Inventories (Schedule of Inventory) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Inventories [Abstract]
Finished goods	$ 68,971	$ 78,715
Work-in-process	18,071	17,693
Raw materials	20,885	19,764
Total inventories at current costs	107,927	116,172
Less: LIFO reserve	(9,318)	(9,064)
Inventory	$ 98,609	$ 107,108