Customer Financing (Detail)	3 Months Ended
	Jul. 25, 2020 USD ($) finance_agreement	Jul. 27, 2019 USD ($)	Apr. 25, 2020 USD ($)
Customer Financing [Line Items]
Maximum credit financed for equipment purchases for any one customer	$ 1,000,000
Number of customer financing contracts | finance_agreement	2
Financing contracts sold	$ 50,070,000	$ 66,303,000
(Loss) gain on sale of financing contracts	(2,386,000)	(1,478,000)
Cash and cash equivalents	119,561,000		$ 77,944,000
Current receivables of finance contracts not yet sold	20,675,000		21,391,000
Finance contracts receivable sold and outstanding	617,503,000
Deferred purchase price	252,178,000		228,019,000
Noncash investments acquired	$ 201,861,000	87,710,000
Bad debt write-offs, percentage (less than)	1.00%
Customer Finance Contracts
Customer Financing [Line Items]
(Loss) gain on sale of financing contracts	$ (342,000)	7,346,000
Noncash investments acquired	16,511,000	$ 1,475,000
Unsettled Financing Arrangements
Customer Financing [Line Items]
Cash and cash equivalents	$ 28,615,000		$ 21,830,000
The Bank of Tokyo-Mitsubishi UFJ, Ltd.
Customer Financing [Line Items]
Percentage of principal amount of financing contracts held as collateral (at least)	9.50%
Capacity under agreement	$ 525,000,000
Fifth Third Bank
Customer Financing [Line Items]
Percentage of principal amount of financing contracts held as collateral (at least)	20.00%
Capacity under agreement	$ 100,000,000