Leases (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating Leased Assets [Abstract]
Operating Leases, Future Minimum Payments Due, Current	$ 15.2
Operating Leases, Future Minimum Payments, Due in Two Years	17.3
Operating Leases, Future Minimum Payments, Due in Three Years	15.6
Operating Leases, Future Minimum Payments, Due in Four Years	14.3
Operating Leases, Future Minimum Payments, Due in Five Years	13.4
Operating Leases, Future Minimum Payments, Due Thereafter	59.0
Operating Leases, Rent Expense, Net	$ 20.9	$ 20.1	$ 22.7