Earnings Per Share (Schedule Of Earnings (Loss) Per Share, Basic And Diluted) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2013
Earnings Per Share [Abstract]
Net income	$ 11,308	$ 7,282	$ 7,671	$ 9,238	$ 5,634	$ 2,901	$ 5,271	$ 6,655	$ 35,499	$ 20,461	$ 9,758
Denominator for basic earnings per common share - weighted-average shares									15,764	15,299	14,563
Stock options and restricted stock units									273	354	270
Denominator for diluted earnings (loss) per common share - weighted-average shares and assumed conversions									16,037	15,653	14,833
Net earnings per share, Basic (usd per share)	$ 0.71	$ 0.46	$ 0.49	$ 0.59	$ 0.36	$ 0.19	$ 0.35	$ 0.45	$ 2.25	$ 1.34	$ 0.67
Net earnings per share, Diluted (usd per share)	$ 0.69	$ 0.45	$ 0.48	$ 0.59	$ 0.36	$ 0.18	$ 0.34	$ 0.43	$ 2.21	$ 1.31	$ 0.66