Condensed Consolidated Statements of Earnings (Unaudited) (USD $)	3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Condensed Consolidated Statements of Earnings [Abstract]
Net sales	$ 39,434,770	$ 38,935,456
Costs and expenses
Costs of goods sold	34,787,012	34,778,631
General, selling and administrative costs	1,559,836	1,419,819
Total costs and expenses	36,346,848	36,198,450
Interest and other income	(12,208)	(17,872)
Earnings before income taxes	3,100,130	2,754,878
Income tax provision (benefit):
Current	1,035,928	946,142
Deferred	(27,652)	(22,675)
Total Income tax provision (benefit)	1,008,276	923,467
Net earnings	$ 2,091,854	$ 1,831,411
Average number of common shares outstanding:
Basic	6,799,444	6,799,444
Diluted	6,799,444	6,799,444
Net earnings per share:
Basic	$ 0.31	$ 0.27
Diluted	$ 0.31	$ 0.27
Cash dividends declared per common share	$ 0.13	$ 0.13