XML 127 R98.htm IDEA: XBRL DOCUMENT
v3.20.4

Capital Stock (Narrative) (Q3) (Details) |  |  |  |  | 9 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Oct. 02, 2020 Item shares | Jul. 01, 2020 Item shares | Jan. 02, 2020 Item shares | Mar. 17, 2017 $ / shares | Sep. 30, 2020 $ / shares shares | Dec. 31, 2019 $ / shares shares | Dec. 31, 2018 $ / shares shares | Mar. 16, 2017 $ / shares
Capital Stock [Line Items] |  |  |  |  |  |  |  |
Common stock, par value |  |  |  | $ 0.001 | $ 0.001 | $ 0.001 | $ 0.001 |
Preferred stock, shares authorized | shares |  |  |  |  | 25,000,000 | 25,000,000 | 25,000,000 |
Rights Plan [Member] |  |  |  |  |  |  |  |
Capital Stock [Line Items] |  |  |  |  |  |  |  |
Number of preferred share purchase right for each outstanding share of its common stock to shareholder |  |  |  | $ 1 |  |  |  |
Common stock, Threshold for exercise of rights percentage |  |  |  | 4.95% |  |  |  |
Date declared |  |  |  |  |  | Mar. 17, 2017 |  |
Date to be paid |  |  |  |  |  | Mar. 27, 2017 |  |
Date of record |  |  |  |  |  | Mar. 16, 2017 |  |
Subsequent Event [Member] |  |  |  |  |  |  |  |
Capital Stock [Line Items] |  |  |  |  |  |  |  |
Number of directors | Item | 3 |  |  |  |  |  |  |
Right [Member] |  |  |  |  |  |  |  |
Capital Stock [Line Items] |  |  |  |  |  |  |  |
Date declared |  |  |  |  | Mar. 17, 2017 |  |  |
Date to be paid |  |  |  |  | Mar. 27, 2017 |  |  |
Date of record |  |  |  |  | Mar. 16, 2017 |  |  |
Right [Member] | Rights Plan [Member] |  |  |  |  |  |  |  |
Capital Stock [Line Items] |  |  |  |  |  |  |  |
Number of preferred share purchase right for each outstanding share of its common stock to shareholder |  |  |  | $ 1 |  |  |  |
Directors, CFO And Interim CEO [Member] |  |  |  |  |  |  |  |
Capital Stock [Line Items] |  |  |  |  |  |  |  |
Common stock, New shares issued | shares |  | 6,511 |  |  |  |  |  |
Number of directors | Item |  | 3 |  |  |  |  |  |
Directors, CFO And Interim CEO [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |
Capital Stock [Line Items] |  |  |  |  |  |  |  |
Common stock, New shares issued | shares | 4,367 |  | 7,436 |  |  |  |  |
Number of directors | Item |  |  | 3 |  |  |  |  |
Series A Preferred Stock [Member] |  |  |  |  |  |  |  |
Capital Stock [Line Items] |  |  |  |  |  |  |  |
Preferred stock, par value |  |  |  |  | $ 0.0001 | $ 0.0001 | $ 0.0001 |
Preferred stock, shares issued | shares |  |  |  |  | 0 | 0 | 0 |
Preferred stock, shares authorized | shares |  |  |  |  | 10,000 | 10,000 | 10,000 |
Dividends conversion ratio |  |  |  |  | 0.001 |  |  |
Exercise price |  |  |  |  |  |  |  | $ 1.10
Series A Preferred Stock [Member] | Rights Plan [Member] |  |  |  |  |  |  |  |
Capital Stock [Line Items] |  |  |  |  |  |  |  |
Common stock, par value |  |  |  | $ 0.001 |  |  |  |
Preferred stock, shares issued | shares |  |  |  |  | 0 |  |  |
Dividends conversion ratio |  |  |  |  |  | 1 |  |
Exercise price |  |  |  |  |  |  |  | $ 1.10

X
- Definition Capital Stock [Line Items] + References No definition available. + Details
Name: | tgc_CapitalStockLineItems
Namespace Prefix: | tgc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Common Stock, Threshold For Exercise Of Rights Percentage + References No definition available. + Details
Name: | tgc_CommonStockThresholdForExerciseOfRightsPercentage
Namespace Prefix: | tgc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Dividends Declared, Preferred Stock, Number Of Preferred Shares Purchase Right For Each Share Of Common Stock + References No definition available. + Details
Name: | tgc_DividendsDeclaredPreferredStockNumberOfPreferredSharesPurchaseRightForEachShareOfCommonStock
Namespace Prefix: | tgc_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Dividends Payable, Rights Agreement, Conversion + References No definition available. + Details
Name: | tgc_DividendsPayableRightsAgreementConversion
Namespace Prefix: | tgc_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Dividends Payable, Rights Agreement, Preferred Stock, Share Price + References No definition available. + Details
Name: | tgc_DividendsPayableRightsAgreementPreferredStockSharePrice
Namespace Prefix: | tgc_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number Of Directors + References No definition available. + Details
Name: | tgc_NumberOfDirectors
Namespace Prefix: | tgc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face amount or stated value per share of common stock. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Date the declared dividend will be paid, in CCYY-MM-DD format. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4304-108586 + Details
Name: | us-gaap_DividendPayableDateToBePaidDayMonthAndYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Date the dividend to be paid was declared, in CCYY-MM-DD format. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4304-108586 + Details
Name: | us-gaap_DividendsPayableDateDeclaredDayMonthAndYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format. + References No definition available. + Details
Name: | us-gaap_DividendsPayableDateOfRecordDayMonthAndYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_PreferredStockParOrStatedValuePerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_PreferredStockSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_PreferredStockSharesIssued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of new stock issued during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_PlanNameAxis=tgc_RightsPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_RightsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_TitleOfIndividualAxis=tgc_DirectorsChiefFinancialOfficerAndInterimChiefExecutiveOfficerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_SeriesAPreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |