Inventories (Tables)

6 Months Ended

Jun. 30, 2019

Inventory Disclosure [Abstract]

Schedule of Inventory, Current [Table Text Block]

Components of inventories as of June 30, 2019 and December 31, 2018 are as follows: 

	June 30, 2019		December 31, 2018
	(In Thousands)
Finished goods	$	63,579	$	69,762
Raw materials	3,428		3,503
Parts and supplies	44,120		47,386
Work in progress	27,297		22,920
Total inventories	$	138,424	$	143,571