Pension and Employee Benefit Plans - Schedule of Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Compensation And Retirement Disclosure [Abstract]
Net loss	$ 3,287	$ 527	$ 271
Amortization of net actuarial gain	(266)	(263)	(238)
Total recognized in other comprehensive income (loss)	3,021	264	33
Total recognized in net periodic benefit cost and other comprehensive income (loss)	$ 2,727	$ 576	$ (50)