Pension Plans - Components of Net Periodic Pension Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Compensation And Retirement Disclosure [Abstract]
Service cost	$ 130	$ 22	$ 225	$ 188
Interest cost	350	346	1,058	1,012
Expected return on plan assets	(483)	(612)	(1,459)	(1,603)
Recognized net actuarial loss	140	151	390	393
Net periodic pension cost (benefit)	$ 137	$ (93)	$ 214	$ (10)