Revenue from Contracts with Customers - Revenues Disaggregated by Revenue Source and Market (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2022	Jun. 30, 2021	Jun. 29, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Total revenue	$ 124,111	$ 121,985	$ 234,159	$ 229,706
Core Market
Disaggregation of Revenue [Line Items]
Total revenue	109,622	106,599	206,795	200,286
Non-Core Market
Disaggregation of Revenue [Line Items]
Total revenue	14,489	15,386	27,364	29,420
Company-operated restaurant revenue
Disaggregation of Revenue [Line Items]
Total revenue	106,454	106,970	200,411	201,131
Company-operated restaurant revenue | Core Market
Disaggregation of Revenue [Line Items]
Total revenue	101,440	99,429	191,066	186,652
Company-operated restaurant revenue | Non-Core Market
Disaggregation of Revenue [Line Items]
Total revenue	5,015	7,541	9,345	14,478
Franchise revenue
Disaggregation of Revenue [Line Items]
Total revenue	10,064	8,389	19,319	16,001
Franchise revenue | Core Market
Disaggregation of Revenue [Line Items]
Total revenue	4,708	4,086	9,058	7,773
Franchise revenue | Non-Core Market
Disaggregation of Revenue [Line Items]
Total revenue	5,357	4,304	10,262	8,229
Franchise advertising fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	7,593	6,626	14,429	12,574
Franchise advertising fee revenue | Core Market
Disaggregation of Revenue [Line Items]
Total revenue	3,474	3,084	6,671	5,861
Franchise advertising fee revenue | Non-Core Market
Disaggregation of Revenue [Line Items]
Total revenue	$ 4,117	$ 3,541	$ 7,757	$ 6,713