Revenue Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Apr. 01, 2018
Disaggregation of Revenue
Franchise rental income	$ 58,452	$ 50,107
Total revenues	408,583	380,564
United States
Disaggregation of Revenue
Franchise rental income	50,665	44,265
Total revenues	384,730	359,635
Canada
Disaggregation of Revenue
Franchise rental income	7,787	5,842
Total revenues	18,207	16,337
Other International
Disaggregation of Revenue
Franchise rental income	0	0
Total revenues	5,646	4,592
Sales at Company-operated restaurants
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	167,697	153,649
Sales at Company-operated restaurants | United States
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	167,697	153,649
Sales at Company-operated restaurants | Canada
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Sales at Company-operated restaurants | Other International
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Franchise royalty revenue
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	94,843	89,943
Franchise royalty revenue | United States
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	84,378	80,222
Franchise royalty revenue | Canada
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	5,508	5,363
Franchise royalty revenue | Other International
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	4,957	4,358
Franchise fees
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	7,110	7,965
Franchise fees | United States
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	6,009	7,085
Franchise fees | Canada
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	412	646
Franchise fees | Other International
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	689	234
Advertising funds revenue
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	80,481	78,900
Advertising funds revenue | United States
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	75,981	74,414
Advertising funds revenue | Canada
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	4,500	4,486
Advertising funds revenue | Other International
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	$ 0	$ 0