Note 5 - Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	$ 4,692	$ 3,821	$ 9,438	$ 11,839
Tax effect	(914)	(731)	(1,506)	(2,227)
Net income	3,778	3,090	7,932	9,612
Reclassification out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Unrealized net holding gains (losses) on available-for-sale securities	15	3	16	(36)
Income before income taxes	15	3	16	(36)
Tax effect	(3)		(3)	8
Net income	$ 12	$ 3	$ 13	$ (28)