Guarantor and Non-guarantor Financial Statements, Condensed Consolidated Statements of Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS
Net sales	$ 183,659	$ 166,784
Cost of goods sold	162,728	149,761
Gross profit	20,931	17,023
Operating expenses	11,603	10,454
Income from operations	9,328	6,569
Other income (expense):
Interest expense, net	(8,350)	(8,420)
Equity in earnings of subsidiaries	0	0
Other income (expense), net	(1,172)	(530)
Income (loss) before income taxes from continuing operations	(194)	(2,381)
Income tax provision (benefit)	386	904
Income (loss) from continuing operations	(580)	(3,285)
Discontinued operations, net of tax	(8)	(288)
Net income (loss)	(588)	(3,573)
Comprehensive income (loss)	686	(3,240)
Eliminations [Member]
CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS
Net sales	(56,853)	(48,703)
Cost of goods sold	(56,552)	(48,264)
Gross profit	(301)	(439)
Operating expenses	0	0
Income from operations	(301)	(439)
Other income (expense):
Interest expense, net	0	0
Equity in earnings of subsidiaries	(7,613)	(5,673)
Other income (expense), net	0	0
Income (loss) before income taxes from continuing operations	(7,914)	(6,112)
Income tax provision (benefit)	0	0
Income (loss) from continuing operations	(7,914)	(6,112)
Discontinued operations, net of tax	0	0
Net income (loss)	(7,914)	(6,112)
Comprehensive income (loss)	(9,166)	(6,434)
Parent [Member]
CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS
Net sales	119,499	108,531
Cost of goods sold	107,236	98,882
Gross profit	12,263	9,649
Operating expenses	11,303	10,122
Income from operations	960	(473)
Other income (expense):
Interest expense, net	(8,688)	(8,657)
Equity in earnings of subsidiaries	7,613	5,673
Other income (expense), net	(569)	(77)
Income (loss) before income taxes from continuing operations	(684)	(3,534)
Income tax provision (benefit)	(96)	39
Income (loss) from continuing operations	(588)	(3,573)
Discontinued operations, net of tax	0	0
Net income (loss)	(588)	(3,573)
Comprehensive income (loss)	686	(3,240)
Guarantor Subsidiaries [Member]
CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS
Net sales	89,243	74,302
Cost of goods sold	82,017	69,704
Gross profit	7,226	4,598
Operating expenses	254	280
Income from operations	6,972	4,318
Other income (expense):
Interest expense, net	(54)	(61)
Equity in earnings of subsidiaries	0	0
Other income (expense), net	0	63
Income (loss) before income taxes from continuing operations	6,918	4,320
Income tax provision (benefit)	143	143
Income (loss) from continuing operations	6,775	4,177
Discontinued operations, net of tax	0	0
Net income (loss)	6,775	4,177
Comprehensive income (loss)	6,865	4,164
Non-guarantor Subsidiaries [Member]
CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS
Net sales	31,770	32,654
Cost of goods sold	30,027	29,439
Gross profit	1,743	3,215
Operating expenses	46	52
Income from operations	1,697	3,163
Other income (expense):
Interest expense, net	392	298
Equity in earnings of subsidiaries	0	0
Other income (expense), net	(603)	(516)
Income (loss) before income taxes from continuing operations	1,486	2,945
Income tax provision (benefit)	339	722
Income (loss) from continuing operations	1,147	2,223
Discontinued operations, net of tax	(8)	(288)
Net income (loss)	1,139	1,935
Comprehensive income (loss)	$ 2,301	$ 2,270