Income Taxes - Deferred Income Tax Assets and Liabilities and Valuation Allowances Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Tax Credit Carryforward [Line Items]
Deferred Tax Assets, Operating Loss and Tax Credit Carryforwards	$ 258.8	$ 220.3
Deferred Tax Assets, Operating Loss and Tax Credit Carryforwards, Not Subject to Expiration	101.5
Valuation allowance, deferred tax asset, increase (decrease), amount	25.4	16.0
Deferred Tax Assets, Valuation Allowance	196.0	183.3
Foreign Tax Authority [Member]
Tax Credit Carryforward [Line Items]
Valuation allowance, deferred tax asset, increase (decrease), amount	$ 12.8	$ 3.1