Employee Benefit Plans - Recognized Net Periodic Benefit Cost and Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Service cost	$ 74	$ 87	$ 103
Interest cost	89	83	114
Net amortization of transition obligation and actuarial loss	23	84	192
Net periodic benefit cost	186	254	409
Net gain	(518)	(404)	(808)
Amortization	(23)	(84)	(192)
Total recognized in other comprehensive income	(541)	(488)	(1,000)
Total recognized in net periodic benefit cost and other comprehensive income	$ (355)	$ (234)	$ (591)