Stock-Based Compensation - Summary of Stock Option Activity (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Apr. 26, 2014		Apr. 27, 2013		Apr. 28, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options, Beginning balance	721		986		1,273
Number of Options, Granted	57		56		64
Number of Options, Exercised	(345)		(290)		(232)
Number of Options, Canceled	(44)		(31)		(119)
Number of Options, Ending balance	389		721		986
Exercise Price, Beginning balance	$ 35.03	[1]	$ 31.45	[1]	$ 29.82	[1]
Number of Options, Vested or expected to vest at end of year	306
Exercise Price, Granted	$ 39.33	[1]	$ 34.10	[1]	$ 33.90	[1]
Number of Options, Exercisable at end of year	113
Exercise Price, Exercised	$ 35.73	[1]	$ 22.49	[1]	$ 24.11	[1]
Exercise Price, Canceled	$ 33.11	[1]	$ 33.79	[1]	$ 29.64	[1]
Exercise Price, Ending balance	$ 35.29	[1]	$ 35.03	[1]	$ 31.45	[1]
Exercise Price, Vested or expected to vest at end of year	$ 35.89	[1]
Exercise Price, Exercisable at end of year	$ 40.75	[1]
Intrinsic Value, Balance at end of year	$ 2,168
Intrinsic Value, Vested or expected to vest at end of year	1,667
Intrinsic Value, Exercisable at end of year	$ 498

[1] Weighted-average exercise price