Components of Lease Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Operating lease expense	$ 24.6	$ 23.2	$ 71.9	$ 65.3
Amortization of Right-of-Use Assets	0.4	0.1	1.1	0.4
Finance Lease, Interest Expense	0.1	0.1	0.4	0.3
Variable lease expense	$ 1.9	$ 3.2	$ 6.5	$ 11.4