Segments - Long Lived Assets, Excluding Financial Instruments and Tax Assets, Classified by Controlling Countries over Ten Percent (Detail) - USD ($) $ in Thousands		Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Segment Reporting Information [Line Items]
Long-lived assets		$ 305,899	$ 337,805	$ 131,505
UNITED STATES
Segment Reporting Information [Line Items]
Long-lived assets	[1]	182,218	199,436	98,455
United Kingdom
Segment Reporting Information [Line Items]
Long-lived assets		34,081	35,739	6,466
Other Countries
Segment Reporting Information [Line Items]
Long-lived assets		$ 89,600	$ 102,630	$ 26,584

[1] Includes Corporate long-lived assets