Leases - Components of Lease Expense (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Operating lease cost:
Amortization of right-of-use assets	$ 0.8	$ 2.1
Interest on lease liabilities	0.1	0.4
Total operating lease cost	$ 0.9	$ 2.5