Note 6 - Other Long-term Debt - Summary of Other Long-term Debt (Details) (Parentheticals) |
3 Months Ended | 6 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Mar. 31, 2024 |
Jun. 30, 2025 |
Dec. 31, 2024 |
Jan. 31, 2022 |
Jun. 30, 2020 |
|
| Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration] | Secured Overnight Financing Rate (SOFR) [Member] | Secured Overnight Financing Rate (SOFR) [Member] | Secured Overnight Financing Rate (SOFR) [Member] | ||
| 5.50% Subordinated Notes Due in 2030 [Member] | |||||
| Debt instrument, fixed interest rate | 5.50% | 5.50% | 5.50% | ||
| Debt instrument, maturity year | 2030 | 2030 | |||
| 3.50% Subordinated Notes Due in 2032 [Member] | |||||
| Debt instrument, fixed interest rate | 3.50% | 3.50% | 3.50% | ||
| Debt instrument, maturity year | 2032 | 2032 | |||
| Variable Interest Rate Subordinated Debentures Due in 2035 [Member] | |||||
| Debt instrument, maturity year | 2035 | 2035 | |||
| Debt instrument, variable interest rate | 1.68% | 1.68% |