Leases - Future Minimum Lease Payments (Details) $ in Millions	Mar. 31, 2019 USD ($)
Operating leases
2019 (excluding the three months ended March 31, 2019)	$ 18.2
2020	19.2
2021	13.8
2022	9.4
2023	7.4
Thereafter	18.1
Total undiscounted lease payments	86.1
Imputed interest	(6.5)
Total lease liabilities	79.6
Finance leases
2019 (excluding the three months ended March 31, 2019)	0.1
2020	0.1
2021	0.1
2022	0.1
Total undiscounted lease payments	0.4
Total lease liabilities	$ 0.4