Commitments and Contingencies - Future Minimum Lease Commitments Under Non-cancelable Operating Leases (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Q2 through Q4 2019	$ 18.5	$ 23.2
2020	19.6	17.6
2021	14.9	13.3
2022	12.3	11.1
2023	10.3	9.5
Thereafter	15.6	13.8
Total lease payments	91.2	$ 88.5
Less: imputed interest	(13.6)
Total	$ 77.6