Pensions and Other Postretirement Benefits (Schedule of Net Pension and Other Retirement Plan Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 02, 2016	Jun. 27, 2015	Jul. 02, 2016	Jun. 27, 2015
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Net service cost	$ 104	$ 103	$ 206	$ 206
Interest cost	205	214	410	427
Expected return on plan assets	(166)	(163)	(333)	(326)
Amortization of actuarial losses	52	58	103	116
Net periodic benefit cost	195	212	386	423
Other Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Net service cost	25	19	50	38
Interest cost	33	30	65	60
Expected return on plan assets	0	0	0	0
Amortization of actuarial losses	19	19	38	38
Net periodic benefit cost	$ 77	$ 68	$ 153	$ 136