Retirement Plans - Schedule of Net Benefit Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Compensation And Retirement Disclosure [Abstract]
Interest cost	$ 251	$ 286	$ 502	$ 572
Net amortization	72	52	144	104
Net periodic pension cost	$ 323	$ 338	$ 646	$ 676