Leases - Components of Lease Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease cost	$ 6.8	$ 7.5
Short-term lease cost	1.6	1.2
Amortization of leased assets	1.6	1.5
Interest on lease liabilities	0.3	0.3
Total lease cost	$ 10.3	$ 10.5