Annual report pursuant to Section 13 and 15(d)

Income Taxes, Tax Credits and Unrecognized Tax Benefits (Details)

v3.10.0.1
Income Taxes, Tax Credits and Unrecognized Tax Benefits (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Income Tax Disclosure [Abstract]      
Gross Unrecognized Tax Benefits, Including Interest $ 2.3 $ 2.3 $ 3.5
Reconciliation of the total amounts of unrecognized tax benefits [Roll Forward]      
Balance at January 1 2.1 3.4 4.7
Gross Increases - Tax Positions Prior Periods 0.6 0.1 0.3
Gross Decreases - Tax Positions Prior Periods (0.7) (0.2) (0.4)
Gross Increases - Current Period Tax Positions 0.4 0.4 0.5
Decreases - Settlements with Taxing Authorities (0.1) (0.5) 0.0
Reductions - Lapse of Statute of Limitations 0.0 (1.1) (1.7)
Balance at December 31 2.3 2.1 $ 3.4
Possible Decrease in Unrecognized Tax Benefits in 2017 1.0    
Tax Credit Carryforward [Line Items]      
Tax Credit Carryforward, Amount 57.8    
Tax Credit Carryforwards 55.9 $ 43.8  
Tax Credit Carryforward, Expiration Date 57.6    
Tax Credit Carryforwards, Not Subject to Expiration 0.2    
General Business Credits [Member]      
Tax Credit Carryforward [Line Items]      
Tax Credit Carryforwards 15.4    
State Tax Credits [Member]      
Tax Credit Carryforward [Line Items]      
Tax Credit Carryforwards $ 42.4