Long-term Debt - Receivables Facility (Details) (Receivables Facility [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Receivables Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Unused Borrowing Capacity, Fee percentage	0.40%	0.45%	0.40%	0.45%
Secured Debt	$ 58.5		$ 58.5		$ 18.0
Secured debt, Maximum Borrowing Capacity	105.0		105.0
Debt Instrument, Basis Spread on Variable Rate	1.20%	1.50%	1.20%	1.50%
Receivables facility debt available but not utilized	33.4		33.4		51.9
Receivables facililty, debt aggregate costs	$ 0.4	$ 0.2	$ 0.7	$ 0.5
Average liquidation period, Receivables pool	1.5		1.5
Average discount rate, Receivables facility	1.80%		1.80%