Leases - Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Leases [Abstract]
Operating lease cost	$ 3.1	$ 3.1	$ 6.2	$ 6.3
Short-term lease cost	0.1	0.2	0.3	0.4
Variable lease cost	0.8	0.9	1.6	1.5
Total lease cost	$ 4.0	$ 4.2	$ 8.1	$ 8.2