Employee Benefits - Percentage of Assets Invested (Detail) - Pension Plan [Member]	Dec. 31, 2017	Dec. 31, 2016
U.S Plans [Member] | Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of assets invested	1.00%	0.00%
U.S Plans [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of assets invested	28.00%	36.00%
U.S Plans [Member] | Fixed income [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of assets invested	71.00%	64.00%
U.S Plans [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of assets invested	0.00%	0.00%
U.S Plans [Member] | Alternative and other investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of assets invested	0.00%	0.00%
Non-U.S. Plans [Member] | Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of assets invested	4.00%	2.00%
Non-U.S. Plans [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of assets invested	27.00%	27.00%
Non-U.S. Plans [Member] | Fixed income [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of assets invested	40.00%	56.00%
Non-U.S. Plans [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of assets invested	4.00%	5.00%
Non-U.S. Plans [Member] | Alternative and other investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of assets invested	25.00%	10.00%