Note 4 - Property, Plant and Equipment (Details Textual) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Manufacturing Facility [Member]
Payments to Acquire Property, Plant, and Equipment		$ 13,000
Manufacturing Facility Including a New Research and Development Center [Member]
Payments to Acquire Property, Plant, and Equipment		46,000
Facility in Conroe Texas [Member]
Payments to Acquire Property, Plant, and Equipment		20,000
Facility in Fourchon Louisiana [Member] | Scenario, Plan [Member]
Payments to Acquire Property, Plant, and Equipment		30,000
Conroe and Fourchon Projects [Member] | Fluids Systems [Member]
Payments to Acquire Property, Plant, and Equipment		26,000
Fluids Systems [Member]
Tangible Asset Impairment Charges	$ 2,600	2,600
Depreciation		39,300	$ 33,200	$ 29,400
Payments to Acquire Property, Plant, and Equipment		$ 69,404	$ 106,973	$ 67,929