Pension and Postretirement Benefits - Components of Net Periodic Benefit Cost for Defined Benefit Pension Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Service cost	$ 523	$ 499	$ 63
Interest cost	17,421	15,846	18,772
Expected return on plan assets	(24,248)	(24,164)	(23,579)
Amortization of net actuarial loss	7,070	8,560	23,832
Net periodic benefit cost	$ 766	$ 741	$ 19,088