Inventories (Tables)

3 Months Ended

Mar. 31, 2022

Inventory Disclosure [Abstract]

Schedule of Inventory, Current [Table Text Block]

Components of inventories as of March 31, 2022 and December 31, 2021 are as follows: 

	March 31, 2022		December 31, 2021
	(in thousands)
Finished goods	$	54,564	$	59,925
Raw materials	3,450		2,827
Parts and supplies	5,010		4,713
Work in progress	1,625		1,633
Total inventories	$	64,649	$	69,098