Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Tax Contingency [Line Items]
Income before income taxes	$ 86.1	$ 77.8	$ 114.4	$ 122.3
Income tax provision	$ 24.9	$ 31.6	$ 32.8	$ 45.0
Effective tax rate	28.90%	40.60%	28.70%	36.80%
Cumulative impact of cost sharing for stock-based compensation			$ 18.2
Reduction of income tax reserves			(15.2)
Interest benefit included within reduction of income tax reserves			1.7
Unrecognized tax benefits	$ 152.7		152.7
Minimum
Income Tax Contingency [Line Items]
Unrecognized tax benefits could decrease up to	23.0		23.0
Maximum
Income Tax Contingency [Line Items]
Unrecognized tax benefits could decrease up to	$ 44.0		$ 44.0