Inventories (Tables)

3 Months Ended

Mar. 31, 2018

Inventory Disclosure [Abstract]

Schedule of Inventory, Current [Table Text Block]

Inventories consisted of the following (in thousands): 

	March 31, 2018		December 31, 2017
Raw material	$	78,732	$	82,397
Work in process	51,545		42,304
Finished goods	165,271		163,956
Total inventories	$	295,548	$	288,657