Pension and Postretirement Benefits - Net Periodic Cost (Benefit) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Domestic Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 4,991	$ 5,259
Expected return on plan assets	(4,907)	(5,003)
Net periodic (benefit) cost	84	256
TCN Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	290	338
Expected return on plan assets	(345)	(397)
Net periodic (benefit) cost	$ (55)	$ (59)