Debt and Other Financing Arrangements - Debt Maturity Schedule (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2015
Debt Instrument [Line Items]
Capital Leases, Future Minimum Payments Due, Next Twelve Months	$ 17.4
Long-Term Debt, Excluding Capital Leases, Current	6.0
Long-Term Debt, Excluding Capital Leases, Repayments of Principal in Year Two	6.0
Long-Term Debt, Excluding Capital Leases, Repayments of Principal in Year Three	6.0
Long-Term Debt, Excluding Capital Leases, Repayments of Principal in Year Four	6.0
Long-Term Debt, Excluding Capital Leases, Repayments of Principal in Year Five	6.0
Long-Term Debt, Excluding Capital Leases, Repayments of Principal After Year Five	1,655.2
Long-Term Debt, Excluding Capital Leases, Gross	1,685.2
Capital Leases, Future Principal Payments Due, Repayments of Principal in Next Twelve Months	12.4
Capital Leases, Future Principal Payments Due in Two Years	12.0
Capital Leases, Future Principal Payments Due in Three Years	9.4
Capital Leases, Future Principal Payments Due in Four Years	6.5
Capital Leases, Future Principal Payments Due in Five Years	4.9
Capital Leases, Future Principal Payments Due Thereafter	37.7
Capital Leases, Future Minimum Principal Payments Due	82.9
Debt Instrument, Unamortized Discount	0.0
Debt Issuance Costs, Net	0.0
Long-term Debt and Capital Lease Obligations, Repayments of Principal in Next Twelve Months	18.4
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Two	18.0
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Three	15.4
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Four	12.5
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal in Year Five	10.9
Long-term Debt and Capital Lease Obligations, Maturities, Repayments of Principal after Year Five	1,692.9
Long-term Debt, Gross	1,768.1
Net unamortized premium	1.9	$ 8.5
Debt Issuance Costs, Noncurrent, Net	22.3
Long-Term Debt, Excluding Capital Leases, Net	1,664.8
Debt and Capital Lease Obligations	1,747.7	1,206.6
Capital Leases, Future Minimum Payments Due in Two Years	16.4
Capital Leases, Future Minimum Payments Due in Three Years	13.2
Capital Leases, Future Minimum Payments Due in Four Years	9.9
Capital Leases, Future Minimum Payments Due in Five Years	7.8
Capital Leases, Future Minimum Payments Due Thereafter	49.0
Capital Lease Obligations Retained After Sale of Business, Affiliate and Productive Assets			$ 54.5
Long-Term Debt, Less Current Portion [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Noncurrent, Net	$ 22.3	$ 11.9