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v2.4.1.9

Income Taxes (Narrative) (Details) (USD $) | 12 Months Ended
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Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Income Tax Reconciliation, Permanent Difference | $ 304,000 tgc_IncomeTaxReconciliationPermanentDifference | $ (4,000)tgc_IncomeTaxReconciliationPermanentDifference | $ 49,000 tgc_IncomeTaxReconciliationPermanentDifference
Valuation allowance | 790,000 us-gaap_DeferredTaxAssetsValuationAllowance | 790,000 us-gaap_DeferredTaxAssetsValuationAllowance |
Federal net operating loss carryforwards | 20,200,000 us-gaap_OperatingLossCarryforwards |  |
Operating Loss Carryforwards | 20,200,000 us-gaap_OperatingLossCarryforwards |  |
Estimated Net Operating Losses Exceed Gross Financial Reporting Amount [Member] |  |  |
Federal net operating loss carryforwards | 1,900,000 us-gaap_OperatingLossCarryforwards / dei_LegalEntityAxis = tgc_EstimatedNetOperatingLossesExceedGrossFinancialReportingAmountMember |  |
Operating Loss Carryforwards | $ 1,900,000 us-gaap_OperatingLossCarryforwards / dei_LegalEntityAxis = tgc_EstimatedNetOperatingLossesExceedGrossFinancialReportingAmountMember |  |

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- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319 + Details
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- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319 + Details
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