Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jun. 25, 2016	Jul. 01, 2017	Jun. 25, 2016
James Horwich [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	$ 251	$ 226	$ 477	$ 341
Robert E Shaw [Member]
Related Party Transaction [Line Items]
Ownership of Common Stock, Percentage	7.40%		7.40%
Voting Interest of Common Stock, Percentage	3.50%		3.50%
Related Party Transaction, Purchases from Related Party	$ 1,663	$ 1,859	$ 3,658	$ 3,634
Related Party Transaction, Purchases from Related Party, Percentage	2.10%	2.40%	2.40%	2.50%
Robert P Rothman [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	$ 67	$ 66	$ 135	$ 132