Supplemental Financial Information - Accounts Receivable (Details) - USD ($) $ in Thousands	Sep. 29, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 3,366	$ 3,503
Delivery program receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	1,784	636
Insurance receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	157	744
Vendor rebate receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	611	788
Franchise receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	517	527
Other receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 297	$ 808