Pensions - Amounts Recognized in Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Domestic Plan [Member] | Accrued Liabilities [Member]
Amounts recognized in the balance sheet:
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	$ (2,098)	$ (2,047)
Domestic Plan [Member] | Pension Benefits Long Term [Member]
Amounts recognized in the balance sheet:
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(32,726)	(31,830)
Foreign Plan [Member] | Accrued Liabilities [Member]
Amounts recognized in the balance sheet:
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(634)	(548)
Foreign Plan [Member] | Pension Benefits Long Term [Member]
Amounts recognized in the balance sheet:
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(23,608)	(17,803)
Pension Plan [Member] | Domestic Plan [Member] | Accrued Liabilities [Member]
Amounts recognized in the balance sheet:
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(1,011)	(1,030)
Pension Plan [Member] | Domestic Plan [Member] | Pension Benefits Long Term [Member]
Amounts recognized in the balance sheet:
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(38,920)	(48,933)
Pension Plan [Member] | Domestic Plan [Member] | Other assets [Member]
Amounts recognized in the balance sheet:
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	0	0
Pension Plan [Member] | Foreign Plan [Member] | Accrued Liabilities [Member]
Amounts recognized in the balance sheet:
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(4,295)	(3,947)
Pension Plan [Member] | Foreign Plan [Member] | Pension Benefits Long Term [Member]
Amounts recognized in the balance sheet:
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(141,253)	(124,017)
Pension Plan [Member] | Foreign Plan [Member] | Other assets [Member]
Amounts recognized in the balance sheet:
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	$ 405	$ 0