Inventories (Tables)

12 Months Ended

Dec. 31, 2018

Inventory Disclosure [Abstract]

Summary of Inventories

Inventories in the Consolidated Balance Sheets are summarized as follows:

	December 31,
(Thousands)	2019		2018
Raw materials and supplies	$	35,612	$	33,182
Work in process	177,780		195,879
Finished goods	25,506		30,643
Subtotal	238,898		259,704
Less: LIFO reserve balance	48,508		44,833
Inventories	$	190,390	$	214,871