Employee Benefit Plans (Weighted-Average Actuarial Assumptions Used to Determine Benefit Obligations) (Detail)	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Pension Plans
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Defined benefit pension plans, Discount rate	3.85%	4.31%
Unfunded Supplemental Benefit Plans
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Defined benefit pension plans, Discount rate	4.03%	4.33%