Supplemental Guarantor Information -Condensed Consolidating Statements of Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Supplemental Guarantor Information [Line Items]
Comprehensive income	$ 35.2	$ (34.3)	$ 48.0	$ (34.1)
Parent Guarantor [Member]
Supplemental Guarantor Information [Line Items]
Comprehensive income	35.2	(34.3)	48.0	(34.1)
Subsidiary Issuer [Member]
Supplemental Guarantor Information [Line Items]
Comprehensive income	35.2	(34.3)	48.0	(34.1)
Guarantor Subsidiaries [Member]
Supplemental Guarantor Information [Line Items]
Comprehensive income	95.8	92.2	169.2	162.8
Non-Guarantor Subsidiaries [Member]
Supplemental Guarantor Information [Line Items]
Comprehensive income	1.4	(5.1)	5.2	0.2
Co-Issuer [Member]
Supplemental Guarantor Information [Line Items]
Comprehensive income	0	0	0	0
Consolidating Adjustments [Member]
Supplemental Guarantor Information [Line Items]
Comprehensive income	(132.4)	(52.8)	(222.4)	(128.9)
Consolidated [Member]
Supplemental Guarantor Information [Line Items]
Comprehensive income	$ 35.2	$ (34.3)	$ 48.0	$ (34.1)