Annual report pursuant to Section 13 and 15(d)

SEGMENT INFORMATION, MAJOR CUSTOMERS AND GEOGRAPHICAL DATA Schedule of Revenue from External Customers and Long-Lived Assets (Details)

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SEGMENT INFORMATION, MAJOR CUSTOMERS AND GEOGRAPHICAL DATA Schedule of Revenue from External Customers and Long-Lived Assets (Details) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]                      
Operating revenues $ 57,531 $ 61,385 $ 57,878 $ 54,527 $ 56,289 $ 65,006 $ 63,351 $ 62,582 $ 231,321 $ 247,228 $ 281,837
Net property and equipment 673,914       821,809       673,914 821,809  
United States                      
Revenues from External Customers and Long-Lived Assets [Line Items]                      
Operating revenues                 152,187 171,121 222,465
Net property and equipment 533,800       578,900       533,800 578,900  
Latin America and the Caribbean                      
Revenues from External Customers and Long-Lived Assets [Line Items]                      
Operating revenues                 68,936 64,007 40,420
Net property and equipment 120,152       147,828       120,152 147,828  
Europe                      
Revenues from External Customers and Long-Lived Assets [Line Items]                      
Operating revenues                 5,029 5,924 10,582
Net property and equipment 6,697       76,575       6,697 76,575  
Asia                      
Revenues from External Customers and Long-Lived Assets [Line Items]                      
Operating revenues                 5,169 6,176 $ 8,370
Net property and equipment $ 13,265       $ 18,506       $ 13,265 $ 18,506