Pension and Post-Retirement Benefit Plans - Schedule of Components of Net Periodic Pension Cost (Detail) - Pension Plans [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefit earned during the period	$ 321	$ 317
Interest cost on projected benefit obligation	1,862	2,343
Expected return on plan assets	(2,272)	(2,718)
Amortization of prior service cost	72	74
Amortization of actuarial loss	1,062	1,419
Net periodic pension cost	$ 1,045	$ 1,435