Loans, net and allowance for credit losses - Net Deferred Loan Costs (Details) - USD ($) $ in Thousands |
3 Months Ended | 12 Months Ended |
|---|---|---|
Mar. 31, 2026 |
Dec. 31, 2025 |
|
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Net deferred loan costs | $ 2,100 | $ 1,900 |
| Unearned income | 1,500 | 1,500 |
| Net unaccreted discounts | 39,600 | 42,700 |
| Net loans | 4,150,616 | $ 4,027,889 |
| Federal Home Loan Bank (FHLB) | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Amount of credit facility used to issue standby letters of credit to collateralize public fund deposits | $ 452,300 |