Inventories (Tables)

3 Months Ended

Mar. 31, 2019

Inventory Disclosure [Abstract]

Schedule of Inventory, Current [Table Text Block]

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

	March 31, 2019		December 31, 2018
	(In Thousands)
Finished goods	$	72,831	$	69,762
Raw materials	3,279		3,503
Parts and supplies	44,915		47,386
Work in progress	35,603		22,920
Total inventories	$	156,628	$	143,571