| Scheduled Maturities of Time Deposits | The scheduled maturities of time deposits are as follows for the periods indicated:   
       
        |  |  |  |  |  |  |  |  |  |  |  |  |  |  
        | At September 30, 2023 |   | TimeDeposits Greater
 Than $250,000
 |   |   | Other TimeDeposits
 |   |   | Total |   |  
        |   |   | (in thousands) |   |  
        | 2023 |   | $ | 432,361 |   |   | $ | 540,642 |   |   | $ | 973,003 |   |  
        | 2024 |   |   | 597,364 |   |   |   | 855,244 |   |   |   | 1,452,608 |   |  
        | 2025 |   |   | 266 |   |   |   | 4,803 |   |   |   | 5,069 |   |  
        | 2026 |   |   | 263 |   |   |   | 2,870 |   |   |   | 3,133 |   |  
        | 2027 and thereafter |   |   | — |   |   |   | 882 |   |   |   | 882 |   |  
        | Total |   | $ | 1,030,254 |   |   | $ | 1,404,441 |   |   | $ | 2,434,695 |   |  
        |   |   |   |   |   |   |   |   |   |   |  
        | At December 31, 2022 |   |   |   |   |   |   |   |   |   |  
        | 2023 |   | $ | 696,470 |   |   | $ | 1,185,020 |   |   | $ | 1,881,490 |   |  
        | 2024 |   |   | — |   |   |   | 68,037 |   |   |   | 68,037 |   |  
        | 2025 |   |   | 266 |   |   |   | 3,151 |   |   |   | 3,417 |   |  
        | 2026 |   |   | 263 |   |   |   | 2,430 |   |   |   | 2,693 |   |  
        | 2027 and thereafter |   |   | — |   |   |   | 570 |   |   |   | 570 |   |  
        | Total |   | $ | 696,999 |   |   | $ | 1,259,208 |   |   | $ | 1,956,207 |   |  |