Debt - Credit Facility (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012
Line of Credit Facility [Line Items]
Receivables program maximum capacity	$ 103.5
Receivables facility, letters credit outstanding	23.2
Receivables facility remaining borrowing capacity	80.3
Line of credit facility, amount outstanding	0
Line of credit facility, remaining borrowing capacity	$ 210.0