Quarterly Operating Results (Unaudited) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Oct. 02, 2011	Jul. 03, 2011	Apr. 03, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net Sales	$ 67,084	$ 56,555	$ 45,836	$ 43,853	$ 64,886	$ 58,877	$ 36,550	$ 48,497	$ 213,328	$ 208,810	$ 175,805
Gross profit	18,046	16,442	8,834	7,829	22,480	18,830	10,983	13,039	51,151	65,332	44,527
Net (loss) income	3,376	2,894	(6,237)	(7,088)	5,326	3,373	(1,919)	(1,792)	(7,055)	4,988	(11,149)
Operating income									18,557	32,503	18,478
Adjustments
Gross profit										(208)	105
Net (loss) income										(208)	105
Operating income										(208)	105
Post-retirement health plan accounting | Adjustments
Gross profit		115	25	25	111	32	32	33
Net (loss) income		115	25	25	111	32	32	33
Sales cut-off | Adjustments
Net Sales			724	(724)
Gross profit			453	(453)
Net (loss) income			$ 453	$ (453)