Note 7 - Inventories (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Drilling Fluids [Member]
Raw materials:
Raw materials	$ 150,905	$ 152,076
Mats [Member]
Raw materials:
Raw materials	1,439	1,531
Finished goods - mats	2,123	1,978
Blended Drilling Fluids Components [Member]
Raw materials:
Blended drilling fluids components	33,533	40,971
Raw materials	152,344	153,607
Total	$ 188,000	$ 196,556