Significant Accounting Policies - Summary of Estimated Useful Lives (Detail)	12 Months Ended
	Apr. 30, 2019
Minimum | Building and improvements
Property Plant And Equipment [Line Items]
Estimated useful life	10 years
Minimum | Software and hardware
Property Plant And Equipment [Line Items]
Estimated useful life	2 years
Minimum | Machinery and equipment
Property Plant And Equipment [Line Items]
Estimated useful life	2 years
Maximum | Building and improvements
Property Plant And Equipment [Line Items]
Estimated useful life	40 years
Maximum | Software and hardware
Property Plant And Equipment [Line Items]
Estimated useful life	7 years
Maximum | Machinery and equipment
Property Plant And Equipment [Line Items]
Estimated useful life	10 years