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Description Of Business And Significant Accounting Policies (Narrative) (Details) (USD $) | 12 Months Ended |
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Dec. 31, 2014 mi | Dec. 31, 2013 | Dec. 31, 2012 | Mar. 01, 2013
Description Of Business And Significant Accounting Policies [Line Items] |  |  |  |
Length of pipeline, miles | 65 tgc_LengthOfPipelineMiles |  |  |
Certificate of Deposit to cover future asset retirement obligations | $ 120,500 us-gaap_CertificatesOfDepositAtCarryingValue |  |  |
Collateral for a bond to appeal a civil penalty |  |  | 386,000 us-gaap_RestrictedCashAndCashEquivalents |
Unevaluated properties | 462,000 tgc_OilAndGasPropertyFullCostMethodUnevaluatedProperties | 736,000 tgc_OilAndGasPropertyFullCostMethodUnevaluatedProperties |  |
Current cost discount | 10.00%tgc_OilAndGasPropertyFullCostMethodNetCurrentCostDiscount |  |  |
Allowance for doubtful accounts | 14,000 us-gaap_AllowanceForDoubtfulAccountsReceivable | 14,000 us-gaap_AllowanceForDoubtfulAccountsReceivable |  |
Reversal of compensation expense | 59,500 tgc_ReversalOfSharebasedCompensation |  |  |
Federal net operating loss carryforwards | 20,200,000 us-gaap_OperatingLossCarryforwards |  |  |
Deferred tax asset | 7,351,000 us-gaap_DeferredTaxAssetsLiabilitiesNet | 7,339,000 us-gaap_DeferredTaxAssetsLiabilitiesNet |  |
Derivatives | 0 us-gaap_PriceRiskDerivativesAtFairValueNet | 0 us-gaap_PriceRiskDerivativesAtFairValueNet |  |
Sale price of Swan Creek and Pipeline assets |  |  |  | $ 1,500,000 tgc_DiscontinuedOperationSalePrice
Kansas |  |  |  |
Description Of Business And Significant Accounting Policies [Line Items] |  |  |  |
Customers | 2 tgc_NumberOfMajorCustomers / us-gaap_StatementGeographicalAxis = stpr_KS |  |  |
Customer A [Member] |  |  |  |
Description Of Business And Significant Accounting Policies [Line Items] |  |  |  |
Customer's percentage of revenue | 79.30%us-gaap_ConcentrationRiskPercentage1 / us-gaap_MajorCustomersAxis = tgc_CustomerMember | 79.80%us-gaap_ConcentrationRiskPercentage1 / us-gaap_MajorCustomersAxis = tgc_CustomerMember | 79.90%us-gaap_ConcentrationRiskPercentage1 / us-gaap_MajorCustomersAxis = tgc_CustomerMember |
Customer B [Member] |  |  |  |
Description Of Business And Significant Accounting Policies [Line Items] |  |  |  |
Customer's percentage of revenue | 16.50%us-gaap_ConcentrationRiskPercentage1 / us-gaap_MajorCustomersAxis = tgc_CustomerBMember | 14.90%us-gaap_ConcentrationRiskPercentage1 / us-gaap_MajorCustomersAxis = tgc_CustomerBMember | 14.30%us-gaap_ConcentrationRiskPercentage1 / us-gaap_MajorCustomersAxis = tgc_CustomerBMember |
Customer C [Member] |  |  |  |
Description Of Business And Significant Accounting Policies [Line Items] |  |  |  |
Customer's percentage of revenue | 3.80%us-gaap_ConcentrationRiskPercentage1 / us-gaap_MajorCustomersAxis = tgc_CustomerCMember | 1.70%us-gaap_ConcentrationRiskPercentage1 / us-gaap_MajorCustomersAxis = tgc_CustomerCMember | 2.20%us-gaap_ConcentrationRiskPercentage1 / us-gaap_MajorCustomersAxis = tgc_CustomerCMember |
Two Customers [Member] |  |  |  |
Description Of Business And Significant Accounting Policies [Line Items] |  |  |  |
Customer's percentage of accounts receivable | 84.50%tgc_AccountsReceivableMajorCustomerPercentage / us-gaap_MajorCustomersAxis = tgc_TwoCustomersMember | 92.60%tgc_AccountsReceivableMajorCustomerPercentage / us-gaap_MajorCustomersAxis = tgc_TwoCustomersMember |  |
Customer D [Member] |  |  |  |
Description Of Business And Significant Accounting Policies [Line Items] |  |  |  |
Customer's percentage of accounts receivable | 67.80%tgc_AccountsReceivableMajorCustomerPercentage / us-gaap_MajorCustomersAxis = tgc_CustomerDMember | 80.70%tgc_AccountsReceivableMajorCustomerPercentage / us-gaap_MajorCustomersAxis = tgc_CustomerDMember |  |
Minimum [Member] |  |  |  |
Description Of Business And Significant Accounting Policies [Line Items] |  |  |  |
Federal net operating loss carryforwards expiration between, years | Dec. 31, 2019 |  |  |
Minimum [Member] | Other Property And Equipment [Member] |  |  |  |
Description Of Business And Significant Accounting Policies [Line Items] |  |  |  |
Estimated useful life | 2 years |  |  |
Maximum [Member] |  |  |  |
Description Of Business And Significant Accounting Policies [Line Items] |  |  |  |
Federal net operating loss carryforwards expiration between, years | Dec. 31, 2031 |  |  |
Maximum [Member] | Other Property And Equipment [Member] |  |  |  |
Description Of Business And Significant Accounting Policies [Line Items] |  |  |  |
Estimated useful life | 7 years |  |  |

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