Schedule of Assumptions, Net Periodic Benefit Costs (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.80%	3.90%
Expected long-term rate of return on assets	3.60%	3.70%
Rates of annual increase in compensation levels		3.00%
Other Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate		3.90%