Income Taxes Deferred Income Tax Asset and Liability Components - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation Allowance [Line Items]
Income tax provision at statutory rate, %	21.00%	21.00%	35.00%
Net deferred tax liability	$ 135.1	$ 89.8
Income taxes receivable	1.5	8.1
Gross domestic state net operating loss carryforwards	96.6
State tax credits	2.9
Deferred tax asset	6.8
Valuation allowance	4.5	$ 8.9
Deferred Tax Asset, Loss Carry Forwards
Valuation Allowance [Line Items]
Valuation allowance	$ 4.5