Schedule of Net Periodic Pension and Postretirement (income) Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure
Net actuarial (gain) loss	$ (6,624)	$ (3,203)	$ 17,732
United States Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Service cost	2,239	2,302	2,462
Interest cost	13,151	13,630	13,142
Expected return on plan assets	(12,008)	(13,830)	(14,517)
Amortization of prior service cost	70	96	134
Net actuarial (gain) loss	(6,712)	(4,013)	10,596
Total net periodic pension (income) cost	(3,260)	(1,815)	11,817
Prior service cost	(70)	(96)	(134)
Total recognized in other comprehensive income	(70)	(96)	(134)
Total recognized in net periodic pension (income) cost and other comprehensive income	(3,330)	(1,911)	11,683
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Service cost	818	761	1,006
Interest cost	852	1,185	1,444
Expected return on plan assets	(165)	(443)	(781)
Net actuarial (gain) loss	(310)	815	8,415
Curtailment			(634)
Total net periodic pension (income) cost	1,195	2,318	9,450
Total recognized in net periodic pension (income) cost and other comprehensive income	1,195	2,318	9,450
Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Service cost	34	37	48
Interest cost	201	218	237
Amortization of prior service cost	(496)	(607)	(598)
Net actuarial (gain) loss	398	5	(648)
Special termination benefits	591
Total net periodic pension (income) cost	728	(347)	(961)
Prior service cost		(93)
Prior service credit	496	607	598
Total recognized in other comprehensive income	496	514	598
Total recognized in net periodic pension (income) cost and other comprehensive income	$ 1,224	$ 167	$ (363)

Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Prior Service Cost, Before Tax

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Amount recognized in net periodic benefit cost (credit) and other comprehensive (income) loss.

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Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan.

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Amount of gain (loss) recognized in net periodic benefit (cost) credit from event reducing expected years of future service of present employees or eliminating accrual of defined benefits for some or all future services of present employees.

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Amount of increase in benefit obligation for benefits provided to employees payable from defined benefit plan or payable upon retirement.

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