XML 60 R44.htm IDEA: XBRL DOCUMENT v3.8.0.1
Inventories (Details) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Inventory [Line Items]    
Raw materials: $ 124,441 $ 116,536
Total inventories 165,336 143,612
Drilling fluids [Member[    
Inventory [Line Items]    
Raw materials: 123,022 115,399
Mats [Member[    
Inventory [Line Items]    
Raw materials: 1,419 1,137
Finished goods 10,400 3,314
Blended drilling fluids components [Member[    
Inventory [Line Items]    
Finished goods $ 30,495 $ 23,762