Note 6 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Effective Income Tax Rate Reconciliation, Percent, Total	26.00%	23.70%	22.80%	24.30%
Accrued Income Taxes, Total	$ 44		$ 44
Income Tax Expense (Benefit), Total	$ 1,247	$ 612	$ 646	$ 638