v3.7.0.1
Employee Benefits - Additional Information (Detail)
$ in Billions
 3 Months Ended
Mar. 31, 2017
USD ($)
Mar. 31, 2016
USD ($)
plan
Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]      
Number of defined benefit pension plans | plan   7  
Amount paid in severance benefits over the period $ 0.2    
Post employment benefits liability 0.5    
Weighted Average      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate assumption   4.21% 4.60%
Pension      
Defined Benefit Plan Disclosure [Line Items]      
Pension remeasurement credit (charge)   $ 0.2  
Qualified pension plans      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan contributions by employer 3.6    
Defined benefit plan discretionary contributions by employer 3.4    
Minimum expected cash contribution to qualified pension benefits plan 0.6    
Expected cash contribution to qualified pension benefits plan $ 4.0