CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net sales	$ 547,657	$ 563,985	$ 450,745
Cost of goods sold	(502,779)	(520,015)	(417,918)
Gross margin	44,878	43,970	32,827
Other operating income (expense):
Selling expense	(8,093)	(7,351)	(6,758)
General and administrative expense	(15,820)	(15,238)	(14,096)
Defined benefit pension credit	6,858	24,388	4,654
Other postretirement benefit credit	6,075	5,799	5,258
Total other operating income (expense)	(10,980)	7,598	(10,942)
Operating income	33,898	51,568	21,885
Nonoperating income (expense):
Interest expense	(1,213)	(1,218)	(1,863)
Other, net	(518)	699	637
Total nonoperating expense	(1,731)	(519)	(1,226)
Income before income taxes	32,167	51,049	20,659
Income tax expense	(11,943)	(20,838)	(8,645)
Net income	$ 20,224	$ 30,211	$ 12,014
Basic and diluted income per share	$ 1.67	$ 2.50	$ 0.99
Basic and diluted weighted average shares outstanding	12,102	12,102	12,102