Note 7 - Property, Plant and Equipment (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Abstract]
Depreciation	$ 32,195	$ 29,970	$ 23,654
Payments To Acquire Property, Plant, and Equipment and Capital Expenditures Incurred But Not Yet Paid	$ 70,547	$ 53,900