Customer Financing (Details)	3 Months Ended
	Jul. 30, 2016 USD ($) finance_agreement	Aug. 01, 2015 USD ($)	Apr. 30, 2016 USD ($)	Apr. 25, 2015 USD ($)
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 under ASC 860	$ 109,594,000	$ 94,767,000
Revenues from Sale of Financing Contracts	10,185,000	5,887,000
Cash and cash equivalents	89,978,000	$ 186,440,000	$ 137,453,000	$ 347,260,000
Current receivables of finance contracts not yet sold	68,280,000		87,406,000
Unearned income	1,303,000		1,768,000
Finance contracts receivable sold and outstanding	629,326,000
Deferred purchase price	$ 158,284,000		108,837,000
Bad debt write-offs, percentage (less than)	1.00%
Unsettled Financing Arrangements [Member]
Customer Financing [Line Items]
Cash and cash equivalents	$ 26,183,000		$ 27,186,000
The Bank of Tokyo-Mitsubishi UFJ, Ltd. [Member]
Customer Financing [Line Items]
Percentage of principal amount of financing contracts held as collateral (at least)	9.00%
Capacity under agreement	$ 575,000,000
Fifth Third Bank [Member]
Customer Financing [Line Items]
Percentage of principal amount of financing contracts held as collateral (at least)	10.00%
Capacity under agreement	$ 100,000,000