Amortization Expense of Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 26, 2014	Sep. 27, 2013	Sep. 26, 2014	Sep. 27, 2013
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense – cost of sales	$ 1,614	$ 1,343	$ 4,529	$ 3,937
Amortization expense – operating expenses	2,843	1,772	7,463	5,625
Total amortization expense	$ 4,457	$ 3,115	$ 11,992	$ 9,562