Quarterly Financial Data - Schedule of Quarterly Financial Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule Of Quarterly Financial Data [Line Items]
Net sales	$ 177,137	$ 182,374	$ 209,275	$ 190,245	$ 215,364	$ 176,780	$ 235,619	$ 177,493	$ 759,031	$ 805,256	$ 609,905
Gross profit	40,370	33,187	65,735	44,444	62,821	34,257	72,086	53,854	183,736	223,018	138,625
Income from continuing operations	11,622	6,710	26,130	14,324	28,002	6,324	28,698	20,960	58,786	83,984	29,715
Net loss from discontinued operations	62	2	97	21	14	18	53	57	182	142	141
Net income	11,560	6,708	26,033	14,303	27,988	6,306	28,645	20,903	58,604	83,842	29,574
Net income applicable to common stock	$ 11,560	$ 6,708	$ 26,033	$ 14,003	$ 27,988	$ 6,306	$ 28,645	$ 20,598	$ 58,304	$ 83,537	$ 29,269
Basic:
Income from continuing operations	$ 0.52	$ 0.30	$ 1.17	$ 0.63	$ 1.26	$ 0.28	$ 1.29	$ 0.97	$ 2.62	$ 3.81	$ 1.39
Net loss from discontinued operations									$ (0.01)	$ (0.01)	$ (0.01)
Net income	$ 0.52	$ 0.30	$ 1.17	$ 0.63	$ 1.26	$ 0.28	$ 1.29	$ 0.97	$ 2.61	$ 3.80	$ 1.38
Diluted:
Income from continuing operations	$ 0.49	$ 0.28	$ 1.11	$ 0.61	$ 1.19	$ 0.27	$ 1.22	$ 0.90	$ 2.50	$ 3.59	$ 1.33
Net loss from discontinued operations									$ (0.01)	$ (0.01)	$ (0.01)
Net income	$ 0.49	$ 0.28	$ 1.11	$ 0.61	$ 1.19	$ 0.27	$ 1.22	$ 0.90	$ 2.49	$ 3.58	$ 1.32