Proved Undeveloped Reserve Locations

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- Definition

The revenues derived from sales of oil or gas in each geographic area during the reporting period divided by the number of barrels of oil produced or thousands of cubic feet of gas produced.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Industry Guide

-Number 2

-Paragraph 3

-Subparagraph A

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- Definition

Amount of estimated future cost to be incurred in developing proved oil and gas reserves.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 30

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62424-109447

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 31

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62455-109447

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- Definition

Net quantities of an enterprise's interests in proved developed reserves of either crude oil (including condensate and natural gas liquids), natural gas, synthetic oil and gas, or other nonrenewable natural resource that is intended to be upgraded into synthetic oil and gas as of the beginning and the end of the year. "Net" quantities of reserves include those relating to the enterprise's operating and nonoperating interests in properties. Quantities of reserves relating to royalty interests owned are included in "net" quantities if the necessary information is available to the enterprise. "Net" quantities does not include reserves relating to interests of others in properties owned by the enterprise. The unit of measure for reserve quantities is defined as "barrels" for oil and synthetic oil reserves or "cubic feet" or "cubic meters" for natural gas and synthetic gas reserves.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61797-109447

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 9

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61884-109447

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Supplemental Oil And Gas Information (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 item	Dec. 31, 2013 item	Dec. 31, 2012
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Proved undeveloped reserve locations	27tgc_ProvedUndevelopedReserveLocations	29tgc_ProvedUndevelopedReserveLocations
future development cost	$ (10,014)	$ (11,162)	$ (7,894)
Barrel Of Oil [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Price	88.34	90.11	88.08
MCF Of Gas [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Price			2.76
Proved Undeveloped Reserves [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
future development cost	$ 8,700
One Proved Undeveloped Reserves [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Proved undeveloped reserve locations	1
One Proved Undeveloped Reserves [Member] \| Barrel Of Oil [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Proved developed reserves (volume)	12
Nine Proved Undeveloped Reserves [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Proved undeveloped reserve locations	9
Proved developed reserves (volume)	155
Eight Proved Undeveloped Reserves [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Proved undeveloped reserve locations	8
Proved developed reserves (volume)	111