Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Operating leases:
Operating lease right-of-use assets	$ 46.8	$ 48.0
Operating lease liabilities (component of other current liabilities)	13.4	12.0
Operating lease liabilities, noncurrent	35.7	39.1
Operating lease, liability	$ 49.1	$ 51.1
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Finance leases:
Property, plant and equipment	$ 52.9	$ 52.9
Accumulated depreciation	(8.6)	(5.8)
Property, plant and equipment, net	44.3	47.1
Current portion of long-term debt	2.2	2.1
Long-term debt	43.4	45.6
Total finance lease liability	$ 45.6	$ 47.7
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent	us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtAndCapitalLeaseObligations	us-gaap:LongTermDebtAndCapitalLeaseObligations
Weighted-average remaining lease term (in years):
Operating leases	7 years	6 years
Finance leases	17 years	18 years
Weighted-average discount rate:
Operating leases	4.40%	4.70%
Finance leases	5.90%	5.20%