Note 8 - Income Tax - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Federal income tax at statutory rate	21.00%	35.00%	35.00%
Federal income tax provision at statutory rate	$ 2,565	$ 1,491	$ 3,081
State income tax provision, net of federal income tax effects	641	177	397
Federal tax rate change		(9,336)
Adjustments for prior years	(293)
Other	(168)	(188)	180
Total income tax expense (benefit)	$ 2,745	$ (7,856)	$ 3,658
Effective income tax rate	22.50%	(184.50%)	41.50%