Defined Contribution Plans, Pension and Other Post-Retirement Benefit Plans - Amounts Recognized as Other Changes in Plan Assets and Benefit Obligations in Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
U.S. Pension and Other Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain)	$ (1,087)	$ 551
Amortization of actuarial (gain) loss	(367)	(308)
Prior Service credit	(6)	(6)
Total recognized in other comprehensive income (loss)	(1,460)	237
Non-U.S. Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain)	519	6,001
Amortization of actuarial (gain) loss	(504)	(193)
Prior Service credit	0	0
Total recognized in other comprehensive income (loss)	$ 15	$ 5,808