Employee Benefits - Pension and Other Defined Contribution Retirement Plan Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Pension Plans [Member] | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost for benefits earned	$ 596	$ 698	$ 1,192	$ 1,395
Interest cost on projected benefit obligation	4,790	4,561	9,580	9,122
Expected return on plan assets	(7,740)	(9,246)	(15,479)	(18,492)
Net amortization and deferrals	1,549	1,793	3,098	3,585
Net periodic benefit income	(805)	(2,194)	(1,609)	(4,390)
Total expense	2,276	330	4,162	389
Pension Plans [Member] | Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost for benefits earned	4,470	5,610	8,939	11,220
Interest cost on projected benefit obligation	4,338	3,911	8,675	7,822
Expected return on plan assets	(12,032)	(12,334)	(24,064)	(24,668)
Net amortization and deferrals	2,972	3,988	5,943	7,977
Net periodic benefit income	(252)	1,175	(507)	2,351
Total expense	1,454	2,791	2,751	5,264
Defined Contribution and Other Retirement Plans [Member] | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined contribution and other retirement plans	3,081	2,524	5,771	4,779
Defined Contribution and Other Retirement Plans [Member] | Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined contribution and other retirement plans	$ 1,706	$ 1,616	$ 3,258	$ 2,913