v3.26.1
Financial Instruments - Estimated Fair Values of Financial Instruments (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Financial assets:    
Fed funds sold $ 6,025 $ 3,000
Investment securities - held-to-maturity 1,144,994 1,161,052
Carrying Amount    
Financial assets:    
Cash and cash equivalents 1,111,923 667,337
Fed funds sold 6,025 3,000
Investment securities - held-to-maturity 1,256,635 1,259,262
Loans receivable, net of impaired loans and allowance 15,132,724 15,186,203
Accrued interest receivable 106,628 108,939
FHLB, Federal Reserve & FNBB stock; other equity investments 224,354 225,288
Marketable equity securities 52,673 53,921
Financial liabilities:    
Demand and non-interest bearing 3,994,217 3,868,405
Savings and interest-bearing transaction accounts 11,971,866 11,792,828
Time deposits 1,772,192 1,818,724
Securities sold under agreements to repurchase 157,409 155,803
FHLB and other borrowed funds 500,250 500,250
Accrued interest payable 12,346 14,868
Subordinated debentures 279,433 279,265
Fair Value Measurements    
Financial assets:    
Cash and cash equivalents 1,111,923 667,337
Fed funds sold 6,025 3,000
Investment securities - held-to-maturity 1,144,994 1,161,052
Loans receivable, net of impaired loans and allowance 15,150,428 15,205,769
Accrued interest receivable 106,628 108,939
FHLB, Federal Reserve & FNBB stock; other equity investments 224,354 225,288
Marketable equity securities 52,673 53,921
Financial liabilities:    
Demand and non-interest bearing 3,994,217 3,868,405
Savings and interest-bearing transaction accounts 11,971,866 11,792,828
Time deposits 1,758,751 1,807,002
Securities sold under agreements to repurchase 157,409 155,803
FHLB and other borrowed funds 469,595 474,663
Accrued interest payable 12,346 14,868
Subordinated debentures 268,116 265,170
Level 1 | Fair Value Measurements    
Financial assets:    
Cash and cash equivalents 1,111,923 667,337
Fed funds sold 6,025 3,000
Investment securities - held-to-maturity 27,255 27,457
Loans receivable, net of impaired loans and allowance 0 0
Accrued interest receivable 106,628 108,939
FHLB, Federal Reserve & FNBB stock; other equity investments 0 0
Marketable equity securities 52,673 53,921
Financial liabilities:    
Demand and non-interest bearing 3,994,217 3,868,405
Savings and interest-bearing transaction accounts 11,971,866 11,792,828
Time deposits 0 0
Securities sold under agreements to repurchase 157,409 155,803
FHLB and other borrowed funds 0 0
Accrued interest payable 12,346 14,868
Subordinated debentures 0 0
Level 2 | Fair Value Measurements    
Financial assets:    
Cash and cash equivalents 0 0
Fed funds sold 0 0
Investment securities - held-to-maturity 1,117,739 1,133,595
Loans receivable, net of impaired loans and allowance 0 0
Accrued interest receivable 0 0
FHLB, Federal Reserve & FNBB stock; other equity investments 0 0
Marketable equity securities 0 0
Financial liabilities:    
Demand and non-interest bearing 0 0
Savings and interest-bearing transaction accounts 0 0
Time deposits 0 0
Securities sold under agreements to repurchase 0 0
FHLB and other borrowed funds 469,595 474,663
Accrued interest payable 0 0
Subordinated debentures 0 0
Level 3 | Fair Value Measurements    
Financial assets:    
Cash and cash equivalents 0 0
Fed funds sold 0 0
Investment securities - held-to-maturity 0 0
Loans receivable, net of impaired loans and allowance 15,150,428 15,205,769
Accrued interest receivable 0 0
FHLB, Federal Reserve & FNBB stock; other equity investments 224,354 225,288
Marketable equity securities 0 0
Financial liabilities:    
Demand and non-interest bearing 0 0
Savings and interest-bearing transaction accounts 0 0
Time deposits 1,758,751 1,807,002
Securities sold under agreements to repurchase 0 0
FHLB and other borrowed funds 0 0
Accrued interest payable 0 0
Subordinated debentures $ 268,116 $ 265,170