Financing Obligations (Details) $ in Millions	1 Months Ended	12 Months Ended
	Jun. 30, 2008 USD ($) term_extension_option	Dec. 31, 2017 monthly_payment	Dec. 31, 2015 USD ($) real_property	May. 19, 2008 real_property
Minimum Lease Payments, Sale Leaseback Transactions, Fiscal Year Maturity [Abstract]
2016			$ 5.0
2017			4.6
2018			5.2
2019			5.5
2020			5.9
Thereafter			69.8
Total minimum lease payments			96.0
Less: interest			(53.5)
Total financing obligations			42.5
Less: current portion			(0.1)
Long-term financing obligations			$ 42.4
Sale Leaseback Transaction Agreement for Properties
Sale Leaseback Transaction [Line Items]
Parcels of real property under sale leaseback transaction | real_property				181
Master Lease Agreement
Sale Leaseback Transaction [Line Items]
Parcels of real property under sale leaseback transaction | real_property			181
Gross proceeds of sale leaseback transaction	$ 337.2
Sale leaseback initial term	20 years
Number of options to extend initial leaseback term | term_extension_option	4
Extension period for options to extend sale leaseback initial term (in years)	5 years
Properties assigned to franchisee or released from lessor | real_property			152
Reduction in property and equipment and financing obligations as a result of sales transactions			$ 277.2
Forecast
Minimum Lease Payments, Sale Leaseback Transactions, Fiscal Year Maturity [Abstract]
Number of Monthly Obligation Payments in Fiscal Year | monthly_payment		11