Quarterly Financial Information (unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Quarterly Financial Information (unaudited) [Abstract]
Net sales	$ 128,530	$ 147,974	$ 145,376	$ 150,102	$ 100,719	$ 91,766	$ 100,415	$ 110,038	$ 571,982	$ 402,938	$ 400,575
Gross profit	41,874	53,726	52,957	58,088	33,033	23,616	25,845	25,366	206,645	107,860	101,619
Net income (loss)	$ 20,753	$ 20,409	$ 19,131	$ 23,595	$ 13,186	$ 4,537	$ 6,563	$ 4,990	$ 83,888	$ 29,276	$ 8,515
Basic income (loss) per share (in dollars per share)	$ 0.86	$ 0.83	$ 0.77	$ 0.95	$ 0.53	$ 0.18	$ 0.26	$ 0.20	$ 3.41	$ 1.16	$ 0.33
Diluted income (loss) per share (in dollars per share)	$ 0.85	$ 0.82	$ 0.76	$ 0.94	$ 0.53	$ 0.18	$ 0.26	$ 0.20	$ 3.39	$ 1.15	$ 0.33