Employee Benefit Plans (Amounts Recognized in Accumulated Other Comprehensive Income, Not Yet Recognized as a Component of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	Dec. 27, 2017	Dec. 28, 2016
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Unamortized actuarial losses, net	$ 0	$ 0
Other Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Unamortized actuarial losses, net	(1,092)	$ (1,033)
Maximum [Member] | Other Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive income to be recognized in 2018	$ 100