Net Earnings Per Share (Schedule of Earnings Per Share, Basic and Diluted) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Jan. 31, 2024	Oct. 31, 2023	Jul. 31, 2023	Jan. 31, 2023	Oct. 31, 2022	Jul. 31, 2022	Jan. 31, 2024	Jan. 31, 2023
Earnings Per Share [Abstract]
Net income	$ 21,227	$ 30,341	$ 37,850	$ 14,728	$ 28,784	$ 20,070	$ 89,418	$ 63,582
Denominator for basic net earnings per common share - weighted-average shares	15,991,520			16,621,827			16,267,999	16,606,700
Effect of dilutive securities:
Stock options and restricted stock units	132,000			74,000			113,000	54,000
Diluted (in shares)	16,124,198			16,695,714			16,380,756	16,661,234
Earnings Per Share, Basic [Abstract]
Basic (in usd per share)	$ 1.33			$ 0.89			$ 5.50	$ 3.83
Earnings Per Share, Diluted [Abstract]
Diluted (in usd per share)	$ 1.32			$ 0.88			$ 5.46	$ 3.82
Stock excluded from the calculation of net earnings per share (shares)	0			0			40,170	0
Document Period End Date							Jan. 31, 2024