Schedule III Supplemental Financial Information (Detail) - Quarterly Results of Operations, 2012 (USD $) Share data 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
Net sales	$ 291,724,000		$ 342,560,000		$ 367,365,000		$ 382,052,000		$ 319,944,000		$ 348,547,000		$ 299,000,000		$ 294,381,000		$ 1,383,701,000		$ 1,261,872,000
Operating income (a)	(8,182,000)	[1]	4,624,000	[1]	9,744,000	[1]	12,263,000	[1]	3,941,000		9,315,000		13,899,000		17,313,000		18,449,000	[1]	44,468,000		6,102,000
Income (loss) before income taxes	(10,171,000)		2,555,000		7,566,000		10,189,000		917,000		6,987,000		13,073,000		16,508,000		10,139,000		37,485,000		3,797,000
Net income (loss)	(10,118,000)		1,639,000		4,526,000		6,230,000		565,000		6,136,000		7,946,000		10,323,000		2,277,000		24,970,000
Basic net income (loss) per share (in Dollars per share)	$ (0.92)		$ 0.15		$ 0.41		$ 0.57		$ 0.05		$ 0.56		$ 0.73		$ 0.94		$ 0.21		$ 2.28		$ 0.20
Weighted average shares outstanding - basic (in Shares)	10,993		10,961		10,960		10,988		10,941		10,937		10,905		10,935		10,989		10,937		10,905
Diluted net income (loss) per share (in Dollars per share)	$ (0.92)		$ 0.15		$ 0.41		$ 0.57		$ 0.05		$ 0.56		$ 0.73		$ 0.94		$ 0.21		$ 2.28		$ 0.20
Weighted average shares outstanding - diluted (in Shares)	10,993		10,967		10,989		10,997		10,953		10,951		10,947		10,945		10,995		10,951		10,918
Maximum [Member]
Market price of common stock	22.14	[2]	18.41	[2]	24.88	[2]	27.48	[2]	25.94	[2]	29.21	[2]	35.00	[2]	33.21	[2]	27.48	[2]	35.00	[2]
Minimum [Member]
Market price of common stock	$ 16.85	[2]	$ 15.07	[2]	$ 15.06	[2]	$ 21.78	[2]	$ 14.58	[2]	$ 15.82	[2]	$ 24.76	[2]	$ 25.87	[2]	$ 15.06	[2]	$ 14.58	[2]

[1] Operating income includes $6,583 of goodwill impairment charges related to the Company's flat products Southern region in the 4th quarter of 2012.

[2] Represents the high and low sales prices of our common stock as reported by the Nasdaq Global Select Market.