Unaudited Supplemental Oil and Gas Information - Schedule of Standardized Measure of Future Net Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Oil and Gas Exploration and Production Industries Disclosures [Abstract]
Standardized measure, beginning of year	$ 9,253	$ 6,747
Sales of oil and natural gas, net of production costs	(3,235)	(3,143)
Net changes in prices and production costs	3,419	2,347
Changes in estimated future development costs
Extensions and discoveries	1,912	511
Sale of minerals in place		(1,049)
Revisions in previous quantity estimates	761	3,416
Previously estimated development costs incurred
Net changes in income taxes	(1,425)
Accretion of discount	925	675
Changes in timing and other	(11)	(251)
Standardized measure, end of year	$ 11,599	$ 9,253

Amount of increase (decrease) in standardized measure of discounted future net cash flow as a result of extensions, discoveries and improved recovery of proved oil and gas reserves.

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Amount of increase (decrease) in standardized measure of discounted future net cash flow as a result of change in estimated future development costs.

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Amount of increase (decrease) in standardized measure of discounted future net cash flow as a result of change in the estimated future income tax on future pretax net cash flows related to the entity's proved oil and gas reserves.

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Amount of increase in standardized measure of discounted future net cash flow as a result of purchases of minerals in place.

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Amount of increase (decrease) in standardized measure of discounted future net cash flow as a result of change in sales and transfer prices and in production (lifting) costs related to future production.

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Amount of increase in standardized measure of discounted future net cash flow as a result of previously estimated development costs incurred.

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Amount of increase (decrease) in standardized measure of discounted future net cash flow as a result of revisions of estimated quantity of oil and gas in proved reserves.

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Amount of (increase) decrease in standardized measure of discounted future net cash flow as a result of sales and transfers of oil and gas produced.

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Amount of increase (decrease) in standardized measure of discounted future net cash flow as a result of changes from other sources.

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Amount of accretion of discount for the standardized measure of discounted future net cash flow related to proved oil and gas reserves.

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Amount of discounted future accumulated cash inflow relating to proved oil and gas reserves.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Form 20-F
-Section Item 18
-Subsection Instruction 2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 31
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e62455-109447

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e62424-109447

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-Publisher FASB
-Name Accounting Standards Codification
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
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-URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e62500-109447

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e62479-109447

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