Accounting Standards Adopted and Newly Issued Accounting Standards Not Yet Adopted - Reclassified franchise and restaurant revenues and expenses (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Franchise expenses	$ 78,341	$ 70,033		$ 243,157	$ 209,721
Company restaurant expenses	0	17		0	7,807
Franchisor [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer, excluding assessed Tax	162,078	142,579		469,332	450,367
Food and Beverage [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer, excluding assessed Tax	$ 0	0		$ 0	7,518
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Franchise and restaurant revenues		112,347			358,912
Franchise and Restaurant Expenses		41,800			123,476
Franchise expenses		41,783			115,669
Company restaurant expenses		17			7,807
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Franchisor [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer, excluding assessed Tax		$ 112,347			351,394
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Food and Beverage [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer, excluding assessed Tax			$ 0		$ 7,518