Leases - Components of Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Leases [Abstract]
Operating lease cost	$ 2.0	$ 1.8
Short-term lease cost	0.2	0.3
Amortization of leased assets	0.5	0.4
Interest on lease liabilities	0.1	0.1
Total lease cost	$ 2.8	$ 2.6