Leases - Lease Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Leases [Abstract]
Operating lease expense	$ 14.3	$ 14.1	$ 28.5	$ 28.8
Finance lease expense amortization of leased assets	0.2	0.3	0.2	0.6
Short-term and variable lease expense	0.2	0.0	0.3	0.1
Sublease income	(0.1)	(0.1)	(0.2)	(0.2)
Total	$ 14.6	$ 14.3	$ 28.8	$ 29.3