Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2020	Dec. 28, 2019
Leases [Abstract]
Operating lease expense	$ 7,468	$ 6,985
Short-term lease expense	136	142
Variable lease expense	1,574	1,286
Total lease expense	$ 9,178	$ 8,413