Segments - Fee Revenue Classified by Country (Detail) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2024	Apr. 30, 2023	Apr. 30, 2022
Segment Reporting Information [Line Items]
Total revenue	$ 2,795,505	$ 2,863,836	$ 2,643,455
Fee revenue
Segment Reporting Information [Line Items]
Total revenue	2,762,671	2,835,408	2,626,718
Fee revenue | U.S.
Segment Reporting Information [Line Items]
Total revenue	1,507,819	1,568,119	1,348,377
Fee revenue | Other countries
Segment Reporting Information [Line Items]
Total revenue	$ 1,254,852	$ 1,267,289	$ 1,278,341