Annual report pursuant to Section 13 and 15(d)

Income Taxes - Schedule of Unrecognized Tax Benefits (Details)

v3.8.0.1
Income Taxes - Schedule of Unrecognized Tax Benefits (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]      
Unrecognized tax benefits, beginning balance $ 5.0 $ 81.9 $ 76.1
Gross change for current year positions 0.4 1.3 5.7
Decreases for prior period positions (0.6) (78.2)  
Increases for prior period positions     0.1
Unrecognized tax benefits, ending balance $ 4.8 $ 5.0 $ 81.9