Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020
Share-based Payment Arrangement [Abstract]
Option to purchase common stock (in shares)			1,308,500	1,120,000
Stock-based compensation expense	$ 1,000	$ 700	$ 1,817	$ 1,198
Income tax excess benefit	439	$ 38	$ 1,600	$ 300
Stock options exercised (in shares)			545,242	277,197
Total intrinsic value of options exercised			$ 7,600	$ 1,600
Unrecognized compensation cost related to unvested stock option	$ 13,700		$ 13,700
Weighted average period for unrecognized compensation cost			2 years 25 days