Note 2 - Securities - Debt Securities by Maturity (Details) - USD ($)	Jun. 30, 2022	Dec. 31, 2021
Due in 2022, Weighted Average Yield	1.35%
Due in 2022, Amortized Cost	$ 3,750,000
Due in 2022, Fair Value	$ 3,738,000
Due in 2023 through 2027, Weighted Average Yield	1.14%
Due in 2023 through 2027, Amortized Cost	$ 266,931,000
Due in 2023 through 2027, Fair Value	$ 250,890,000
Due in 2028 through 2032, Weighted Average Yield	1.84%
Due in 2028 through 2032, Amortized Cost	$ 311,780,000
Due in 2028 through 2032, Fair Value	$ 277,595,000
Due in 2033 and beyond, Weighted Average Yield	2.33%
Due in 2033 and beyond, Amortized Cost	$ 40,340,000
Due in 2033 and beyond, Fair Value	$ 34,551,000
Total available for sale securities, weighted average yield	1.60%
Total available for sale securities, Amortized Cost	$ 663,977,000	$ 597,463,000
Securities available for sale	$ 603,638,000	592,743,000
Collateralized Mortgage-Backed Securities [Member]
No single maturity, weighted average yield	2.04%
No single maturity, amortized cost	$ 40,676,000
No single maturity, fair value	36,364,000
Total available for sale securities, Amortized Cost	40,676,000	41,906,000
Securities available for sale	$ 36,364,000	41,803,000
Other Debt and Equity Securities [Member]
No single maturity, weighted average yield	3.88%
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