Note 13 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Income Tax Expense (Benefit), Total	$ 2,908		$ 1,193	$ 3,529	$ 1,668
Effective Income Tax Rate Reconciliation, Percent, Total	10.70%		7.40%	7.10%	5.40%
GILTI Tax	$ 15,500			$ 27,900
Payment for the Transition Tax		$ 1,900
Unrecognized Tax Benefits, Ending Balance	17,200			17,200		$ 16,300
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	10,500			10,500		9,100
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	700			700		$ 500
Accrued Liabilities, Current [Member]
Transition Tax Liability	1,900			1,900
Income Tax Liabilities, Noncurrent [Member]
Transition Tax Liability	$ 20,100			$ 20,100