Note 6 - Loans and the Allowance for Credit Losses (Details Textual) $ in Thousands |
3 Months Ended | ||
|---|---|---|---|
|
Mar. 31, 2026
USD ($)
|
Mar. 31, 2025
USD ($)
|
Dec. 31, 2025
USD ($)
|
|
| Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss | $ 11,582,540 | $ 11,298,975 | |
| Financing Receivable, Number of Modifications | 8 | ||
| Financing Receivable, Modified, Commitment to Lend | $ 0 | $ 0 | |
| Consumer Portfolio Segment [Member] | Periodic Payment Reduction [Member] | |||
| Financing Receivable, Modified, Subsequent Default, Number of Contracts | 0 | 0 | |
| Asset Pledged as Collateral [Member] | Federal Home Loan Bank Advances [Member] | |||
| Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss | $ 8,500,000 | $ 8,200,000 | |