Provision for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Provision for Income Taxes
Income tax expense (benefit)	$ 20.7	$ 20.0	$ 69.5	$ 30.0
Effective tax rates (as a percent)	19.00%	26.60%	25.40%	25.00%
Unrecognized tax benefits, excluding penalties and interest	$ 34.8		$ 34.8		$ 22.7
Accrued interest and penalties related to uncertain tax positions	2.3		2.3		$ 1.8
Penalties and interest (benefit) expense relating to unrecognized tax benefits	$ 0.2	$ 0.1	$ 0.6	$ 0.4
Statutory tax rate (as a percent)			21.00%
Change in tax rate - foreign jurisdictions (as a percent)			5.50%
Germany
Provision for Income Taxes
Statutory tax rate (as a percent)			30.00%
Switzerland
Provision for Income Taxes
Statutory tax rate (as a percent)			20.00%