Commitments and Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Operating Leases, Rent Expense	$ 54.6	$ 51.0	$ 49.3
Operating Leases, Future Minimum Payments Due	$ 210.0	$ 210.4	$ 213.2