Employee Benefit Plans (Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	Dec. 27, 2015	Dec. 28, 2014
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Prior service costs	$ 590	$ 421
Actuarial losses	24,810	42,718
Total	25,400	43,139
Deferred tax	(7,168)	(8,103)
Net	$ 18,232	$ 35,036