Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2023	Apr. 30, 2022	Apr. 30, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance, Shares	16,570,619
Beginning Balance	$ 772,883	$ 756,238	$ 711,450
Net income (loss)	93,723	(29,722)	61,193
Other comprehensive income (loss), net of tax	147	64,793	(3,395)
Stock-based compensation	7,396	4,708	4,598
Exercise of stock-based compensation awards, net of amounts withheld for taxes	(1,199)	(1,072)	(1,351)
Stock repurchases		(25,000)	(20,000)
Employee benefit plan contributions	$ 838	$ 2,938	3,743
Ending Balance, Shares	16,635,295	16,570,619
Ending Balance	$ 873,788	$ 772,883	$ 756,238
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance, Shares	16,570,619	16,801,101	16,926,537
Beginning Balance	$ 363,224	$ 362,524	$ 359,430
Stock-based compensation	$ 7,396	$ 4,708	$ 4,598
Exercise of stock-based compensation awards, net of amounts withheld for taxes, shares	47,576	29,808	29,019
Exercise of stock-based compensation awards, net of amounts withheld for taxes	$ (1,199)	$ (1,072)	$ (1,351)
Stock repurchases, shares		(299,781)	(200,046)
Stock repurchases		$ (5,874)	$ (3,896)
Employee benefit plan contributions, shares	17,100	39,491	45,591
Employee benefit plan contributions	$ 838	$ 2,938	$ 3,743
Ending Balance, Shares	16,635,295	16,570,619	16,801,101
Ending Balance	$ 370,259	$ 363,224	$ 362,524
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	399,434	448,282	403,193
Net income (loss)	93,723	(29,722)	61,193
Stock repurchases		(19,126)	(16,104)
Ending Balance	493,157	399,434	448,282
Accumulated Other Comprehensive Loss [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	10,225	(54,568)	(51,173)
Other comprehensive income (loss), net of tax	147	64,793	(3,395)
Ending Balance	$ 10,372	$ 10,225	$ (54,568)