Weighted Average Assumptions Used In Determining Pension Plan Information (Detail) - Pension Plans, Defined Benefit	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Cost
Discount rate - service cost	4.26%	3.79%	4.58%
Discount rate - interest cost	3.47%	3.79%	4.58%
Expected return on plan assets	6.72%	7.17%	7.26%
Rate of compensation increase	3.57%	3.42%	3.49%
Benefit Obligation
Discount rate	3.91%	4.03%	3.79%
Rate of compensation increase	3.58%	3.57%	3.42%