Schedule of Accumulated Benefit Obligation in Excess of Plan Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Compensation And Retirement Disclosure [Abstract]
Projected benefit obligation	$ 91,654	$ 90,247
Accumulated benefit obligation	91,109	89,024
Fair value of plan assets	$ 59,625	$ 56,790