Employee Benefits - Sensitivity of Disclosures to Changes in Selected Assumptions (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
25 BP Decrease in Discount Rate, Change in ABO	$ 2,454
25 BP Decrease in Discount Rate, Change in pension expense	75
U.S. Pension Plans [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
25 BP Decrease in Discount Rate, Change in PBO	16,777
25 BP Decrease in Discount Rate, Change in ABO	16,698
25 BP Decrease in Discount Rate, Change in pension expense	(148)
25 BP Decrease in Long-Term Rate of Return, Change in pension expense	1,249
Non-U.S. Plans [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
25 BP Decrease in Discount Rate, Change in PBO	49,150
25 BP Decrease in Discount Rate, Change in ABO	47,394
25 BP Decrease in Discount Rate, Change in pension expense	2,677
25 BP Decrease in Long-Term Rate of Return, Change in pension expense	$ 1,941