Annual report pursuant to Section 13 and 15(d)

SEGMENT INFORMATION, MAJOR CUSTOMERS AND GEOGRAPHICAL DATA Narrative (Details)

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SEGMENT INFORMATION, MAJOR CUSTOMERS AND GEOGRAPHICAL DATA Narrative (Details) - employee
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Brazil      
Revenue, Major Customer [Line Items]      
Number of employees 194    
Sales | Foreign Operations      
Revenue, Major Customer [Line Items]      
Percentage of operating revenues 29.00% 34.00% 31.00%
Sales | Anadarko Petroleum Corporation      
Revenue, Major Customer [Line Items]      
Percentage of operating revenues 31.00% 28.00% 24.00%
Sales | Petroleo Brasileiro S.A.      
Revenue, Major Customer [Line Items]      
Percentage of operating revenues 23.00% 22.00% 20.00%
Sales | U.S. Government      
Revenue, Major Customer [Line Items]      
Percentage of operating revenues 15.00% 16.00% 16.00%
Unionized Employees Concentration Risk | Number of Employees, Total      
Revenue, Major Customer [Line Items]      
Percentage of operating revenues 28.00%