Note 13 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax Expense (Benefit), Total	$ 4,639		$ 1,445	$ 8,168	$ 3,112
Effective Income Tax Rate Reconciliation, Percent, Total	12.80%		5.80%	9.50%	5.50%
GILTI Tax	$ 18,400			$ 46,200
Payment for the Transition Tax		$ 1,900
Unrecognized Tax Benefits, Ending Balance	18,100			18,100		$ 16,300
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	11,200			11,200		9,100
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	800			800		$ 500
Accrued Liabilities, Current [Member]
Transition Tax Liability	1,900			1,900
Income Tax Liabilities, Noncurrent [Member]
Transition Tax Liability	$ 20,100			$ 20,100