Note 5 - Derivative and Other Hedging Instruments - Schedule of Interest Rate Swaps (Details) - Interest Rate Swap [Member] - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2026	Dec. 31, 2025
Notional amount	$ 7,014.2	$ 5,858.3
Average fixed pay rate	3.56%	3.53%
Average receive rate	3.68%	3.87%
Average maturity (Year)	4 years 7 months 6 days	4 years 3 months 18 days
One to Five Years [Member]
Notional amount	$ 4,792.8	$ 4,162.5
Average fixed pay rate	3.40%	3.38%
Average receive rate	3.68%	3.87%
Average maturity (Year)	3 years	3 years 2 months 12 days
More Than Five Years [Member]
Notional amount	$ 2,221.4	$ 1,695.8
Average fixed pay rate	3.90%	3.87%
Average receive rate	3.68%	3.87%
Average maturity (Year)	8 years	7 years 1 month 6 days