Other Operating Income And Expenses (Details) $ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2012 USD ($)	Aug. 31, 2014 USD ($)	Aug. 31, 2013 USD ($) store
Property Subject to or Available for Operating Lease [Line Items]
Carrying value of assets at time of sale	$ 38.4
Proceeds from sale	$ 29.7	$ 8.7
2013 Company Drive-In Closures Member
Property Subject to or Available for Operating Lease [Line Items]
Loss on closure of Company Drive-Ins			$ 2.4
Number of Restaurants | store			12