Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
U.S. Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Net (gain) loss	$ 3,814	$ 2,068	$ (3,203)
Amortization of net gain (loss)	(552)	(544)	(834)
Total recognized in other (loss) comprehensive income	3,262	1,524	(4,037)
Non-U.S. Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Net (gain) loss	261	225	813
Amortization of net gain (loss)	78	248	(529)
Adjustments		1,849
Foreign currency		31
Total recognized in other (loss) comprehensive income	$ 339	$ 2,353	$ 284