Benefit Plans - Defined Benefit Pension Plan (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Compensation And Retirement Disclosure [Abstract]
Service cost – benefits earned during year	$ 568	$ 554
Interest cost on projected benefit obligation	1,121	1,298
Expected return on plan assets	(2,594)	(2,187)
Amortization of prior service cost	(9)	7
Amortization of net loss	793	799
Net periodic pension (income) cost	$ (121)	$ 471