Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Income Taxes [Abstract]
Charitable contribution		$ 62,000
Bad debt	68,000tgc_DeferredTaxAssetsBadDebts	68,000tgc_DeferredTaxAssetsBadDebts
Total deferred tax assets - current	68,000	130,000
Net operating loss carryforwards	7,173,000	7,723,000
Oil and gas properties	(894,000)	979,000
Property, Plant and Equipment	711,000	(1,562,000)
Asset retirement obligation	786,000	565,000
Tax credits	202,000	196,000
Miscellaneous	95,000us-gaap_DeferredTaxAssetsOther	98,000us-gaap_DeferredTaxAssetsOther
Valuation allowance	(790,000)	(790,000)
Total deferred tax assets - noncurrent	7,283,000	7,209,000
Net deferred tax asset	$ 7,351,000us-gaap_DeferredTaxAssetsLiabilitiesNet	$ 7,339,000us-gaap_DeferredTaxAssetsLiabilitiesNet

Deferred Tax Assets, Bad Debts

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible charitable contribution carryforwards.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences expected to be realized or consumed within one year or operating cycle, if longer.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from property, plant, and equipment.

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The tax effect as of the balance sheet date of the amount of future tax deductions arising from all unused tax credit carryforwards which have been reduced by a valuation allowance.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from asset retirement obligations. An asset retirement obligation is a legal obligation associated with the disposal or retirement from service of a tangible long-lived asset.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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