Supplemental Disclosures to Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 02, 2018	Jan. 03, 2017	Dec. 29, 2015
Class of Stock [Line Items]
Interest paid (net of amounts capitalized)	$ 3,482	$ 2,394	$ 839
Income taxes (refunded) paid	(158)	(427)	354
Changes in purchases of property and equipment accrued in accounts payable, net	(842)	(1,431)	(1,414)
Common Stock [Member] | Class A Common Stock [Member]
Class of Stock [Line Items]
Convertible Preferred Stock, Shares Issued Upon Conversion, Value	$ 18,500	$ 0	$ 0