Net Earnings Per Share (Schedule of Earnings Per Share, Basic and Diluted) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Oct. 31, 2024	Jul. 31, 2024	Oct. 31, 2023	Jul. 31, 2023	Oct. 31, 2024	Oct. 31, 2023
Earnings Per Share [Abstract]
Net income	$ 27,686	$ 29,633	$ 30,341	$ 37,850	$ 57,319	$ 68,191
Denominator for basic net earnings per common share - weighted-average shares	15,327,191		16,322,069		15,438,854	16,406,239
Effect of dilutive securities:
Stock options and restricted stock units	108,000		99,000		118,000	99,000
Diluted (in shares)	15,435,311		16,420,760		15,557,210	16,505,266
Earnings Per Share, Basic [Abstract]
Basic (in usd per share)	$ 1.81		$ 1.86		$ 3.71	$ 4.16
Earnings Per Share, Diluted [Abstract]
Diluted (in usd per share)	$ 1.79		$ 1.85		$ 3.68	$ 4.13
Stock excluded from the calculation of net earnings per share (shares)	0		30,780		0	43,590
Document Period End Date					Oct. 31, 2024