CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) (USD $)	12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Stock options exercised, shares	26,750	14,500	13,850
Stock options granted, shares	40,000	55,000	136,400
Additional Paid-in Capital [Member]
Stock options exercised, shares	26,750	14,500	13,850
Stock options granted, shares	40,000	55,000	136,400
Treasury Stock [Member]
Stock options exercised, shares	26,750	14,500	13,850
Treasury stock, shares	13,752	13,306	8,323
Retained Earnings [Member]
Cash dividends declared, per share	$ 0.40	$ 0.40	$ 0.40