Note 5 - Derivative and Other Hedging Instruments - Schedule of Interest Rate Swaps (Details) - Interest Rate Swap [Member] - USD ($) $ in Millions |
9 Months Ended | 12 Months Ended |
|---|---|---|
Sep. 30, 2026 |
Dec. 31, 2025 |
|
| Notional amount | $ 7,864.2 | $ 5,858.3 |
| Average fixed pay rate | 3.63% | 3.53% |
| Average receive rate | 3.90% | 3.87% |
| Average maturity (Year) | 4 years 8 months 12 days | 4 years 3 months 18 days |
| One to Five Years [Member] | ||
| Notional amount | $ 5,292.8 | $ 4,162.5 |
| Average fixed pay rate | 3.47% | 3.38% |
| Average receive rate | 3.90% | 3.87% |
| Average maturity (Year) | 2 years 10 months 24 days | 3 years 2 months 12 days |
| More Than Five Years [Member] | ||
| Notional amount | $ 2,571.4 | $ 1,695.8 |
| Average fixed pay rate | 3.97% | 3.87% |
| Average receive rate | 3.90% | 3.87% |
| Average maturity (Year) | 8 years 3 months 18 days | 7 years 1 month 6 days |