Consolidated Statements Of Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Oct. 02, 2011	Sep. 30, 2012	Oct. 02, 2011
Consolidated Statements Of Earnings [Abstract]
Net sales	$ 116,813	$ 104,861	$ 330,700	$ 312,015
Cost of sales	93,906	81,204	267,847	245,739
Gross profit	22,907	23,657	62,853	66,276
Selling and general expenses	7,874	4,403	19,627	13,512
Operating profit	15,033	19,254	43,226	52,764
Other income	47	264	168	1,289
Earnings before provision for income taxes	15,080	19,518	43,394	54,053
Income tax provision	5,679	7,132	15,946	19,487
Net earnings	9,401	12,386	27,448	34,566
Weighted average shares outstanding:
Basic	6,891	6,875	6,888	6,873
Diluted	6,893	6,876	6,890	6,874
Net earnings per share:
Basic	$ 1.36	$ 1.80	$ 3.98	$ 5.03
Diluted	$ 1.36	$ 1.80	$ 3.98	$ 5.03
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on available-for-sale securities	(1)	(18)	(15)	(19)
Comprehensive income	$ 9,400	$ 12,368	$ 27,433	$ 34,547
Cash dividends declared and paid per common share	$ 0.00	$ 0.00	$ 6.00	$ 8.25