Note 5 - Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	$ 4,534	$ 6,323
Tax effect	(824)	(1,273)
Net income	3,710	5,050
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Unrealized net holding gains on available-for-sale securities	1	3
Income before income taxes	1	3
Tax effect		(1)
Net income	$ 1	$ 2