Employee Benefit Plans (Defined Contribution Plans) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Non-Collective-Bargaining Plan [Member]
Defined Contribution Plans [Line Items]
Percentage of Employees Covered	85.00%
Employer Matching Contribution, Percentage	1.00%
Employer Matching Contribution, Discretionary Percentage	2.00%
Maximum Annual Contribution Per Employee, Percentage	3.00%
Cost Recognized	$ 264	$ 233
Collective-Bargaining Plan [Member]
Defined Contribution Plans [Line Items]
Percentage of Employees Covered	15.00%
Maximum Annual Contribution Per Employee, Percentage	2.75%
Cost Recognized	$ 29	$ 18