Revenues - Contract Assets and Liabilities (Details) $ in Thousands	3 Months Ended
	Mar. 28, 2020 USD ($)
Movement in Contract Assets and Liabilities [Roll Forward]
Unbilled revenue, beginning balance	$ 3,937
Increase in unbilled revenue	281
Unbilled revenue, ending balance	4,218
Contract liability, beginning balance	4,561
Increase in accrued customer advances	1,347
Contract liability, ending balance	$ 5,908