Annual report pursuant to Section 13 and 15(d)

Segments - Additional Information (Detail)

v3.20.2
Segments - Additional Information (Detail) - Segment
12 Months Ended
Apr. 30, 2020
Apr. 30, 2019
Apr. 30, 2018
Segment Reporting Information [Line Items]      
Number of global business segments 4    
Geographic Concentration Risk | Sales Revenue, Net [Member] | UNITED STATES | Minimum      
Segment Reporting Information [Line Items]      
Concentration risk percentage 10.00% 10.00% 10.00%
Geographic Concentration Risk | Sales Revenue, Net [Member] | United Kingdom | Minimum      
Segment Reporting Information [Line Items]      
Concentration risk percentage 10.00% 10.00% 10.00%
Geographic Concentration Risk | Long-Lived Assets | UNITED STATES | Minimum      
Segment Reporting Information [Line Items]      
Concentration risk percentage 10.00% 10.00% 10.00%
Geographic Concentration Risk | Long-Lived Assets | United Kingdom | Minimum      
Segment Reporting Information [Line Items]      
Concentration risk percentage 10.00% 10.00% 10.00%