Defined Benefit Pension Plan and Postretirement Benefits - Benefit Obligations and Net Periodic Benefit Cost for Pension Plans (Detail)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	2.00%	2.00%	2.00%
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.00%	4.50%	4.30%
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.40%	4.90%	5.20%