Inventory (Schedule of Inventory) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Inventory [Abstract]
Finished goods	$ 78,715	$ 71,758
Work-in-process	17,693	8,004
Raw materials	19,764	19,885
Total inventories at current costs	116,172	99,647
Less: LIFO reserve	(9,064)	(10,183)
Inventory	107,108	89,464
Excess of Book LIFO Over Tax LIFO	11,686	14,636
Effect Of Inventory Liquidation On Cost Of Good Sold, Increase/(Decrease)	$ 15	$ (33)	$ 1,046