Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Inventory [Line Items]
Raw materials:	$ 147,532		$ 124,441
Total inventory	189,109	$ 170,819	165,336
Drilling fluids
Inventory [Line Items]
Raw materials:	146,021		123,022
Mats
Inventory [Line Items]
Raw materials:	1,511		1,419
Finished goods	9,067		10,400
Blended drilling fluids components
Inventory [Line Items]
Finished goods	$ 32,510		30,495
Difference between revenue guidance in effect before and after Topic 606 | ASU 2014-09
Inventory [Line Items]
Total inventory			$ 5,500