Commitments And Contingencies (Narrative) (Details)	3 Months Ended
Mar. 31, 2017 $ / bbl	Sep. 30, 2015 USD ($)
Incidence Of Non-Compliance [Member]
Loss Contingencies [Line Items]
Maximum potential loss \| $		$ 386,000
Minimum [Member]
Loss Contingencies [Line Items]
Compensation reduction until WTI posting	70
Compensation reimbursement at WTI posting	85

Compensation Reduction Until, Thirty Day Trailing Average Of West Texas Intermediate

No definition available.

Name:	tgc_CompensationReductionUntilThirtyDayTrailingAverageOfWestTexasIntermediate
Namespace Prefix:	tgc_
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	duration

- Definition

Compensation Reimbursement At Thirty Day Trailing Average Of West Texas Intermediate

+ References

No definition available.

+ Details

Name:	tgc_CompensationReimbursementAtThirtyDayTrailingAverageOfWestTexasIntermediate
Namespace Prefix:	tgc_
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The estimated maximum amount of possible loss from the contingency.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349

+ Details

Name:	us-gaap_LossContingencyRangeOfPossibleLossMaximum
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_LitigationCaseAxis=tgc_IncidenceOfNonComplianceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: