Defined Benefit Pension Plans - Pension Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2022	Jan. 31, 2021
Retirement Benefits [Abstract]
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	177	181	531	543
Expected return on plan assets	(401)	(321)	(1,203)	(963)
Recognition of net loss	136	428	406	1,285
Net periodic pension (income) expense	$ (88)	$ 288	$ (266)	$ 865