Long-term Debt - Receivables Facility (Details) (Receivables Facility [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Receivables Facility [Member]
Debt Instrument [Line Items]
Secured debt, Maximum Borrowing Capacity	$ 90.0		$ 90.0
Debt cost, 3-month LIBOR plus	1.50%	3.25%	1.50%	3.25%
Debt Instrument, Unused Borrowing Capacity, Fee percentage	0.45%	0.50%	0.45%	0.50%
Receivables facility debt outstanding	0		0		0
Receivables facility debt available but not utilized	90.0		90.0		57.6
Receivables tacililty, debt aggregate costs	$ 0.2	$ 0.5	$ 0.5	$ 0.9
Average liquidation period, Receivables pool	1.6		1.6
Average discount rate, Receivables facility	1.70%		1.70%