v3.6.0.2
Postretirement Benefit Plans - Summary of Weighted Average Assumptions Used to Calculate Projected Benefit Obligations (Detail)
Dec. 31, 2016
Dec. 31, 2015
Pension and Other Postretirement Benefit Expense [Abstract]    
Discount rate 2.00% 2.50%
Rate of compensation increase 1.90% 2.20%