Leases - Lease Maturity (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2019	$ 9.3
2020	18.6
2021	17.5
2022	14.8
2023	12.3
Thereafter	80.9
Total future minimum lease payments	153.4
Less imputed interest	(27.6)
Total operating lease liability	$ 125.8	$ 0.0	[1]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019		18.7
2020		18.6
2021		17.5
2022		14.7
2023		12.3
Thereafter		80.1
Total future minimum lease payments		$ 161.9

[1] Derived from audited consolidated financial statements.