v2.4.0.6
Fair Value Measurements (Details) (USD $)
In Millions, unless otherwise specified
Oct. 27, 2012
item
Jul. 28, 2012
Fair Value Measurements [Abstract]    
Investments in ARS 1  
Book value, available-for-sale investments $ 2.9  
Par value, available-for-sale investments 3.9  
Amount by which fair value of available-for-sale securities is lower than cost basis $ 1.0 $ 1.2