Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2016	Sep. 27, 2015	Sep. 25, 2016	Sep. 27, 2015	Dec. 27, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 175,580	$ 175,656	$ 544,354	$ 533,325
Property, plant and equipment, net	227,586		227,586		$ 234,646
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	27,338	41,935	95,407	127,431
Property, plant and equipment, net	39,907		39,907		44,274
MEXICO
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	148,242	$ 133,721	448,947	$ 405,894
Property, plant and equipment, net	$ 187,679		$ 187,679		$ 190,372