Leases - Components of Lease Expenses (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 costs	$ 12.4	$ 13.9	$ 24.3	$ 27.6
Variable lease costs	2.1	2.4	4.8	4.7
Sublease income	(0.8)	(0.9)	(1.6)	(1.8)
Operating lease expense	$ 13.7	$ 15.4	$ 27.5	$ 30.5