Note 2 - Securities - Debt Securities by Maturity (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Due in 2022, Weighted Average Yield	1.98%
Due in 2022, Amortized Cost	$ 10,171,000
Due in 2022, Fair Value	$ 10,171,000
Due in 2023 through 2027, Weighted Average Yield	1.11%
Due in 2023 through 2027, Amortized Cost	$ 263,429,000
Due in 2023 through 2027, Fair Value	$ 251,105,000
Due in 2028 through 2032, Weighted Average Yield	1.74%
Due in 2028 through 2032, Amortized Cost	$ 295,377,000
Due in 2028 through 2032, Fair Value	$ 273,366,000
Due in 2033 and beyond, Weighted Average Yield	2.13%
Due in 2033 and beyond, Amortized Cost	$ 36,339,000
Due in 2033 and beyond, Fair Value	$ 32,773,000
Total available for sale securities, weighted average yield	1.52%
Total available for sale securities, Amortized Cost	$ 646,031,000	$ 597,463,000
Securities available for sale	$ 605,661,000	592,743,000
Collateralized Mortgage-Backed Securities [Member]
No single maturity, weighted average yield	1.95%
No single maturity, amortized cost	$ 40,215,000
No single maturity, fair value	37,746,000
Total available for sale securities, Amortized Cost	40,215,000	41,906,000
Securities available for sale	$ 37,746,000	41,803,000
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
Total available for sale securities, Amortized Cost	500,000	500,000
Securities available for sale	$ 500,000	$ 500,000