Quarterly report pursuant to Section 13 or 15(d)

INVESTMENT IN AMAK - Additional Information (Details)

v3.19.2
INVESTMENT IN AMAK - Additional Information (Details)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2019
USD ($)
shares
Mar. 31, 2018
shares
Jun. 30, 2019
USD ($)
Jun. 30, 2018
USD ($)
Jun. 29, 2019
Mar. 31, 2019
Dec. 31, 2018
USD ($)
Mar. 30, 2018
Jun. 30, 1986
ر.س / $
Schedule of Equity Method Investments [Line Items]                  
Proceeds from AMAK share repurchase     $ 440 $ 0          
Treasury Stock                  
Schedule of Equity Method Investments [Line Items]                  
Number of stock exchanged (in shares) | shares   65,000              
AMAK                  
Schedule of Equity Method Investments [Line Items]                  
Percentage of ownership 33.30% 33.41% 33.30% 33.41% 33.40% 33.29% 33.40% 33.44%  
Investment in equity method investment $ 37,300   $ 37,300       $ 38,700    
Number of stock exchanged (in shares) | shares   24,489              
Exchange rate | ر.س / $                 3.75
Proceeds from AMAK share repurchase     400            
Amount receivable for unreimbursed travel expenses $ 100   $ 100       $ 100    
Chief Executive Officer | AMAK                  
Schedule of Equity Method Investments [Line Items]                  
Shares of equity transferred to related party (in shares) | shares 100,000                
Parent | AMAK                  
Schedule of Equity Method Investments [Line Items]                  
Percentage of ownership 33.40%   33.40%