Summary of Significant Accounting Policies - Supplemental Cash Flow Items (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016
Supplemental Disclosures of Cash Flow Information
Interest paid	$ 1,535	$ 2,081
Taxes paid	0	0
Non-cash activities:
Purchases of property and equipment not paid	$ 3,065	$ 215