Net Earnings Per Share (Schedule Of Earnings Per Share, Basic And Diluted) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Net Earnings Per Share [Abstract]
Net income	$ 5,271	$ 1,950	$ 11,926	$ 2,511
Denominator for basic net earnings per common share - weighted-average shares	15,230,584	14,498,269	15,089,995	14,456,938
Stock options and restricted stock units	351,000	180,000	389,000	170,000
Denominator for diluted net earnings per common share - weighted-average shares and assumed conversions	15,581,605	14,677,640	15,479,180	14,626,899
Basic	$ 0.35	$ 0.13	$ 0.79	$ 0.17
Diluted	$ 0.34	$ 0.13	$ 0.77	$ 0.17