve months | Unrestricted | ||
| Investment [Line Items] | ||
| Short-term investments | $ 143,991 | $ 0 |