Allowance for Credit Losses - Non-accrual Basis By Loan Class (Details) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
Loan loss allowances, financing receivable past due
Non-accrual loans, total	$ 337,080	$ 140,302
Non-accrual loans with no credit allowance	202,144	78,654
Commercial, financial and agricultural \| Domestic \| Commercial
Loan loss allowances, financing receivable past due
Non-accrual loans, total	240,548	52,397
Non-accrual loans with no credit allowance	172,406	51,513
Commercial, financial and agricultural \| Domestic \| Commercial real estate: farmland & commercial
Loan loss allowances, financing receivable past due
Non-accrual loans, total	42,005	45,066
Non-accrual loans with no credit allowance	20,449	22,003
Commercial, financial and agricultural \| Domestic \| Commercial real estate: multifamily
Loan loss allowances, financing receivable past due
Non-accrual loans, total	50,942	42,787
Non-accrual loans with no credit allowance	9,034	5,086
Commercial real estate \| Domestic \| Commercial real estate construction development
Loan loss allowances, financing receivable past due
Non-accrual loans, total	3,516
Non-accrual loans with no credit allowance	186
Real estate - mortgage \| Domestic \| Residential First Lien
Loan loss allowances, financing receivable past due
Non-accrual loans, total	69	52
Non-accrual loans with no credit allowance	$ 69	$ 52