Debt (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended									0 Months Ended									0 Months Ended					12 Months Ended	0 Months Ended										12 Months Ended
	Dec. 31, 2012	Dec. 31, 2010	Mar. 22, 2012	Dec. 31, 2011	Mar. 10, 2011	Dec. 16, 2010	Nov. 23, 2010	Nov. 23, 2010 Senior Credit Facility [Member]	Mar. 22, 2012 Amended Senior Credit Facility [Member]	Mar. 22, 2012 Revolving Credit Facility [Member]	Dec. 31, 2012 Revolving Credit Facility [Member]	Nov. 23, 2010 Revolving Credit Facility [Member]	Dec. 31, 2012 Letters of Credit [Member]	Mar. 22, 2012 Letters of Credit [Member]	Nov. 23, 2010 Letters of Credit [Member]	Dec. 31, 2012 Term Loan A [Member]	Mar. 22, 2012 Term Loan A [Member]	Nov. 23, 2010 Term Loan A [Member]	Mar. 10, 2011 Term Loan B [Member]	Dec. 31, 2012 Term Loan B [Member]	Mar. 22, 2012 Term Loan B [Member]	Nov. 23, 2010 Term Loan B [Member]	Dec. 31, 2012 Subordinated Debt [Member]	Dec. 31, 2012 ARC [Member]	Mar. 22, 2012 Through December 31, 2013 [Member]	Mar. 22, 2012 Through March 31, 2015 [Member]	Mar. 22, 2012 Thereafter [Member]	Mar. 10, 2011 Amended Senior Credit Facility [Member] Term Loan B [Member]	Dec. 31, 2012 Revolving Credit Facility [Member]	Dec. 31, 2012 Revolving Credit Facility [Member] Letters of Credit [Member]	Dec. 31, 2012 Securitization Facility [Member]	Dec. 31, 2012 Securitization Facility [Member] Letters of Credit [Member]	Dec. 31, 2012 International Subsidiary Letters Of Credit [Member]	Dec. 31, 2012 International Subsidiary Letters Of Credit [Member] Letters of Credit [Member]	Dec. 31, 2012 Minimum [Member] Amended Senior Credit Facility [Member]	Dec. 31, 2011 Minimum [Member] Amended Senior Credit Facility [Member]	Dec. 31, 2012 Maximum [Member] Amended Senior Credit Facility [Member]	Dec. 31, 2011 Maximum [Member] Amended Senior Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity			$ 1,050.0				$ 1,100.0	$ 1,050.0	$ 1,300.0	$ 250.0		$ 250.0		$ 150.0	$ 150.0		$ 250.0	$ 250.0			$ 800.0	$ 550.0									$ 100.0	$ 59.8	$ 17.3	$ 1.7
Additions to credit facility										250
Material pledge percentage			65.00%					65.00%
Bank, legal and other fees			8.1		1.6
Prepayment premium																			5.5
Interest coverage ratio	3.0
Required prepayment amount, percent of consolidated excess cash flow																																			25.00%		50.00%
Credit facility, covenant leverage ratio threshold																									4.5	4.0	3.75									2.0		2.5
Unamortized debt financing costs written off		3.8
LIBOR floor interest rate																			1.50%	1.00%								1.00%
Basis spread on LIBOR											3.00%								3.50%	3.00%								3.00%
Maturity date																			May 01, 2017									Mar. 01, 2018
Amount outstanding											0		71.7			237.5				788.5										14.7		56.7		0.8
Credit facility, remaining borrowing capacity																													235.3			3.1	15.6	0.9
Subordinated notes payable	100.6			98.3
Recovery Zone Facility bonds						35.0
Ownership interest																								100.00%
Letters of credit, amount outstanding																							$ 56.7											$ 0.3