Revenue from Contracts with Customers - Change in Contract Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2020	Dec. 25, 2019	Dec. 26, 2018
Loyalty reward program
Change in Contract with Customer, Liability [Roll Forward]
Contract with Customer, Liability	$ 1,084	$ 1,048	$ 425
Additional contract liability	2,463	2,395	1,850
Contract with Customer, Liability	900	1,084	1,048
Franchise revenue
Change in Contract with Customer, Liability [Roll Forward]
Contract with Customer, Liability	6,317	5,593
Revenue recognized - beginning balance	(1,082)	(441)
Additional contract liability	398	1,457
Revenue recognized - additional contract liability	(5)	(292)
Contract with Customer, Liability	$ 5,628	$ 6,317	$ 5,593