Pension and Other Postretirement Benefits - Schedule of Amounts Recognized in the Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Employee benefit obligations:
Employee benefit obligations	$ (81,216)	$ (49,146)
U.S. Pension Benefits [Member]
Employee benefit obligations:
Accrued payrolls and employee benefits	(73)	(51)
Employee benefit obligations	(48,278)	(17,470)
Employee benefit obligations current and non current	(48,351)	(17,521)
Foreign Pension Benefits [Member]
Employee benefit obligations:
Accrued payrolls and employee benefits	0	0
Employee benefit obligations	(19,990)	(12,294)
Employee benefit obligations current and non current	(19,990)	(12,294)
Other Postretirement Benefits [Member]
Employee benefit obligations:
Accrued payrolls and employee benefits	(791)	(752)
Employee benefit obligations	(12,948)	(19,377)
Employee benefit obligations current and non current	$ (13,739)	$ (20,129)