Financial commitments and contingent liabilities - Undrawn Commitments (Details) - USD ($) $ in Thousands |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Commitments and Contingencies Disclosure [Abstract] | ||
| Definitive | $ 1,295,753 | $ 1,269,708 |
| Discretionary | 725,669 | 793,533 |
| Legal risk (definitive) | 46,915 | 47,235 |
| Total capital provision undrawn commitments | $ 2,068,337 | $ 2,110,476 |