Organization And Accounting Policies (Narrative) (Details) $ in Thousands, in Billions |
1 Months Ended | 3 Months Ended | 6 Months Ended | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
|
Mar. 31, 2018
USD ($)
|
Jul. 31, 2016
USD ($)
|
Jun. 30, 2018
USD ($)
|
Jun. 30, 2017
USD ($)
|
Jun. 30, 2018
USD ($)
item
|
Jun. 30, 2017
USD ($)
|
Jun. 30, 2018
XAF (
)
/ $
|
Jun. 30, 2018
USD ($)
/ $
|
Dec. 31, 2017
USD ($)
|
Dec. 31, 2015
XAF (
)
|
|
| Organization And Accounting Policies [Line Items] | ||||||||||
| Exchange rate | / $ | 563.100 | 563.100 | ||||||||
| Recorded allowance | $ 145 | $ 183 | $ 89 | $ 281 | ||||||
| Receivable balance, net | $ 9,607 | $ 3,556 | ||||||||
| Value added tax reimbursement monthly payment | $ 200 | |||||||||
| Number of VAT reimbursement payments | item | 36 | |||||||||
| Transfers between levels | 0 | 0 | $ 0 | 0 | ||||||
| Gains on foreign currency transactions | 200 | 200 | 100 | 300 | ||||||
| Gabon [Member] | ||||||||||
| Organization And Accounting Policies [Line Items] | ||||||||||
| Recorded allowance | $ 100 | $ 200 | $ 100 | $ 300 | ||||||
| Receivable balance, gross | | 21.5 | 16.3 | ||||||||
| Receivable balance, net | | 7.2 | 4.9 | ||||||||
| Value added tax reimbursement monthly payment | $ 300 | $ 300 | ||||||||
| X | ||||||||||
- Definition Number of VAT reimbursement payments agreed. No definition available.
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| X | ||||||||||
- Definition Organization And Accounting Policies [Line Items] No definition available.
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| X | ||||||||||
- Definition Value Added Tax Reimbursement Monthly Payment No definition available.
|
| X | ||||||||||
- Definition Amounts due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer) for goods or services (including trade receivables) that have been delivered or sold in the normal course of business. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of transfer of financial instrument classified as an asset into (out of) level 3 of the fair value hierarchy. No definition available.
|
| X | ||||||||||
- Definition Foreign exchange rate used to translate amounts denominated in functional currency to reporting currency. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of expense related to write-down of receivables to the amount expected to be collected. Includes, but is not limited to, accounts receivable and notes receivable. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The total amount due to the entity within one year of the balance sheet date (or one operating cycle, if longer) from outside sources, including trade accounts receivable, notes and loans receivable, as well as any other types of receivables, net of allowances established for the purpose of reducing such receivables to an amount that approximates their net realizable value. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Details
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