Investment in securities - Pledged Investments (Details) - USD ($) $ in Thousands |
Dec. 31, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Financial Instruments Owned and Pledged as Collateral [Line Items] | ||
| Available-for-sale, amortized cost | $ 2,785,608 | $ 2,435,752 |
| Available-for-sale, fair value | 2,696,253 | 2,272,486 |
| Held-to-maturity, amortized cost | 2,992,052 | 3,240,290 |
| Held-to-maturity, fair value | 2,566,470 | 2,671,040 |
| Non-US governments debt securities | ||
| Financial Instruments Owned and Pledged as Collateral [Line Items] | ||
| Available-for-sale, amortized cost | 0 | 93,803 |
| Available-for-sale, fair value | 0 | 93,468 |
| Asset Pledged as Collateral with Right | ||
| Financial Instruments Owned and Pledged as Collateral [Line Items] | ||
| Available-for-sale, amortized cost | 19,184 | 22,888 |
| Available-for-sale, fair value | 18,331 | 21,062 |
| Held-to-maturity, amortized cost | 96,811 | 95,588 |
| Held-to-maturity, fair value | $ 87,154 | $ 84,003 |
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- Definition Amortized cost excluding accrued interest, after allowance for credit loss, of 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/2009/role/commonPracticeRef
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- Definition Amount excluding accrued interest, of 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/2009/role/commonPracticeRef
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- Definition Amount excluding accrued interest, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Fair value of investment in debt security measured at amortized cost (held-to-maturity). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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