Consolidated Statements of Earnings (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2012	Nov. 30, 2011
Consolidated Statements of Earnings [Abstract]
Net sales	$ 128,996	$ 121,846	$ 409,868	$ 395,488
Cost of goods sold	98,385	91,663	317,059	291,510
Gross profit margin	30,611	30,183	92,809	103,978
Selling, general and administrative	20,591	19,094	63,948	58,398
Gain from disposal of assets	3	(8)	(6)	(133)
Income from operations	10,017	11,097	28,867	45,713
Other income (expense)
Interest expense	(335)	(405)	(1,206)	(1,887)
Other, net	(182)	318	(97)	313
Total other income (expense)	(517)	(87)	(1,303)	(1,574)
Earnings before income taxes	9,500	11,010	27,564	44,139
Provision for income taxes	3,330	4,118	9,923	16,111
Net earnings	$ 6,170	$ 6,892	$ 17,641	$ 28,028
Weighted average common shares outstanding
Basic	26,025,072	25,934,972	26,011,692	25,930,484
Diluted	26,045,883	25,954,399	26,031,738	25,955,104
Per share amounts
Net earnings - basic	$ 0.24	$ 0.27	$ 0.68	$ 1.08
Net earnings - diluted	$ 0.24	$ 0.27	$ 0.68	$ 1.08
Cash dividends per share	$ 0.175	$ 0.155	$ 0.525	$ 0.465