Accounts Receivable, Net (Table) (Details) - USD ($) $ in Thousands |
Sep. 30, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|---|---|---|
| ACCOUNTS RECEIVABLE,NET [Abstract] | |||||
| Accounts receivable | $ 80,037 | $ 85,266 | |||
| Less: provision for doubtful receivables | (19,706) | (19,437) | $ (18,278) | $ (18,464) | |
| Accounts receivable, net | $ 56,125 | $ 60,331 | $ 65,829 |