Revenue from Contracts with Customers - Revenues Disaggregated by Revenue Source and Market (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 25, 2020	Mar. 27, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 105,163	$ 108,977
Core Market
Disaggregation of Revenue [Line Items]
Total revenue	92,065	91,522
Non-Core Market
Disaggregation of Revenue [Line Items]
Total revenue	13,098	17,455
Company-operated restaurant revenue
Disaggregation of Revenue [Line Items]
Total revenue	92,634	97,150
Company-operated restaurant revenue | Core Market
Disaggregation of Revenue [Line Items]
Total revenue	85,915	85,306
Company-operated restaurant revenue | Non-Core Market
Disaggregation of Revenue [Line Items]
Total revenue	6,719	11,844
Franchise revenue
Disaggregation of Revenue [Line Items]
Total revenue	7,062	6,444
Franchise revenue | Core Market
Disaggregation of Revenue [Line Items]
Total revenue	3,508	3,499
Franchise revenue | Non-Core Market
Disaggregation of Revenue [Line Items]
Total revenue	3,554	2,945
Franchise advertising fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	5,467	5,383
Franchise advertising fee revenue | Core Market
Disaggregation of Revenue [Line Items]
Total revenue	2,642	2,717
Franchise advertising fee revenue | Non-Core Market
Disaggregation of Revenue [Line Items]
Total revenue	$ 2,825	$ 2,666