Benefit Plans - Components of Accumulated Other Comprehensive Loss (Gain) (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Pension
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service cost	$ 0	$ 0
Unrecognized net actuarial loss (gain)	10,346	12,300
Total accumulated other comprehensive loss (gain)	10,346	12,300
Post-retirement
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service cost	0	0
Unrecognized net actuarial loss (gain)	(3,621)	(7,425)
Total accumulated other comprehensive loss (gain)	$ (3,621)	$ (7,425)