Defined Contribution Plan, Pension and Other Post-Retirement Benefit Plans - Fair Value of Pension Plan Assets Measured Using Significant Unobservable Inputs (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Change in plan assets:
Fair value of plan assets — Beginning of the year	$ 73,386
Fair value of plan assets at end of the year	74,366	$ 73,386
Level 3
Change in plan assets:
Fair value of plan assets — Beginning of the year	10,962	10,153
Actual return on assets held at reporting date	430	809
Purchases, sales and settlements, net	(7,322)	0
Fair value of plan assets at end of the year	$ 4,070	$ 10,962