Note 7 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Expense (Benefit), Total	$ 709	$ 1,160	$ 2,180	$ 3,310
Effective Income Tax Rate Reconciliation, Percent, Total	15.30%	15.90%	19.40%	21.10%