Note 8 - Income Tax - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Federal income tax at statutory rate	21.00%	21.00%	35.00%
Federal income tax provision at statutory rate	$ 2,140	$ 2,565	$ 1,491
State income tax provision, net of federal income tax effects	548	641	177
Federal tax rate change			(9,336)
Adjustments for prior years	(222)	(302)	(121)
Other	(73)	(159)	(67)
Total income tax expense (benefit)	$ 2,393	$ 2,745	$ (7,856)
Effective income tax rate	23.50%	22.50%	(184.50%)