Employee Benefit Plans - Funded Status of Defined Benefit Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Noncurrent pension asset	$ 2,593	$ 1,037
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Balance at beginning of the year	54,261	57,086
Interest cost	2,072	2,302	$ 2,376
Participant contributions	5	6
Actuarial losses (gains)	596	292
Settlement gain	(315)
Change in currency exchange rates	908	(1,804)
Benefits paid	(3,549)	(3,621)
Benefit obligations at end of the year	53,978	54,261	57,086
Fair value at beginning of the year	42,268	44,067
Actual return on plan assets	3,726	3,278
Employer contributions	1,006	565
Participant contributions	5	6
Change in currency exchange rates	766	(2,027)
Benefits paid	(3,549)	(3,621)
Fair value of plan assets at end of year	44,222	42,268	44,067
Funded status	(9,756)	(11,993)
Noncurrent pension asset	2,593	1,037
Current	(155)	(156)
Noncurrent	(12,194)	(12,874)
Amounts recognized in the Consolidated Balance Sheets	(9,756)	(11,993)
Accumulated other comprehensive loss - actuarial losses, net	30,435	32,514
Total	20,679	20,521
Accumulated benefit obligations (ABO)	53,978	54,261
OPEB
Defined Benefit Plan Disclosure [Line Items]
Balance at beginning of the year	2,744	3,238
Interest cost	78	96	108
Actuarial losses (gains)	(279)	(263)
Benefits paid	(330)	(327)
Benefit obligations at end of the year	2,213	2,744	$ 3,238
Funded status	(2,213)	(2,744)
Current	(367)	(434)
Noncurrent	(1,846)	(2,310)
Amounts recognized in the Consolidated Balance Sheets	(2,213)	(2,744)
Accumulated other comprehensive loss - actuarial losses, net	616	679
Accumulated other comprehensive income (loss)	$ 616	$ 679