Consolidated Income Statements (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 31, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Jun. 28, 2014	Jun. 29, 2013	Sep. 27, 2014	Sep. 28, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Net Revenues	$ 187,612	$ 188,164	$ 186,516	$ 179,753	$ 187,975	$ 181,288	$ 191,472	$ 175,915	$ 366,269	$ 367,387	$ 554,433	$ 548,675	$ 742,045	$ 736,650	$ 747,037
Cost of Sales
Cost of Sales		155,052	148,838	143,838		147,549	153,898	142,641	292,676	296,539	447,728	444,088	601,713	612,498	603,060
Gross Profit	33,627	33,112	37,678	35,915	19,565	33,739	37,574	33,274	73,593	70,848	106,705	104,587	140,332	124,152	143,977
Selling, General and Administrative Expenses		23,050	20,868	21,087		20,351	22,273	22,551	41,955	44,824	65,005	65,175	88,565	84,849	87,055
Operating Income		10,062	16,810	14,828		13,388	15,301	10,723	31,638	26,024	41,700	39,412	51,767	39,303	56,922
Interest Expense		(6,975)	(6,994)	(7,125)		(7,403)	(7,442)	(7,823)	(14,119)	(15,265)	(21,094)	(22,668)	(28,077)	(29,918)	(32,798)
Other Income		1,600				0					1,600	0	2,550	0	0
Income Before Taxes	4,034	4,687	9,816	7,703	(7,359)	5,985	7,859	2,900	17,519	10,759	22,206	16,744	26,240	9,385	24,124
Income Tax Expense (Benefit)	(1,122)	1,754	3,197	2,544	(2,115)	(1,000)	2,193	(1,071)	5,741	1,122	7,495	122	6,373	(1,993)	6,501
Net Income	$ 5,156	$ 2,933	$ 6,619	$ 5,159	$ (5,244)	$ 6,985	$ 5,666	$ 3,971	$ 11,778	$ 9,637	$ 14,711	$ 16,622	$ 19,867	$ 11,378	$ 17,623
Earnings Per Share
Basic earnings per share (in dollars per share)	$ 0.47	$ 0.27	$ 0.61	$ 0.48	$ (0.49)	$ 0.65	$ 0.53	$ 0.37	$ 1.08	$ 0.91	$ 1.35	$ 1.56	$ 1.82	$ 1.06	$ 1.67
Diluted earnings per share (in dollars per share)	$ 0.46	$ 0.26	$ 0.60	$ 0.46	$ (0.49)	$ 0.64	$ 0.53	$ 0.37	$ 1.06	$ 0.90	$ 1.31	$ 1.54	$ 1.79	$ 1.05	$ 1.66
Weighted-Average Number of Shares Outstanding
Basic (in shares)		10,921	10,871	10,844		10,722	10,648	10,600	10,864	10,624	10,902	10,657	10,897	10,695	10,580
Diluted (in shares)		11,150	11,045	11,107		10,917	10,790	10,670	11,122	10,731	11,202	10,785	11,126	10,852	10,628