Available-for-sale debt securities - Narrative (Details) - USD ($) $ in Millions |
Sep. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Investments, Debt and Equity Securities [Abstract] | ||
| Interest receivable | $ 4.7 | $ 0.9 |
| Aggregate fair value of available-for-sale debt securities in an unrealized loss position | $ 770.2 | $ 9.6 |
| X | ||||||||||
- Definition Amount, after allowance for credit loss, of accrued interest on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- References No definition available.
|