Pensions and Other Post-retirement Benefits - Schedule of Assumptions Used to Determine Benefit Obligations and Net Periodic Benefit Cost (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Assumptions used to determine benefit obligations, average discount rate	3.92%	3.63%
Assumptions used to determine benefit obligations, rate of compensation increase	3.06%	3.03%
Assumptions used to determine net periodic benefit cost, average discount rate	3.63%	4.54%
Assumptions used to determine net periodic benefit cost, expected return on plan assets	8.17%	8.20%
Assumptions used to determine net periodic benefit cost, rate of compensation increases	3.03%	3.06%
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Assumptions used to determine benefit obligations, average discount rate	4.20%	3.85%
Assumptions used to determine net periodic benefit cost, average discount rate	3.85%	4.62%