Note 11 - Fair Values - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($)	Jun. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-Sale, Total	$ 603,638,000	$ 592,743,000
Fair Value, Inputs, Level 1 [Member]
Debt Securities, Available-for-Sale, Total	0	0
US Government Agencies Debt Securities [Member]
Debt Securities, Available-for-Sale, Total	407,335,000	390,371,000
Collateralized Mortgage-Backed Securities [Member]
Debt Securities, Available-for-Sale, Total	36,364,000	41,803,000
Municipal General Obligation Bonds [Member]
Debt Securities, Available-for-Sale, Total	137,673,000	137,594,000
Municipal Revenue Bonds [Member]
Debt Securities, Available-for-Sale, Total	21,766,000	22,475,000
Other Debt and Equity Securities [Member]
Debt Securities, Available-for-Sale, Total	500,000	500,000
Fair Value, Recurring [Member]
Total	620,707,000	597,352,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Total	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Total	620,084,000	596,675,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Total	623,000	677,000
Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member]
Debt Securities, Available-for-Sale, Total	407,335,000	390,371,000
Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Debt Securities, Available-for-Sale, Total	0	0
Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Debt Securities, Available-for-Sale, Total	407,335,000	390,371,000
Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Debt Securities, Available-for-Sale, Total	0	0
Fair Value, Recurring [Member] | Collateralized Mortgage-Backed Securities [Member]
Debt Securities, Available-for-Sale, Total	36,364,000	41,803,000
Fair Value, Recurring [Member] | Collateralized Mortgage-Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Debt Securities, Available-for-Sale, Total	0	0
Fair Value, Recurring [Member] | Collateralized Mortgage-Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Debt Securities, Available-for-Sale, Total	36,364,000	41,803,000
Fair Value, Recurring [Member] | Collateralized Mortgage-Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Debt Securities, Available-for-Sale, Total	0	0
Fair Value, Recurring [Member] | Municipal General Obligation Bonds [Member]
Debt Securities, Available-for-Sale, Total	137,673,000	137,594,000
Fair Value, Recurring [Member] | Municipal General Obligation Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Debt Securities, Available-for-Sale, Total	0	0
Fair Value, Recurring [Member] | Municipal General Obligation Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Debt Securities, Available-for-Sale, Total	137,050,000	136,917,000
Fair Value, Recurring [Member] | Municipal General Obligation Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Debt Securities, Available-for-Sale, Total	623,000	677,000
Fair Value, Recurring [Member] | Municipal Revenue Bonds [Member]
Debt Securities, Available-for-Sale, Total	21,766,000	22,475,000
Fair Value, Recurring [Member] | Municipal Revenue Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Debt Securities, Available-for-Sale, Total	0	0
Fair Value, Recurring [Member] | Municipal Revenue Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Debt Securities, Available-for-Sale, Total	21,766,000	22,475,000
Fair Value, Recurring [Member] | Municipal Revenue Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Debt Securities, Available-for-Sale, Total	0	0
Fair Value, Recurring [Member] | Other Debt and Equity Securities [Member]
Debt Securities, Available-for-Sale, Total	500,000	500,000
Fair Value, Recurring [Member] | Other Debt and Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Debt Securities, Available-for-Sale, Total	0	0
Fair Value, Recurring [Member] | Other Debt and Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Debt Securities, Available-for-Sale, Total	500,000	500,000
Fair Value, Recurring [Member] | Other Debt and Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Debt Securities, Available-for-Sale, Total	0	0
Fair Value, Recurring [Member] | Interest Rate Swap [Member]
Interest rate swaps	17,069,000	4,609,000
Fair Value, Recurring [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Interest rate swaps	0	0
Fair Value, Recurring [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Interest rate swaps	17,069,000	4,609,000
Fair Value, Recurring [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Interest rate swaps	$ 0	$ 0