Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
James Horwich [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	$ 251	$ 226
Robert E Shaw [Member]
Related Party Transaction [Line Items]
Ownership of Common Stock, Percentage	7.30%
Voting Interest of Common Stock, Percentage	3.30%
Related Party Transaction, Purchases from Related Party	$ 1,715	$ 1,995
Related Party Transaction, Purchases from Related Party, Percentage	2.20%	2.80%
Robert P Rothman [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	$ 69	$ 67