Note 5 - Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	$ 3,821	$ 3,978	$ 11,839	$ 10,904
Tax effect	(731)	(767)	(2,227)	(1,896)
Net income	3,090	$ 3,211	9,612	9,008
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	3		(36)	3
Income before income taxes	3		(36)	3
Tax effect			8	(1)
Net income	$ 3		$ (28)	$ 2