Revenues - Disaggregation of Revenues (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) sale_channel segment	Mar. 25, 2020 USD ($)
Revenue from Contract with Customer [Abstract]
Number of sales channels | sale_channel	2
Number of segments | segment	1
Disaggregation of Revenue [Line Items]
Total operating revenue	$ 80,576	$ 96,695
Company restaurant sales
Disaggregation of Revenue [Line Items]
Total operating revenue	33,569	42,291
Royalties
Disaggregation of Revenue [Line Items]
Total operating revenue	20,844	23,847
Advertising revenue
Disaggregation of Revenue [Line Items]
Total operating revenue	14,111	17,526
Initial and other fees
Disaggregation of Revenue [Line Items]
Total operating revenue	1,838	1,697
Occupancy revenue
Disaggregation of Revenue [Line Items]
Total operating revenue	10,214	11,334
Franchise and license revenue
Disaggregation of Revenue [Line Items]
Total operating revenue	$ 47,007	$ 54,404