Note 14 - Financial Derivatives - Cash Flow Swap Hedges (Details) - USD ($)		3 Months Ended		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Net change in unrealized holding loss on cash flow hedge derivatives		$ (441,000)	$ (441,000)
Fair Value Hedging [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Notional		$ 775,466,000		$ 1,156,007,000
Weighted average fixed rate-pay		2.87%		2.01%
Weighted average variable rate spread		0.22%		0.32%
Weighted average variable rate-receive		5.56%		5.41%
Net change in unrealized holding loss on cash flow hedge derivatives	[1]	$ 11,502		$ 7,935
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Notional		42,000,000		38,600,000
Periodic net settlement of swaps	[2]	$ 6,841,000		$ 6,336,000

[1] the amount is included in other non-interest income.

[2] the amount of periodic net settlement of interest rate swaps was included in interest income.