Leases - Aggregate lease maturities 2019 (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019
Finance Leases
2020	$ 8.9
2021	8.8
2022	5.1
2023	1.2
2024	0.5
Total lease payments, Finance leases	24.5
Less: Interest	1.4
Present value of lease liabilities	23.1
Operating Leases
2020	7.7
2021	6.9
2022	6.1
2023	4.5
2024	3.1
Thereafter	6.8
Total lease payments, Operating leases	35.1
Less: interest	(5.6)
Present value of lease liabilities	$ 29.5
Operating Lease, Liability, Statement of Financial Position	us-gaap:OperatingLeaseLiabilityCurrent us-gaap:OperatingLeaseLiabilityNoncurrent	us-gaap:OperatingLeaseLiabilityCurrent us-gaap:OperatingLeaseLiabilityNoncurrent
Total Finance and Operating Leases
2020	$ 16.6
2021	15.7
2022	11.2
2023	5.7
2024	3.6
Thereafter	6.8
Total lease payments	59.6
Less: interest	(7.0)
Present value of lease liabilities	$ 52.6