Consolidated statements of operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Statement [Abstract]
Net sales	$ 299,293	$ 282,349	$ 599,587	$ 564,076
Cost of goods sold	241,147	227,648	486,974	454,396
Gross profit	58,146	54,701	112,613	109,680
Selling, general, and administrative expenses	35,929	32,415	69,268	72,565
Restructuring and other charges	79	2,128	393	2,809
Operating income	22,138	20,158	42,952	34,306
Interest expense–net	5,390	3,731	11,026	10,068
Loss on extinguishment of debt and refinancing fees	0	0	0	4,256
Income before income taxes	16,748	16,427	31,926	19,982
Income tax expense	6,792	4,963	12,503	6,675
Net income	9,956	11,464	19,423	13,307
Less net income attributable to noncontrolling interest	0	96	0	659
Net income attributable to common stockholders	$ 9,956	$ 11,368	$ 19,423	$ 12,648
Basic earnings per share:
Earnings per share	$ 0.32	$ 0.36	$ 0.62	$ 0.41
Weighted average shares outstanding	31,514	31,239	31,447	31,173
Diluted earnings per share:
Earnings per share	$ 0.32	$ 0.36	$ 0.62	$ 0.4
Weighted average shares outstanding	31,593	31,364	31,571	31,314
Dividends declared per common share	$ 0.10	$ 0.10	$ 0.20	$ 0.20