Pensions and Other Post-Retirement Benefits - Weighted Average Assumptions Underlying Pension Computations (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension benefit obligation:
Pension benefit obligation - discount rate	2.50%	3.20%	2.80%
Pension benefit obligation - rate of compensation increase	1.20%	1.70%	2.00%
Net periodic pension costs:
Net periodic pension costs - discount rate	3.20%	2.80%	4.10%
Net periodic pension costs - rate of compensation increase	1.70%	2.00%	2.10%
Net periodic pension costs - expected long-term return on plan assets	5.10%	6.00%	6.00%