Accounts Receivable Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
Changes to allowance for doubtful accounts
Balance at beginning of period	$ 94	$ 106	$ 219
Charges (Reductions) to Expense	87	229	17
(Write-offs) Collections	(21)	(241)	(130)
Balance at end of period	$ 160	$ 94	$ 106