Leases - Operating Leases on Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 27, 2020	Dec. 28, 2019
Leases
Operating lease right-of-use assets, net	$ 35,925	$ 38,698
Current portion of operating lease liabilities	10,946	9,813
Long-term operating lease liabilities, net of current portion	28,003	31,997
Total operating lease liabilities	$ 38,949	$ 41,810