Property and Equipment - Table 3 (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of Depreciation Expense, Amortization Expense Relating to Assets Under Capital Lease Obligations, Interest Capitalized, and Rent Expense Under Operating Leases
Depreciation expense	$ 59.0	$ 52.5	$ 48.1
Amortization expense	10.1	11.1	12.1
Interest capitalized	1.0	0.5	0.4
Rent expense:
Minimum rent payments	41.2	38.5	39.9
Contingent and other rents	20.6	24.2	18.8
Other	4.5	4.2	4.7
Total rent expense	$ 66.3	$ 66.9	$ 63.4