Annual report pursuant to Section 13 and 15(d)

Equity Method Investments - Schedule of Summarized Financial Information (Details)

v3.8.0.1
Equity Method Investments - Schedule of Summarized Financial Information (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2017
Dec. 31, 2017
Dec. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]      
Current assets $ 35,859 $ 35,859 $ 30,837
Non-current assets 21,009 21,009 21,822
Current liabilities 15,151 15,151 20,455
Non-current liabilities 1,056 1,056 1,307
Revenue   133,419 64,637
Operating expenses   111,458 51,240
Net income   21,961 13,397
Schedule of Equity Method Investments [Line Items]      
Equity method investments carrying value 137,299 137,299 156,527
Wireless Maritime Services      
Schedule of Equity Method Investments [Line Items]      
Equity method investments carrying value 137,299 $ 137,299 $ 156,527
Impairment loss $ 16,700