Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Inventories
Raw materials and supplies	$ 47,240	$ 31,878
Work in process	15,645	21,455
Finished goods	29,351	19,867
Total inventory	92,236	73,200
Less reserve for excess and obsolete inventories	(1,586)	(2,535)
Total inventory, net	$ 90,650	$ 70,665