Note 6 - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Property, Plant and Equipment, Gross	$ 369,047	$ 320,442
Land [Member]
Property, Plant and Equipment, Gross	1,316	1,316
Building and Building Improvements [Member]
Property, Plant and Equipment, Gross	38,241	37,356
Machinery and Equipment [Member]
Property, Plant and Equipment, Gross	190,949	186,863
Vehicles [Member]
Property, Plant and Equipment, Gross	1,830	1,830
Nondepreciable Machinery and Equipment [Member]
Property, Plant and Equipment, Gross	12,397	11,976
Construction in Progress [Member]
Property, Plant and Equipment, Gross	$ 124,314	$ 81,101