Note 9 - Income Taxes - Reconciliation of Expected Income Tax Expense With Reported Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Computed "expected" income tax expense	$ 4,342	$ 3,929	$ 7,135
Tax impact of enacted change in tax rate			1,560
Tax-exempt interest income	(1,019)	(1,255)	(2,144)
Nondeductible interest expense	96	69	89
Other, net	(208)	(183)	(347)
Total income tax expense	$ 3,211	$ 2,560	$ 6,293