Supplemental Disclosures to Condensed Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
	Oct. 02, 2018	Oct. 03, 2017
Class of Stock [Line Items]
Interest paid (net of amounts capitalized)	$ 3,006	$ 3,028
Income taxes paid (refunded)	49	(158)
Changes in purchases of property and equipment accrued in accounts payable, net	1,346	2,144
Common Stock | Common Class A
Class of Stock [Line Items]
Conversion of Series A convertible preferred stock to common stock	$ 0	$ 18,500