Summary of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 25, 2013	Dec. 26, 2012	Dec. 28, 2011
Concentration Risk [Line Items]
Short-term investments	$ 5.3	$ 11.8
Net gain/(loss) on investments (less than $0.1 million in 2011)	1.1	0.7	(0.1)
Deferred compensation plan investments	8.2	6.4
Cash overdrafts	1.6	6.3
Maximum self-insurance retention levels, minimum per individual claim	0.5
Maximum self-insurance retention levels, maximum per individual claim	1.0
Discounted insurance liabilities	23.8	23.2
Self insurance liabilities, discount rate	1.00%	1.00%
Undiscounted insurance liabilities	24.4	23.8
Revenue recognized in breakage on gift cards	0.3	0.3
Initial franchise fees	1.6	3.0	3.1
Deferred fees	1.1	1.2
Advertising expense	11.7	13.4	16.1
Advertising contributions from franchisees	$ 66.6	$ 65.1	$ 60.5
Revenue from franchises and licenses risk [Member]
Concentration Risk [Line Items]
Franchise revenue, percentage	32.00%	32.00%	34.00%