Long-term Debt - Receivables Facility (Details) (Receivables Facility [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 17, 2012
Debt Instrument [Line Items]
Secured debt, Maximum Borrowing Capacity	$ 105.0		$ 90.0
Debt cost, 3-month LIBOR plus	1.20%	1.50%
Debt Instrument, Unused Borrowing Capacity, Fee percentage	0.40%	0.45%
Receivables facility debt outstanding	18.0	0
Receivables facility debt available but not utilized	51.9	57.6
Receivables tacililty, debt aggregate costs	$ 1.3	$ 1.6
Average liquidation period, Receivables pool	1 year 7 months
Average discount rate, Receivables facility	1.80%
Minimum [Member]
Debt Instrument [Line Items]
Debt cost, 3-month LIBOR plus	1.20%		1.50%
Debt Instrument, Unused Borrowing Capacity, Fee percentage			0.45%
Maximum [Member]
Debt Instrument [Line Items]
Debt cost, 3-month LIBOR plus	1.35%		1.75%
Debt Instrument, Unused Borrowing Capacity, Fee percentage	0.40%