Pension and Other Postretirement Benefits - Summary of Amounts Recognized in the Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Employee benefit obligations:
Employee benefit obligations	$ (79,750)	$ (91,947)
Defined Benefit Pension Plan [Member] | U.S. Defined Benefit Pension Plans [Member] | U.S. [Member]
Employee benefit obligations:
Accrued payrolls and employee benefits	(432)	(409)
Employee benefit obligations	(55,406)	(55,309)
Employee benefit obligations current and non current	(55,838)	(55,718)
Defined Benefit Pension Plan [Member] | Foreign Pension Benefits [Member]
Employee benefit obligations:
Accrued payrolls and employee benefits	0	0
Employee benefit obligations	(8,194)	(18,855)
Employee benefit obligations current and non current	(8,194)	(18,855)
Other Postretirement Benefit Plans [Member]
Employee benefit obligations:
Accrued payrolls and employee benefits	(1,371)	(1,276)
Employee benefit obligations	(15,608)	(17,783)
Employee benefit obligations current and non current	$ (16,979)	$ (19,059)