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Pension And Other Postretirement Benefit Plans - Additional Information (Detail) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 6 Months Ended
Oct. 27, 2012
Oct. 29, 2011
Oct. 27, 2012
Oct. 29, 2011
Pension and Other Postretirement Benefit Plans [Line Items]        
Pension expense $ 842 $ 589 $ 1,587 $ 1,105
Company contributions for postretirement plan $ 38 $ 38 $ 75 $ 75