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Employee Benefit Plans (Pension Plans With Accumulated Benefit Obligations In Excess Of Fair Value Of Plan Assets) (Details) - USD ($)
$ in Thousands
Dec. 27, 2015
Dec. 28, 2014
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]    
Projected benefit obligation $ 93,349 $ 116,949
Accumulated benefit obligation 88,442 110,204
Fair value of plan assets $ 2,801 $ 3,557