Retirement Plans Net Periodic Pension Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 25, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit)			$ 0
Defined Benefit Plan, Service Cost		$ 44	84	$ 230
Defined Benefit Plan, Interest Cost		1,230	1,171	1,159
Defined Benefit Plan, Future Amortization of Gain (Loss)			336
Defined Benefit Plan, Amortization of Gains (Losses)		535	$ 328	430
Defined Benefit Plan, Net Periodic Benefit Cost		$ 1,809		$ 1,583	$ 1,819
Discount rate		4.20%	4.80%	4.00%
Rate of compensation increase		3.00%	3.00%	3.00%
Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Interest Cost	$ 1,216
Defined Benefit Plan, Net Periodic Benefit Cost	$ 1,552