Other Operating Expense, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
Other operating expense, net:
(Gain) loss on property, plant and equipment disposals	$ 0	$ (79)	$ 259	$ (187)
(Gain) loss on currency exchanges	88	85	85	530
Amortization of intangibles	76	76	229	229
Retirement expenses	27	83	102	173
Miscellaneous (income) expense	(50)	(34)	(150)	(61)
Other operating expense, net	$ 141	$ 131	$ 525	$ 684