XML 243 R78.htm IDEA: XBRL DOCUMENT v3.19.1
Pension plans - Additional Information (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]        
Net benefit obligations $ 40.0 $ 55.3    
Defined benefit pension charge (credit) (4.0) (3.4) $ 3.5  
Defined benefit pension (credit) charge (4.7) (4.2) 2.8  
Defined benefit plan, expected amortization, next fiscal year 2.3      
Defined benefit plan, expected amortization of gain (loss), next fiscal year 2.7      
Defined benefit plan, expected amortization of prior service credit 0.4      
Allowance included in benefit obligation 2.2 0.0    
Expected future employer contributions, next fiscal year 7.5      
Employer contribution amount 7.9      
U.S.        
Defined Benefit Plan Disclosure [Line Items]        
Payment for benefit settlement. annuities purchased     10.0  
Benefit liabilities settlement charge (credit), annuities purchased     0.1  
Payment for benefit settlement, lump sum paid     4.2  
Benefit liabilities settlement credit, lump sum paid     0.7  
Gross benefit amounts settled, annuities purchased     14.8  
Gross benefit amounts settled, lump sum paid     14.2  
U.K.        
Defined Benefit Plan Disclosure [Line Items]        
Net benefit obligations 31.8 43.4    
Defined benefit pension charge (credit) (4.1) (3.9) (1.5)  
Allowance included in benefit obligation 2.2 0.0    
Curtailment credit       $ 3.3
Past service credit       $ 14.9
Selling, General and Administrative Expenses        
Defined Benefit Plan Disclosure [Line Items]        
Defined benefit pension charge (credit) $ 0.7 $ 0.8 $ 0.7