| Scheduled Maturities of Time Deposits | The scheduled maturities of time deposits are as follows for the periods indicated:   
        
         |  |  |  |  |  |  |  |  |  |  |  |  |  |  
         |   |   | TimeDeposits More
 Than $250,000
 |   |   | Other TimeDeposits
 |   |   | Total |   |  
         |   |   | (in thousands) |   |  
         | At March 31, 2025 |   |   |   |   |   |   |   |   |   |  
         | 2025 |   | $ | 905,111 |   |   | $ | 988,417 |   |   | $ | 1,893,528 |   |  
         | 2026 |   |   | 204,198 |   |   |   | 235,674 |   |   |   | 439,872 |   |  
         | 2027 |   |   | — |   |   |   | 54,479 |   |   |   | 54,479 |   |  
         | 2028 |   |   | — |   |   |   | 9,941 |   |   |   | 9,941 |   |  
         | 2029 and thereafter |   |   | — |   |   |   | 257 |   |   |   | 257 |   |  
         | Total |   | $ | 1,109,309 |   |   | $ | 1,288,768 |   |   | $ | 2,398,077 |   |  
         |   |   |   |   |   |   |   |   |   |   |  
         | At December 31, 2024 |   |   |   |   |   |   |   |   |   |  
         | 2025 |   | $ | 1,002,785 |   |   | $ | 1,254,185 |   |   | $ | 2,256,970 |   |  
         | 2026 |   |   | 264 |   |   |   | 19,112 |   |   |   | 19,376 |   |  
         | 2027 |   |   | — |   |   |   | 48,630 |   |   |   | 48,630 |   |  
         | 2028 |   |   | — |   |   |   | 130 |   |   |   | 130 |   |  
         | 2029 and thereafter |   |   | — |   |   |   | 177 |   |   |   | 177 |   |  
         | Total |   | $ | 1,003,049 |   |   | $ | 1,322,234 |   |   | $ | 2,325,283 |   |  |