Consolidated Statements Of Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements Of Comprehensive Income [Abstract]
Net sales	$ 472,490	$ 431,021	$ 479,000
Cost of sales	377,627	337,262	365,426
Gross profit	94,863	93,759	113,574
Selling and general expenses	35,144	20,022	16,323
Operating profit	59,719	73,737	97,251
Other income, principally interest	705	1,288	2,104
Earnings before provision for income taxes	60,424	75,025	99,355
Provision for income taxes	21,549	27,057	35,824
Net earnings	38,875	47,968	63,531
Weighted average common shares outstanding:
Basic	6,889	6,875	6,864
Diluted	6,891	6,876	6,864
Net earnings per share:
Basic	$ 5.64	$ 6.98	$ 9.26
Diluted	$ 5.64	$ 6.98	$ 9.26
Other comprehensive income (loss), net of tax:
Unrealized loss on available-for-sale securities, net of tax	(19)	(57)	(514)
Comprehensive income	$ 38,856	$ 47,911	$ 63,017