Long-term Debt - Receivables Facility (Details) (Receivables Facility [Member], USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013
Debt Instrument [Line Items]
Secured debt, Maximum Borrowing Capacity	$ 105.0	$ 105.0
Debt cost, 3-month LIBOR plus	1.00%
Debt Instrument, Unused Borrowing Capacity, Fee percentage		0.35%	0.40%
Debt Instrument, Maturity Date		Oct. 16, 2018	Oct. 12, 2017
Receivables facility debt outstanding	78.7	78.7	57.0		57.0
Receivables facility debt available but not utilized	1.6	1.6	20.2		20.2
Receivables facililty, debt aggregate costs		$ 1.3	$ 1.4	$ 1.3
Average liquidation period, Receivables pool		1.7
Average discount rate, Receivables facility	1.80%	1.80%
Minimum [Member]
Debt Instrument [Line Items]
Debt cost, 3-month LIBOR plus					1.20%
Maximum [Member]
Debt Instrument [Line Items]
Debt cost, 3-month LIBOR plus			1.35%