Note 11 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Income Tax Expense (Benefit), Total	$ 4,150	$ 3,855
Effective Income Tax Rate Reconciliation, Percent, Total	21.10%	17.60%
Effective Income Tax Rate, Increase (Decrease), Percentage	3.50%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Unrecognized Tax Benefits, Ending Balance	$ 4,300		$ 4,100