CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Apr. 30, 2010	$ 30,433	$ 6,550	$ 855	$ (472)	$ 28,398	$ (4,898)
Net earnings	1,850				1,850
Other comprehensive income (loss)	(32)					(32)
Cash dividends declared, $.40, $.40, $.40 per share in the year ended April 30, 2011, 2012 and 2013, respectively	(1,030)				(1,030)
Stock options exercised, 13,850, 14,500, 26,750 shares in the year ended April 30, 2011, 2012 and 2013, respectively	151		11	140
Stock options granted, 136,400, 55,000, 40,000 shares in the year ended April 30, 2011, 2012 and 2013, respectively	225		225
Purchase of treasury stock, 8,323, 13,306, 13,752 shares in the year ended April 30, 2011, 2012 and 2013, respectively	(106)			(106)
Ending Balance at Apr. 30, 2011	31,491	6,550	1,091	(438)	29,218	(4,930)
Net earnings	1,031				1,031
Other comprehensive income (loss)	(2,246)					(2,246)
Cash dividends declared, $.40, $.40, $.40 per share in the year ended April 30, 2011, 2012 and 2013, respectively	(1,031)				(1,031)
Stock options exercised, 13,850, 14,500, 26,750 shares in the year ended April 30, 2011, 2012 and 2013, respectively	141		(11)	152
Stock options granted, 136,400, 55,000, 40,000 shares in the year ended April 30, 2011, 2012 and 2013, respectively	261		261
Purchase of treasury stock, 8,323, 13,306, 13,752 shares in the year ended April 30, 2011, 2012 and 2013, respectively	(136)			(136)
Ending Balance at Apr. 30, 2012	29,511	6,550	1,341	(422)	29,218	(7,176)
Net earnings	3,044				3,044
Other comprehensive income (loss)	(151)					(151)
Cash dividends declared, $.40, $.40, $.40 per share in the year ended April 30, 2011, 2012 and 2013, respectively	(1,071)				(1,071)
Stock options exercised, 13,850, 14,500, 26,750 shares in the year ended April 30, 2011, 2012 and 2013, respectively	285		(1)	286
Stock options granted, 136,400, 55,000, 40,000 shares in the year ended April 30, 2011, 2012 and 2013, respectively	227		227
Purchase of treasury stock, 8,323, 13,306, 13,752 shares in the year ended April 30, 2011, 2012 and 2013, respectively	(169)			(169)
Ending Balance at Apr. 30, 2013	$ 31,676	$ 6,550	$ 1,567	$ (305)	$ 31,191	$ (7,327)