Lease Accounting (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	$ 4.1	$ 3.6	$ 8.1	$ 7.1
Finance lease cost
Amortization of leased assets	0.3	0.3	0.6	0.6
Interest on lease liabilities	0.0	0.0	0.1	0.1
Net lease costs	$ 4.4	$ 3.9	$ 8.8	$ 7.8