Note 5 - Derivatives 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, 2023	Dec. 31, 2022
Notional Amount	$ 2,626.5	$ 1,400.0
Average fixed pay rate	2.46%	1.39%
Average receive rate	5.31%	4.41%
Average maturity (Year)	6 years 7 months 6 days	5 years 7 months 6 days
One to Five Years [Member]
Notional Amount	$ 500.0	$ 500.0
Average fixed pay rate	0.84%	0.84%
Average receive rate	5.31%	4.75%
Average maturity (Year)	3 years	3 years 8 months 12 days
More Than Five Years [Member]
Notional Amount	$ 2,126.5	$ 900.0
Average fixed pay rate	2.84%	1.70%
Average receive rate	5.31%	4.23%
Average maturity (Year)	7 years 4 months 24 days	6 years 7 months 6 days