Accounting Policies - Reclassifications Out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Other income (expense), net	$ 2,586	$ 4,811
Income tax expense	(26,124)	(27,461)
Interest expense, net	(20,284)	(19,858)
Net income	87,457	72,004
Reclassification out of Accumulated Other Comprehensive Income | Pension and post retirement benefit plans
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Other income (expense), net	718	818
Income tax expense	(198)	(226)
Net income	520	592
Reclassification out of Accumulated Other Comprehensive Income | Amortization of initial net obligation and prior service cost
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Other income (expense), net	(375)	(422)
Reclassification out of Accumulated Other Comprehensive Income | Amortization of net loss
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Other income (expense), net	1,093	1,240
Reclassification out of Accumulated Other Comprehensive Income | Derivative contracts
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Income tax expense	(231)	(163)
Interest expense, net	679	589
Net income	$ 448	$ 426