Stock Incentive and Purchase Plans (Schedule of Performance-Based and Market-Based Restricted Stock and Restricted Stock Units Activity Rollforward) (Details) (Performance-based restricted stock and restricted stock unit and market-based awards [Member], USD $)	12 Months Ended
	Apr. 26, 2013	Apr. 27, 2012	Apr. 29, 2011
Performance-based restricted stock and restricted stock unit and market-based awards [Member]
Non-vested shares, beginning of year	464,125
Granted, shares	8,982
Vested, shares	(76,946)
Forfeited, shares	0
Non-vested shares, end of year	396,161	464,125
Weighted Average Grant Date Fair Value, beginning of year	$ 25.36
Weighted Average Grant Date Fair Value, Granted	$ 50.10	$ 25.23	$ 0.00
Weighted Average Grant Date Fair Value, Vested	$ 27.34
Weighted Average Grant Date Fair Value, Forfeited	$ 0
Weighted Average Grant Date Fair Value, end of year	$ 25.54	$ 25.36