Pension Plan Weighted Average Asset Allocations (Detail)	Dec. 31, 2015	Dec. 31, 2014
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items]
Defined benefit plan securities	100.00%	100.00%
Equity Securities
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items]
Defined benefit plan securities	46.00%	51.00%
Debt Securities
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items]
Defined benefit plan securities	48.00%	49.00%
Cash/Other
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items]
Defined benefit plan securities	6.00%	0.00%