Retirement Plans and Other Post-Retirement Benefits - Schedule of Net Periodic Benefit Cost of Pension and Other Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Pension settlement charge	$ 75,326
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,300	$ 2,300	$ 2,000
Interest cost	11,500	13,300	13,700
Expected return on plan assets	(13,700)	(21,100)	(22,200)
Amortization of prior service cost	200
Amortization of actuarial loss	2,800	7,100	7,100
Termination benefits	1,300
Pension settlement charge	75,300
Total net periodic benefit cost	78,700	1,600	600
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		100	100
Interest cost	300	500	400
Amortization of actuarial loss	(900)	(300)
Total net periodic benefit cost	$ (600)	$ 300	$ 500