Supplementary Quarterly Financial Information (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplementary Quarterly Financial Information (Unaudited)
Net sales	$ 359,233	$ 336,801	$ 334,991	$ 325,337	$ 357,191	$ 335,811	$ 350,002	$ 316,995	$ 1,356,362	$ 1,359,999	$ 1,342,298
Gross profit	50,187	45,199	47,976	48,705	48,143	47,910	49,113	44,333	192,067	189,499	184,130
Income (loss) from continuing operations	2,054	139	1,808	3,034	1,943	2,129	3,301	1,272	7,035	8,645	5,693
Loss from discontinued operations, net of taxes	(481)	(279)	(663)	(147)	(137)	(205)	(138)	(36)	(1,570)	(516)	(599)
Net income (loss)	$ 1,573	$ (140)	$ 1,145	$ 2,887	$ 1,806	$ 1,924	$ 3,163	$ 1,236	$ 5,465	$ 8,129	$ 5,094
Basic and Diluted Earnings Per Common Share
Basic (in dollars per share)	$ 0.17	$ 0.01	$ 0.14	$ 0.25	$ 0.16	$ 0.18	$ 0.29	$ 0.11	$ 0.45	$ 0.70	$ 0.42
Diluted (in dollars per share)	$ 0.16	$ 0.01	$ 0.14	$ 0.24	$ 0.16	$ 0.18	$ 0.28	$ 0.11	$ 0.42	$ 0.68	$ 0.42