Pension Information - Components of Net Periodic Pension Benefit (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Compensation And Retirement Disclosure [Abstract]
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	128	125	256	250
Expected return on plan assets	(256)	(273)	(512)	(546)
Other components	147	143	294	286
Net periodic pension benefit (cost)	$ 19	$ (5)	$ 38	$ (10)