Leases - Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Loans and Leases Receivable Disclosure [Line Items]
Variable lease cost	$ 4,524	$ 4,529	$ 12,228	$ 12,619
Sublease income	(114)	(162)	(342)	(483)
Amortization of right-of-use assets	221	414	1,103	1,248
Interest on lease liabilities	26	69	108	204
Total lease cost	30,954	29,954	90,621	79,751
Restaurant Rent Expense [Member]
Loans and Leases Receivable Disclosure [Line Items]
Operating lease cost	26,126	24,933	77,088	65,770
General and Administrative Expense [Member]
Loans and Leases Receivable Disclosure [Line Items]
Operating lease cost	$ 171	$ 171	$ 436	$ 393