Employee Benefits - Amounts Recognized in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 20,810	$ 19,336
Prior service cost (credit)	(25,330)	(31,664)
Total AOCI (before tax effects)	(4,520)	(12,328)
U.S Plans [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	136,888	154,417
Prior service cost (credit)	194	141
Total AOCI (before tax effects)	137,082	154,558
Non-U.S. Plans [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	338,916	339,654
Prior service cost (credit)	(7,635)	(7,390)
Total AOCI (before tax effects)	$ 331,281	$ 332,264