v3.26.3
FAIR VALUE DISCLOSURES - Estimated Fair Values of Financial Instruments (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Mar. 31, 2026
Sep. 30, 2026
Dec. 31, 2025
Financial assets      
Investment securities held-to-maturity   $ 38,321 $ 58,545
Other Investments   139,535 129,564
Interest Receivable   57,766 54,100
Deposits      
Noninterest-bearing   3,831,099 3,465,470
Savings   6,408,902 5,973,532
Time   3,636,887 3,622,227
Federal Home Loan Bank Stock and Federal Reserve Bank Stock   $ 126,700 116,700
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Discount Rate 11.66% 11.75%  
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Prepayment Speed 6.49% 6.10%  
Impaired Commercial And Commercial Real Estate Loans Member      
Deposits      
Principal Amount of Commercial and Commercial Real Estate Loans   $ 104,800 38,100
Allowance for Loan and Lease Losses, Real Estate   14,900 16,100
Carrying value      
Financial assets      
Cash and interest-bearing deposits with other banks   742,880 775,891
Investment securities held-to-maturity   38,321 58,545
Other Investments   12,842 12,898
Loans and leases   13,713,432 13,237,583
Interest Receivable   81,049 71,940
Deposits      
Deposits   17,697,791 16,421,842
Short-term borrowings   651,860 675,332
Long-term debt   364,925 514,052
Interest Payable   38,293 38,304
Fair value      
Financial assets      
Cash and interest-bearing deposits with other banks   742,880 775,891
Investment securities held-to-maturity   32,900 54,334
Other Investments   12,842 12,898
Loans and leases   13,522,821 13,061,341
Interest Receivable   81,049 71,940
Deposits      
Deposits   17,681,857 16,415,852
Short-term borrowings   651,860 675,332
Long-term debt   306,399 473,291
Interest Payable   38,293 38,304
Fair Value, Inputs, Level 1 [Member] | Fair value      
Financial assets      
Cash and interest-bearing deposits with other banks   742,880 775,891
Investment securities held-to-maturity   0 0
Other Investments   1,794 1,850
Loans and leases   0 0
Interest Receivable   0 0
Deposits      
Deposits   0 0
Short-term borrowings   651,860 675,332
Long-term debt   0 0
Interest Payable   1,581 2,918
Fair Value, Inputs, Level 2 [Member] | Fair value      
Financial assets      
Cash and interest-bearing deposits with other banks   0 0
Investment securities held-to-maturity   32,900 54,334
Other Investments   40 40
Loans and leases   0 0
Interest Receivable   23,283 17,833
Deposits      
Deposits   17,681,857 16,415,852
Short-term borrowings   0 0
Long-term debt   306,399 473,291
Interest Payable   36,712 35,386
Fair Value, Inputs, Level 3 [Member] | Fair value      
Financial assets      
Cash and interest-bearing deposits with other banks   0 0
Investment securities held-to-maturity   0 0
Other Investments   11,008 11,008
Loans and leases   13,522,821 13,061,341
Interest Receivable     54,107
Deposits      
Deposits   0 0
Short-term borrowings   0 0
Long-term debt   0 0
Interest Payable   $ 0 $ 0