XML 121 R74.htm IDEA: XBRL DOCUMENT v3.8.0.1
Property, Plant and Equipment - Additional Information (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Disclosure of detailed information about property, plant and equipment [abstract]    
Capitalized interest $ 36,750 $ 31,680
Write-down of assets 46,697 $ 4,529
Equipment sold or written down to its estimated recoverable amounts 29,800  
Cost incurred for write-down of previously impaired assets $ 16,700