Income Taxes Income Tax - Unrecognized tax benefits additional information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 12.9
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	4.9	$ 3.9
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	0.9	$ 0.6	$ 0.8
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	$ 2.3
Domestic Tax Authority
Income Taxes [Line Items]
Open Tax Year	2016
State and Local Jurisdiction
Income Taxes [Line Items]
Open Tax Year	2016