Guarantor Financial Information (Condensed Consolidated Statements of Operations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013	Jun. 30, 2012
Net sales	$ 423,593	$ 436,674	$ 869,015	$ 823,782
Costs and expenses:
Cost of sales and operating expenses	309,922	314,138	632,608	590,607
Selling, general and administrative expenses	40,793	36,894	83,086	74,263
Depreciation and amortization	22,076	21,674	43,943	42,434
Total costs and expenses	372,791	372,706	759,637	707,304
Operating income	50,802	63,968	109,378	116,478
Interest expense	(5,669)	(5,753)	(11,294)	(12,678)
Other income/(expense), net	(418)	270	649	(338)
Equity in net loss of unconsolidated subsidiary	(1,962)	(656)	(3,157)	(892)
Earnings in investments in subsidiaries	0	0	0	0
Income before income taxes	42,753	57,829	95,576	102,570
Income taxes	16,335	21,604	36,753	37,774
Net income	26,418	36,225	58,823	64,796
Issuer [Member]
Net sales	159,392	184,570	321,264	337,558
Costs and expenses:
Cost of sales and operating expenses	124,146	142,905	248,250	264,002
Selling, general and administrative expenses	22,106	18,927	44,673	39,712
Depreciation and amortization	5,817	5,816	11,955	12,112
Total costs and expenses	152,069	167,648	304,878	315,826
Operating income	7,323	16,922	16,386	21,732
Interest expense	(5,666)	(5,752)	(11,287)	(12,677)
Other income/(expense), net	(612)	(588)	326	(1,230)
Equity in net loss of unconsolidated subsidiary	0	0	0	0
Earnings in investments in subsidiaries	25,767	29,519	55,485	59,851
Income before income taxes	26,812	40,101	60,910	67,676
Income taxes	394	3,876	2,087	2,880
Net income	26,418	36,225	58,823	64,796
Guarantors [Member]
Net sales	309,689	300,190	629,100	573,699
Costs and expenses:
Cost of sales and operating expenses	231,381	219,470	465,902	414,283
Selling, general and administrative expenses	18,674	17,933	38,360	34,478
Depreciation and amortization	16,253	15,853	31,976	30,311
Total costs and expenses	266,308	253,256	536,238	479,072
Operating income	43,381	46,934	92,862	94,627
Interest expense	(3)	(1)	(7)	(1)
Other income/(expense), net	212	878	347	905
Equity in net loss of unconsolidated subsidiary	0	0	0	0
Earnings in investments in subsidiaries	0	0	0	0
Income before income taxes	43,590	47,811	93,202	95,531
Income taxes	16,663	17,938	35,840	35,184
Net income	26,927	29,873	57,362	60,347
Non-guarantors [Member]
Net sales	1,761	3,721	5,895	6,275
Costs and expenses:
Cost of sales and operating expenses	1,644	3,570	5,700	6,072
Selling, general and administrative expenses	13	34	53	73
Depreciation and amortization	6	5	12	11
Total costs and expenses	1,663	3,609	5,765	6,156
Operating income	98	112	130	119
Interest expense	0	0	0	0
Other income/(expense), net	(18)	(20)	(24)	(13)
Equity in net loss of unconsolidated subsidiary	(1,962)	(656)	(3,157)	(892)
Earnings in investments in subsidiaries	0	0	0	0
Income before income taxes	(1,882)	(564)	(3,051)	(786)
Income taxes	(722)	(210)	(1,174)	(290)
Net income	(1,160)	(354)	(1,877)	(496)
Eliminations [Member]
Net sales	(47,249)	(51,807)	(87,244)	(93,750)
Costs and expenses:
Cost of sales and operating expenses	(47,249)	(51,807)	(87,244)	(93,750)
Selling, general and administrative expenses	0	0	0	0
Depreciation and amortization	0	0	0	0
Total costs and expenses	(47,249)	(51,807)	(87,244)	(93,750)
Operating income	0	0	0	0
Interest expense	0	0	0	0
Other income/(expense), net	0	0	0	0
Equity in net loss of unconsolidated subsidiary	0	0	0	0
Earnings in investments in subsidiaries	(25,767)	(29,519)	(55,485)	(59,851)
Income before income taxes	(25,767)	(29,519)	(55,485)	(59,851)
Income taxes	0	0	0	0
Net income	$ (25,767)	$ (29,519)	$ (55,485)	$ (59,851)