Benefit Plans (Schedule of Net Defined Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jul. 01, 2016	Jun. 30, 2017	Jul. 01, 2016
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Service cost	$ 115	$ 110	$ 225	$ 218
Interest cost	40	45	78	88
Amortization of net loss	19	47	36	93
Expected return on plan assets	(6)	(4)	(10)	(9)
Net defined benefit cost	$ 168	$ 198	$ 329	$ 390