Note 2 - Securities - Debt Securities by Maturity (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Due in one year or less, weighted average yield	1.92%
Due in one year or less, amortized cost	$ 11,406,000
Due in one year or less, fair value	$ 11,458,000
Due from one to five years, weighted average yield	0.96%
Due from one to five years, amortized cost	$ 185,889,000
Due from one to five years, fair value	$ 184,788,000
Due from five to ten years, weighted average yield	1.56%
Due from five to ten years, amortized cost	$ 288,599,000
Due from five to ten years, fair value	$ 285,609,000
Due after ten years, weighted average yield	1.99%
Due after ten years, amortized cost	$ 69,163,000
Due after ten years, fair value	$ 68,585,000
Weighted average yield	1.45%
Amortized cost	$ 597,463,000	$ 380,403,000
Fair value	$ 592,743,000	387,347,000
Collateralized Mortgage Backed Securities [Member]
No single maturity, weighted average yield	1.85%
No single maturity, amortized cost	$ 41,906,000
No single maturity, fair value	41,803,000
Amortized cost	41,906,000	23,869,000
Fair value	$ 41,803,000	24,890,000
Other Debt and Equity Securities [Member]
No single maturity, weighted average yield	3.75%
No single maturity, amortized cost	$ 500,000
No single maturity, fair value	500,000
Amortized cost	500,000	500,000
Fair value	$ 500,000	$ 500,000