Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ 28.9	$ 10.8	$ 2.1
State	3.4	2.4	3.3
International	46.0	30.5	35.1
Current income tax provision	78.3	43.7	40.5
Deferred:
Federal and state	0.2	10.3	1.4
International	(6.0)	5.0	(0.5)
Deferred income tax provision	(5.8)	15.3	0.9
Income tax expense	$ 72.5	$ 59.0	$ 41.4