Summary of Significant Accounting Policies - Supplemental Cash Flow Items (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Supplemental Disclosures of Cash Flow Information
Interest paid	$ 3,523	$ 3,984
Taxes paid	33	5
Non-cash activities:
Purchases of property and equipment not paid	$ 464	$ 2,124