Note 8 - Income Tax - Tax Effects of Temporary Differences (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Federal income taxes
Current	$ 1,036	$ 1,201	$ 1,176
Deferred	898	(9,332)	1,872
Total federal tax expense (benefit)	1,934	(8,131)	3,048
State income taxes
Current	503	284	308
Deferred	308	(9)	302
Total state tax expense	811	275	610
Total income tax expense (benefit)	$ 2,745	$ (7,856)	$ 3,658