Pension and Postretirement Benefits - Net Periodic Cost (Benefit) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Domestic Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 4,991	$ 5,293	$ 9,982	$ 10,552
Expected return on plan assets	(4,907)	(5,001)	(9,814)	(10,004)
Net periodic (benefit) cost	84	292	168	548
TCN Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	290	338	580	676
Expected return on plan assets	(345)	(397)	(690)	(794)
Net periodic (benefit) cost	$ (55)	$ (59)	$ (110)	$ (118)