Debt and Financing - Schedule of Debt and Additional Information (Details) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2018	Dec. 31, 2018 USD ($)
Debt Instrument [Line Items]
Par Value	$ 884.5
Discount	(7.3)
Debt Issuance Costs	(6.7)
Book Value	870.5
Book Value, Current Maturities	(23.6)		$ (20.7)
Par Value, Excluding Current Maturities	860.9
Premium (Discount)	(7.3)
Book Value, Excluding Current Maturities	846.9		854.2
Book Value
Debt Instrument [Line Items]
Long-term debt, fair value	870.5		874.9
Fair value
Debt Instrument [Line Items]
Long-term debt, fair value	877.4		850.7
2014 ABL Facility Credit Agreement
Debt Instrument [Line Items]
Total cash and cash equivalents and Managed Accessibility	155.7		203.8
Managed Accessibility	9.1		1.2
Changes to restricted cash	20.0		(25.0)
Term Loan
Debt Instrument [Line Items]
Par Value	573.0
Discount	(7.3)
Debt Issuance Costs	(6.0)
Book Value	559.7
Par Value, Current Maturities	(18.0)
Discount, Current Maturities	0.0
Deferred Issuance Costs, Current	0.0
Book Value, Current Maturities	$ (18.0)
Average Effective Interest Rate	11.60%
Term Loan | Book Value
Debt Instrument [Line Items]
Long-term debt, fair value	$ 559.7		559.4
Term Loan | Fair value
Debt Instrument [Line Items]
Long-term debt, fair value	569.5		546.0
ABL Facility | 2014 ABL Facility Credit Agreement
Debt Instrument [Line Items]
Par Value	0.0
Discount	0.0
Debt Issuance Costs	0.0
Book Value	0.0
Line of credit facility, total cash and availability	48.1
Secured Second A&R CDA
Debt Instrument [Line Items]
Par Value	26.8
Discount	0.0
Debt Issuance Costs	(0.1)
Book Value	$ 26.7
Average Effective Interest Rate	8.00%
Unsecured Second A&R CDA
Debt Instrument [Line Items]
Par Value	$ 46.7
Discount	0.0
Debt Issuance Costs	(0.2)
Book Value	46.5
Par Value, Current Maturities	(1.5)
Discount, Current Maturities	0.0
Deferred Issuance Costs, Current	0.0
Book Value, Current Maturities	$ (1.5)
Average Effective Interest Rate	8.00%
Lease financing obligations
Debt Instrument [Line Items]
Par Value	$ 238.0
Discount	0.0
Debt Issuance Costs	(0.4)
Book Value	237.6
Par Value, Current Maturities	(4.1)
Discount, Current Maturities	0.0
Deferred Issuance Costs, Current	0.0
Book Value, Current Maturities	$ (4.1)
Average Effective Interest Rate	15.10%
Lease financing obligations | Book Value
Debt Instrument [Line Items]
Long-term debt, fair value	$ 237.6		242.2
Lease financing obligations | Fair value
Debt Instrument [Line Items]
Long-term debt, fair value	234.9		234.7
Other Debt Obligations | Book Value
Debt Instrument [Line Items]
Long-term debt, fair value	73.2		73.3
Other Debt Obligations | Fair value
Debt Instrument [Line Items]
Long-term debt, fair value	$ 73.0		$ 70.0
Term Loan Agreement
Debt Instrument [Line Items]
Maximum Total Leverage Ratio, March 31, 2019	3.25
Maximum Total Leverage Ratio, June 30, 2019	3.25
Maximum Total Leverage Ratio, September 30, 2019	3.25
Maximum Total Leverage Ratio, December 31, 2019	3.00
Maximum Total Leverage Ratio, March 31, 2020	3.00
Maximum Total Leverage Ratio, June 30, 2020	3.00
Maximum Total Leverage Ratio, September 30, 2020	2.75
Maximum Total Leverage Ratio, December 31, 2020	2.75
Maximum Total Leverage Ratio, March 31, 2021	2.75
Maximum Total Leverage Ratio, June 30, 2021 and thereafter	2.50
Total leverage ratio		2.76
London Interbank Offered Rate (LIBOR) | Term Loan
Debt Instrument [Line Items]
Floor interest rate	1.00%
Basis spread on variable rate	8.50%