Leases - Components of Lease Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating lease cost:
Amortization of right-of-use assets	$ 1.1	$ 0.6
Interest on lease liabilities	0.3	0.1
Total operating lease cost	$ 1.4	$ 0.7