Inventories (Schedule of Inventory) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Inventories [Abstract]
Finished goods	$ 61,853	$ 55,166
Work-in-process	7,520	11,332
Raw materials	17,302	19,485
Total inventories at current costs	86,675	85,983
Less: LIFO reserve	(9,031)	(9,027)
Inventory	$ 77,644	$ 76,956