Pension Plans - Components of Net Periodic Pension Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Compensation And Retirement Disclosure [Abstract]
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	289	325	853	976
Expected return on plan assets	(585)	(563)	(1,757)	(1,688)
Recognized net actuarial loss	163	98	461	348
Net periodic pension benefit	$ (133)	$ (140)	$ (443)	$ (364)