Annual report pursuant to Section 13 and 15(d)

Income Taxes - Narrative (Details)

v3.8.0.1
Income Taxes - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Dec. 31, 2017
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Operating Loss Carryforwards [Line Items]          
Tax expense resulting from remeasurement of deferred tax balances $ 0.8        
Undistributed earnings of foreign subsidiaries 8.7 $ 8.7      
Increase in valuation allowance 11.7        
Future annual required taxable income for state tax purposes   190.8      
Unrecognized tax benefits 4.8 4.8 $ 5.0 $ 81.9 $ 76.1
Unrecognized tax benefits that would impact effective tax rate 0.3 0.3      
Unrecognized tax benefit that would impact effective tax rate, net of federal tax benefits $ 0.2 0.2      
Decrease to prior period tax positions related to Tax Cuts and Jobs Act of 2017   0.5      
Decrease resulting from prior period tax positions   $ 0.6 $ 78.2