Revenue from Contracts with Customers - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 26, 2018	Dec. 27, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue allocated to loyalty points not redeemed	$ 900,000	$ 400,000
Loyalty rewards program, expected loyalty points redemption period (in years)	1 year
Franchise license
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Franchise agreement term (in years)	20 years
Franchise agreement renewal term (in years)	20 years
Hardware Services
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Unsatisfied performance obligations	$ 0
Minimum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Satisfied over renewal term (in years)	10 years
Maximum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Satisfied over renewal term (in years)	20 years
Accounting Standards Update 2014-09 | Retained Earnings
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative catch-up adjustment	$ 3,500,000