Income Taxes - Operating Loss and Tax Credit Carryforwards (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Charitable contribution carryover (CCCs)	$ 32.9	$ 39.6
Interest limitation carryover (ILC)	0.0	10.6
US State
Operating Loss Carryforwards [Line Items]
Net operating losses	165.7	355.7
Tax credit carryforwards	5.3	8.0
US Federal
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	12.2	12.2
Foreign
Operating Loss Carryforwards [Line Items]
Net operating losses	$ 36.9	$ 57.0