Earnings Per Share (Schedule Of Earnings (Loss) Per Share, Basic And Diluted) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021	Apr. 30, 2020
Earnings Per Share [Abstract]
Net income (loss)	$ (29,722)	$ 61,193	$ 73,653
Denominator for basic earnings per common share - weighted-average shares	16,592	16,970	16,908
Stock options and restricted stock units	0	67	44
Denominator for diluted earnings (loss) per common share - weighted-average shares and assumed conversions	16,592	17,037	16,952
Net earnings (loss) per share, Basic (usd per share)	$ (1.79)	$ 3.61	$ 4.36
Net earnings (loss) per share, Diluted (usd per share)	$ (1.79)	$ 3.59	$ 4.34