Retirement Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2016	Sep. 27, 2015	Sep. 25, 2016	Sep. 27, 2015	Dec. 27, 2015
Defined Benefit Plan Disclosure [Line Items]
Cash Surrender Value of Life Insurance	$ 7,400		$ 7,400		$ 6,900
Benefits Payable, Age	65
Benefits paid			1,200
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year			1,600
Service cost	$ 0	$ 11	0	$ 33
Interest cost	304	307	912	923
Net amortization	84	134	252	401
Net periodic pension cost	$ 388	$ 452	$ 1,164	$ 1,357