Inventory (Schedule of Inventory) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Inventory [Abstract]
Finished goods	$ 62,547	$ 65,335
Work-in-process	20,178	16,188
Raw materials	19,492	21,855
Total inventories at current costs	102,217	103,378
Less: LIFO reserve	(5,821)	(8,289)
Inventory	96,396	95,089
Excess of Book LIFO Over Tax LIFO	5,046	11,697
Effect Of Inventory Liquidation On Cost Of Good Sold, Increase/(Decrease)	$ 115	$ 6	$ 1,128