Revenue from Contracts with Customers - Revenues Disaggregated by Revenue Source and Market (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 24, 2020	Jun. 26, 2019	Jun. 24, 2020	Jun. 26, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 99,604	$ 113,740	$ 204,767	$ 222,717
Core Market
Disaggregation of Revenue [Line Items]
Total revenue	86,962	95,788	179,026	187,310
Non-Core Market
Disaggregation of Revenue [Line Items]
Total revenue	12,642	17,952	25,741	35,407
Company-operated restaurant revenue
Disaggregation of Revenue [Line Items]
Total revenue	87,707	100,139	180,341	197,289
Company-operated restaurant revenue | Core Market
Disaggregation of Revenue [Line Items]
Total revenue	81,370	88,808	167,285	174,114
Company-operated restaurant revenue | Non-Core Market
Disaggregation of Revenue [Line Items]
Total revenue	6,337	11,331	13,056	23,175
Franchise revenue
Disaggregation of Revenue [Line Items]
Total revenue	6,719	7,918	13,781	14,362
Franchise revenue | Core Market
Disaggregation of Revenue [Line Items]
Total revenue	3,208	4,174	6,716	7,673
Franchise revenue | Non-Core Market
Disaggregation of Revenue [Line Items]
Total revenue	3,511	3,744	7,065	6,689
Franchise advertising fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	5,178	5,683	10,645	11,066
Franchise advertising fee revenue | Core Market
Disaggregation of Revenue [Line Items]
Total revenue	2,384	2,806	5,025	5,523
Franchise advertising fee revenue | Non-Core Market
Disaggregation of Revenue [Line Items]
Total revenue	$ 2,794	$ 2,877	$ 5,620	$ 5,543