Fair Value Fair Value of Debt (Details) - Fair Value, Inputs, Level 2 [Member] - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Reported Value Measurement [Member] | Revolving Credit Facility [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Line of credit facility, amount outstanding	$ 0.0	$ 0.0
Reported Value Measurement [Member] | Term Loan A [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	92.5	0.0
Reported Value Measurement [Member] | Term Loan B [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	1,526.8	0.0
Reported Value Measurement [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
Reported Value Measurement [Member] | 6.625% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	550.0	550.0
Reported Value Measurement [Member] | 6.50% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	500.0	0.0
Reported Value Measurement [Member] | 6.25% Notes due 2025 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	700.0	0.0
Reported Value Measurement [Member] | 6.25% Notes due 2021 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	400.0	400.0
Reported Value Measurement [Member] | 5.125% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	0.0	200.0
Estimate of Fair Value Measurement [Member] | Revolving Credit Facility [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Line of credit facility, amount outstanding	0.0	0.0
Estimate of Fair Value Measurement [Member] | Term Loan A [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	92.5	0.0
Estimate of Fair Value Measurement [Member] | Term Loan B [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	1,528.7	0.0
Estimate of Fair Value Measurement [Member] | 7.75% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	217.5	221.0
Estimate of Fair Value Measurement [Member] | 6.625% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	570.2	566.1
Estimate of Fair Value Measurement [Member] | 6.50% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	527.5	0.0
Estimate of Fair Value Measurement [Member] | 6.25% Notes due 2025 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	736.8	0.0
Estimate of Fair Value Measurement [Member] | 6.25% Notes due 2021 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	410.0	412.0
Estimate of Fair Value Measurement [Member] | 5.125% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	$ 0.0	$ 201.7