Note 2 - Securities - Debt Securities by Maturity (Details) - USD ($)	Jun. 30, 2023	Dec. 31, 2022
Due in 2023, Weighted Average Yield	0.32%
Due in 2023, Amortized Cost	$ 12,635,000
Due in 2023, Fair Value	$ 12,401,000
Due in 2024 through 2028, Weighted Average Yield	1.32%
Due in 2024 through 2028, Amortized Cost	$ 319,466,000
Due in 2024 through 2028, Fair Value	$ 291,127,000
Due in 2029 through 2033, Weighted Average Yield	2.02%
Due in 2029 through 2033, Amortized Cost	$ 278,432,000
Due in 2029 through 2033, Fair Value	$ 237,792,000
Due in 2034 and beyond, Weighted Average Yield	3.64%
Due in 2034 and beyond, Amortized Cost	$ 39,434,000
Due in 2034 and beyond, Fair Value	$ 36,632,000
Total available for sale securities, weighted average yield	1.77%
Total available for sale securities, Amortized Cost	$ 686,841,000	$ 685,646,000
Securities available for sale	$ 608,972,000	602,936,000
Collateralized Mortgage-Backed Securities [Member]
No single maturity, weighted average yield	2.15%
No single maturity, amortized cost	$ 36,374,000
No single maturity, fair value	30,520,000
Total available for sale securities, Amortized Cost	36,374,000	38,002,000
Securities available for sale	$ 30,520,000	31,953,000
Other Debt and Equity Securities [Member]
No single maturity, weighted average yield	8.50%
No single maturity, amortized cost	$ 500,000
No single maturity, fair value	500,000
Total available for sale securities, Amortized Cost	500,000	500,000
Securities available for sale	$ 500,000	$ 500,000