Income Taxes Income Tax - Unrecognized tax benefits additional information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 12.5
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	3.9	$ 1.7
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	0.6	$ 0.8	$ 0.3
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	$ 2.0
Domestic Tax Authority
Income Taxes [Line Items]
Year Which Prior Year's Tax Returns Are No Longer Subject to Tax Examination	Dec. 31, 2015
State and Local Jurisdiction
Income Taxes [Line Items]
Year Which Prior Year's Tax Returns Are No Longer Subject to Tax Examination	Dec. 31, 2015