Note 11 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Income Tax Expense (Benefit), Total	$ 4,532	$ 4,478	$ 8,682	$ 8,333
Effective Income Tax Rate Reconciliation, Percent, Total	21.90%	19.60%	21.50%	18.60%
Effective Income Tax Rate, Increase (Decrease), Percentage	2.30%		2.90%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			21.00%
Unrecognized Tax Benefits, Ending Balance	$ 4,400		$ 4,400		$ 4,100