Annual report pursuant to Section 13 and 15(d)

Note 18 - Major Customers and Segment Information (Details Textual)

v3.19.1
Note 18 - Major Customers and Segment Information (Details Textual)
$ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2018
USD ($)
Sep. 30, 2018
USD ($)
Jun. 30, 2018
USD ($)
Mar. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Sep. 30, 2017
USD ($)
Jun. 30, 2017
USD ($)
Mar. 31, 2017
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Revenue from Contract with Customer, Including Assessed Tax $ 51,721 $ 60,701 $ 70,255 $ 70,932 $ 34,304 $ 42,323 $ 47,813 $ 49,343 $ 253,609 $ 173,783 $ 215,636
Assets, Total 1,102,935       1,008,504       1,102,935 1,008,504  
Equity Method Investments 121,773       92,169       121,773 92,169  
MexMar [Member]                      
Equity Method Investments 53,840       60,980       53,840 60,980  
Other Equity Method Investment [Member]                      
Equity Method Investments 65,800               65,800    
Corporate Segment [Member]                      
Assets, Total $ 153,151       $ 169,346       $ 153,151 $ 169,346 $ 22,427
Customer Concentration Risk [Member] | Sales Revenue, Net [Member]                      
Number of Major Customers                 10 10 10
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Perenco [Member]                      
Revenue from Contract with Customer, Including Assessed Tax                 $ 26,500 $ 26,800 $ 28,400
Concentration Risk, Percentage                 10.30% 15.20% 13.20%
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Ten Largest Customers [Member]                      
Concentration Risk, Percentage                 47.00% 59.00% 58.00%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member] | Non-US [Member]                      
Revenue from Contract with Customer, Including Assessed Tax                 $ (1,300) $ 1,900 $ (4,200)
Concentration Risk, Percentage                 79.00% 87.00% 85.00%