Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Inventories [Abstract]
Raw materials and supplies	$ 119,711	$ 113,632
Work in process	26,589	24,290
Finished products	82,848	81,263
Inventory reserves	(37,722)	(37,233)
Total Inventory	$ 191,426	$ 181,952