Income Taxes Taxes by Jurisdiction (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018	Dec. 30, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Federal and state income taxes	$ (2,332)	$ (2,251)	$ 4,566	$ 1,284
Foreign income taxes	345	77	625	475
Income tax expense (benefit)	$ (1,987)	$ (2,174)	$ 5,191	$ 1,759
Effective income tax rate	18.50%		29.30%	35.10%
Unrecognized Tax Benefits	$ 4,200		$ 4,200		$ 4,300	$ 0