Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan [Abstract]
Service cost	$ 26	$ 50	$ 38
Interest cost	54	62	46
Expected return on plan assets	(16)	(18)	(11)
Curtailments	95	0	0
Amortization of prior service cost	67	69	69
Amortization of net transition obligation	0	0	22
Amortization of plan loss	17	20	0
Net periodic pension benefit cost	$ 243	$ 183	$ 164