Fair Value Fair Value of Debt (Details) (Fair Value, Inputs, Level 2 [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Line of Credit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	$ 0	$ 0
Carrying (Reported) Amount, Fair Value Disclosure [Member] | 9.25% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	337.5	379.0
Carrying (Reported) Amount, Fair Value Disclosure [Member] | 7.875% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	300.0	300.0
Carrying (Reported) Amount, Fair Value Disclosure [Member] | 7.75% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	200.0	200.0
Carrying (Reported) Amount, Fair Value Disclosure [Member] | 6.625% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	550.0	0
Carrying (Reported) Amount, Fair Value Disclosure [Member] | 5.25% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	0	249.9
Estimate of Fair Value, Fair Value Disclosure [Member] | Line of Credit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | 9.25% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	377.4	415.0
Estimate of Fair Value, Fair Value Disclosure [Member] | 7.875% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	310.1	295.5
Estimate of Fair Value, Fair Value Disclosure [Member] | 7.75% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	216.5	195.0
Estimate of Fair Value, Fair Value Disclosure [Member] | 6.625% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	555.5	0
Estimate of Fair Value, Fair Value Disclosure [Member] | 5.25% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	$ 0	$ 243.8