Summary of Significant Accounting Policies - Life Insurance Policies (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 26, 2020 USD ($)	Jul. 02, 2021 USD ($) Individual	Jun. 26, 2020 USD ($)	Dec. 31, 2020 USD ($)
Supplementary Information For Corporate Owned Life Insurance [Line Items]
Number of former employees covered under insurance policies | Individual		16
Average age of former employees covered under insurance policies		78 years
Gross cash surrender values of life insurance		$ 27,600		$ 27,100
Loans on cash surrender value		25,000		24,400
Net cash surrender values of life insurance		3,883		3,587
Gross death benefit of life insurance contracts		35,800		35,000
Life insurance proceeds to be received upon the death of participants		10,500
Non-taxable life insurance gain	$ 389		$ 389
Payments for Loans			1,900
Casualty Events [Member]
Supplementary Information For Corporate Owned Life Insurance [Line Items]
Non-taxable life insurance gain		7,900	$ 400
Non-Qualified Defined Benefit Executive Supplemental Benefit Plan [Member]
Supplementary Information For Corporate Owned Life Insurance [Line Items]
Net cash surrender values of life insurance		$ 2,600		$ 2,700