Note 7 - Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Drilling Fluids [Member]
Raw materials:
Raw materials	$ 138,729	$ 152,076
Mats [Member]
Raw materials:
Raw materials	863	1,531
Finished goods - mats	5,447	1,978
Blended Drilling Fluids Components [Member]
Raw materials:
Blended drilling fluids components	31,789	40,971
Raw materials	139,592	153,607
Total	$ 176,828	$ 196,556