Benefit Plans (Schedule of Net Defined Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Sep. 29, 2017	Sep. 30, 2016
Defined Benefit Plan [Abstract]
Service cost	$ 120	$ 108	$ 345	$ 326
Interest cost	42	44	120	132
Amortization of net loss	19	47	55	140
Expected return on plan assets	(5)	(5)	(15)	(14)
Net defined benefit cost	$ 176	$ 194	$ 505	$ 584