Customer Financing - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 26, 2014 Customer	Apr. 27, 2013	Apr. 28, 2012	Apr. 30, 2011
Customer Financing [Line Items]
Maximum credit financed for equipment purchases for any one customer	$ 500
Number of customer financing contracts	2
Financing contracts sold under ASC 860	282,698	283,175	287,627
Current receivables of finance contracts not yet sold	63,236	64,272
Cash and cash equivalents	264,908	505,228	573,781	388,665
Unearned income	5,894	1,586
Finance contracts receivable sold and outstanding	496,906
Deferred purchase price	84,750	72,328
Bad debt write-offs, percentage, maximum	1.00%
The Bank of Tokyo-Mitsubishi UFJ, Ltd. [Member]
Customer Financing [Line Items]
Maximum holdback receivable	500,000
Fifth Third Bank [Member]
Customer Financing [Line Items]
Maximum holdback receivable	100,000
Unsettled Financing Arrangements [Member]
Customer Financing [Line Items]
Cash and cash equivalents	$ 28,152	$ 34,260
Minimum [Member] | The Bank of Tokyo-Mitsubishi UFJ, Ltd. [Member]
Customer Financing [Line Items]
Percentage of principal amount of financing contracts held as collateral	9.00%
Minimum [Member] | Fifth Third Bank [Member]
Customer Financing [Line Items]
Percentage of principal amount of financing contracts held as collateral	10.00%