Stock Incentive and Purchase Plans (Summary Of Stock Option Activity) (Details) (USD $)	9 Months Ended
	Jan. 25, 2013
Stock Incentive and Purchase Plans [Abstract]
Outstanding - beginning of period, shares	1,441,057
Granted, shares	216,802
Execised, shares	(466,232)
Forfeited, shares	(14,131)
Expired, shares	(1,267)
Outstanding - end of period, shares	1,176,229
Fully vested and exercisable - end of period, shares	608,752
Fully vested and expected to vest - end of period, shares	1,142,951	[1]
Weighted Average Exercise Price, beginning of period	$ 23.75
Weighted Average Exercise Price, Granted	$ 43.34
Weighted Average Exercise Price, Exercised	$ 24.07
Weighted Average Exercise Price, Forfeited	$ 27.41
Weighted Average Exercise Price, Expired	$ 36.87
Weighted Average Exercise Price, end of period	$ 27.18
Weighted Average Exercise Price, Fully vested and excercisable - end of period	$ 23.35
Weighted Average Exercise Price, Fully vested and expected to vest - end of period	$ 26.98	[1]
Weighted Average Remaining Contractual Term, Outstanding - end of period	6 years 4 months 13 days
Weighted Average Remaining Contractual Term - Fully vested and exercisable - end of period	4 years 6 months 4 days
Weighted Average Remaining Contractual Term - Fully vested and expected to vest - end of period	6 years 3 months 15 days	[1]
Aggregate Intrinsic Value, Outstanding - end of period	$ 18,975,803	[2]
Aggregate Intrinsic Value, Fully vested and exercisable - end of period	12,260,480	[2]
Aggregate Intrinsic Value, Fully vested and expected to vest - end of period	$ 18,666,528	[1],[2]

[1] Fully vested and expected to vest factors in expected forfeitures.

[2] The intrinsic value of an option at January 25, 2013 is the difference between the fair market value of the underlying stock using the market closing stock price and the option exercise price for an in-the-money option.