v3.25.3
COMMITMENTS AND CONTINGENCIES - Additional Information (Details) - USD ($)
$ in Thousands
9 Months Ended 12 Months Ended
Sep. 30, 2025
Dec. 31, 2024
Jun. 30, 2025
Sep. 30, 2024
Jun. 30, 2024
Jan. 01, 2024
Dec. 31, 2023
Commitments and Contingencies Disclosure [Line Items]              
Reserves for unfunded commitments $ 17,600 $ 16,900          
Loans and Leases Receivable, Commitments, Fixed Rates 71,100 69,300          
Loans and Leases Receivable, Commitments, Variable Rates $ 4,000,000 $ 3,700,000          
Loan Commitments, Fixed Interest Rate Range, Minimum 0.00% 0.00%          
Loan Commitments, Fixed Interest Rate Range, Maximum 21.00% 21.00%          
Loan Commitments, Fixed Rate, Maturities, Minimum 1 year 1 year          
Loan Commitments, Fixed Rate, Maturities, Maximum 31 years 31 years 7 months 6 days          
Letters of credit issued to guarantee performance of a client to a third party $ 26,500 $ 25,100          
Derivative, Notional Amount 20,507,545 16,941,027          
Stockholders' Equity Attributable to Parent 2,631,855 2,438,041 $ 2,558,155 $ 2,450,438 $ 2,326,439   $ 2,267,974
Estimated Litigation Liability 0 0          
Retained earnings              
Commitments and Contingencies Disclosure [Line Items]              
Stockholders' Equity Attributable to Parent 1,399,577 1,276,329 $ 1,351,674 $ 1,234,375 $ 1,204,844   $ 1,136,718
Cumulative Effect, Period of Adoption, Adjustment [Member] | Retained earnings              
Commitments and Contingencies Disclosure [Line Items]              
Stockholders' Equity Attributable to Parent           $ 600  
Credit Default Swap              
Commitments and Contingencies Disclosure [Line Items]              
Derivative, Notional Amount 298,200 310,700          
Commitments to Extend Credit              
Commitments and Contingencies Disclosure [Line Items]              
Commitments outstanding to extend credit $ 4,100,000 $ 3,800,000