Employee Benefit Plans and Stock-based Compensation - Summary of Projected Benefit Obligation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2020	Sep. 27, 2019	Sep. 25, 2020	Sep. 27, 2019
Employee Benefit and Share-based Payment Arrangement, Noncash Expense [Abstract]
Service cost	$ 65	$ 57	$ 187	$ 171
Interest cost	9	20	27	59
Net periodic benefit cost	$ 74	$ 77	$ 214	$ 230