Income Taxes Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation Allowance [Line Items]
Interest Related to Uncertain Tax Positions	$ (4.1)	$ 0.7	$ 0.7
Reduction In General And Administrative Expense Due To Uncertain Tax Positions Realized	$ 2.5
Federal statutory income tax rate	21.00%	21.00%	35.00%
Operating Loss Carryforwards, Valuation Allowance	$ 98.8	$ 82.3
Alternative Minimum Tax Credit Refund Received	73.9
Alternative minimum tax	37.1	126.0
Unrecognized Tax Benefits	0.0	$ 19.0	$ 19.0
Future Years [Member]
Valuation Allowance [Line Items]
Alternative minimum tax	74.6
2019 [Member]
Valuation Allowance [Line Items]
Alternative minimum tax	$ 37.5