Employee Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Employee Benefit Plans
Deferred compensation plan assets, noncurrent	$ 37,600	$ 33,200
Deferred compensation liability classified, noncurrent	$ 35,793	$ 33,220
Employer discretionary matching contribution made to 401(k) plan and non-qualified deferred compensation plan, percentage	2.10%	2.10%	1.50%
Maximum employee contribution percentage eligible for employer match	6.00%	6.00%	6.00%
Costs of 401(k) plan and non-qualified deferred compensation plan	$ 1,800	$ 1,500	$ 1,100