Schedule of Assumptions, Net Benefit Obligation (Detail)	Dec. 31, 2018	Dec. 31, 2017
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.50%	3.80%
Rates of annual increase in compensation levels		3.00%
Other Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate		3.80%