Note 5 - Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	$ 4,820	$ 4,932	$ 11,143	$ 4,746
Tax effect	(951)	(998)	(2,224)	(592)
Net income	3,869	3,934	8,919	4,154
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	2	1	5	1
Income before income taxes	2	1	5	1
Tax effect			(1)
Net income	$ 2	$ 1	$ 4	$ 1