Leases (Summary of Supplemental Balance Sheet Information Related to Operating Leases) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019
Leases [Abstract]
Lease right-of-use assets	$ 35.2	$ 29.2
Current lease liabilities	5.1
Lease non-current liabilities	$ 30.1
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent