TransAtlantic Petroleum (TAT) 10-K 26 Mar 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Mar. 22, 2019	Jun. 30, 2018
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Trading Symbol	TAT
Entity Registrant Name	TRANSATLANTIC PETROLEUM LTD.
Entity Central Index Key	0001092289
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		52,496,666
Entity Public Float			$ 41.9

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 9,892,000	$ 18,926,000
Accounts receivable, net
Oil and natural gas sales	12,912,000	15,808,000
Joint interest and other	982,000	1,576,000
Related party	878,000	1,023,000
Prepaid and other current assets	8,696,000	3,866,000
Note receivable - related party	5,828,000
Inventory	5,167,000	7,494,000
Total current assets	44,355,000	48,693,000
Oil and natural gas properties (successful efforts method)
Proved	163,006,000	193,647,000
Unproved	15,695,000	24,445,000
Equipment and other property	14,408,000	14,075,000
Property and equipment, gross	193,109,000	232,167,000
Less accumulated depreciation, depletion and amortization	(105,850,000)	(129,183,000)
Property and equipment, net	87,259,000	102,984,000
Other long-term assets:
Other assets	986,000	2,247,000
Note receivable - related party		6,726,000
Total other assets	986,000	8,973,000
Total assets	132,600,000	160,650,000
Current liabilities:
Accounts payable	3,896,000	4,853,000
Accounts payable - related party	2,922,000	3,141,000
Accrued liabilities	13,073,000	10,014,000
Derivative liability		2,215,000
Loans payable	22,000,000	15,625,000
Total current liabilities	41,891,000	35,848,000
Long-term liabilities:
Asset retirement obligations	4,667,000	4,727,000
Accrued liabilities	7,259,000	8,810,000
Deferred income taxes	20,314,000	19,611,000
Loans payable	0	13,000,000
Total long-term liabilities	32,240,000	46,148,000
Total liabilities	74,131,000	81,996,000
Commitments and contingencies
Shareholders' equity:
Common shares, $0.10 par value, 200,000,000 shares authorized; 52,413,588 shares and 50,319,156 shares issued and outstanding as of December 31, 2018 and 2017, respectively	5,241,000	5,032,000
Treasury shares	(970,000)	(970,000)
Additional paid-in-capital	577,488,000	575,411,000
Accumulated other comprehensive loss	(142,021,000)	(124,766,000)
Accumulated deficit	(427,319,000)	(422,103,000)
Total shareholders' equity	12,419,000	32,604,000
Total liabilities, Series A preferred shares and shareholders' equity	132,600,000	160,650,000
Series A Preferred Shares [Member]
Long-term liabilities:
Preferred shares, value	21,300,000	21,300,000
Related Party [Member] | Series A Preferred Shares [Member]
Long-term liabilities:
Preferred shares, value	$ 24,750,000	$ 24,750,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Common shares, par value	$ 0.10	$ 0.10
Common shares, authorized	200,000,000	200,000,000
Common shares, issued	52,413,588	50,319,156
Common shares, outstanding	52,413,588	50,319,156
Unrelated Party [Member] | Series A Preferred Shares [Member]
Preferred shares, par value	$ 0.01
Preferred shares, authorized	426,000
Preferred shares, issued	426,000
Preferred shares, outstanding	426,000
Preferred shares, liquidation preference per share	$ 50
Related Party [Member] | Series A Preferred Shares [Member]
Preferred shares, par value	$ 0.01
Preferred shares, authorized	495,000
Preferred shares, issued	495,000
Preferred shares, outstanding	495,000
Preferred shares, liquidation preference per share	$ 50

Consolidated Statements of Oper

Consolidated Statements of Operation and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Total revenues	$ 70,789	$ 56,639
Costs and expenses:
Production	10,769	12,249
Exploration, abandonment and impairment	401	934
Seismic and other exploration	489	4,723
General and administrative	14,719	12,817
Depreciation, depletion and amortization	14,059	16,925
Accretion of asset retirement obligations	174	190
Total costs and expenses	45,276	48,406
Operating income	25,513	8,233
Other (expense) income:
Loss on sale of TBNG		(15,226)
Interest and other expense	(10,048)	(8,838)
Interest and other income	1,082	1,098
Loss on commodity derivative contracts	(1,797)	(1,852)
Foreign exchange loss	(10,292)	(1,861)
Total other expense	(21,055)	(26,679)
Income (loss) before income taxes	4,458	(18,446)
Current income tax expense	(2,820)	(2,073)
Deferred income tax expense	(6,854)	(3,356)
Net loss	(5,216)	(23,875)
Other comprehensive loss:
Foreign currency translation adjustment	(17,255)	15,550
Comprehensive loss	$ (22,471)	$ (8,325)
Net loss per common share:
Basic net loss per common share	$ (0.10)	$ (0.50)
Weighted average common shares outstanding	50,505	48,196
Diluted net loss per common share	$ (0.10)	$ (0.50)
Weighted average common and common equivalent shares outstanding	50,505	48,196
Oil and Natural Gas Sales [Member]
Revenues:
Total revenues	$ 70,268	$ 55,523
Purchased Natural Gas [Member]
Revenues:
Total revenues		654
Costs and expenses:
Cost of goods and services sold		568
Other [Member]
Revenues:
Total revenues	521	$ 462
Transportation Costs [Member]
Costs and expenses:
Cost of goods and services sold	$ 4,665

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Common Shares [Member]	Treasury Stock [Member]	Warrants [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2016	$ 38,486	$ 4,722	$ (970)		$ 573,278	$ (140,316)	$ (398,228)
Beginning balance, shares at Dec. 31, 2016		47,220,000	333,000	699,000
Issuance of common shares	1,842	$ 259			1,584
Issuance of common shares (in shares)		2,591,000
Issuance of restricted stock units		$ 51			(51)
Issuance of restricted stock units, shares		507,000
Tax withholding on restricted stock units	(92)				(92)
Share-based compensation	693				693
Foreign currency translation adjustment	15,550					15,550
Net loss	(23,875)						(23,875)
Ending balance at Dec. 31, 2017	$ 32,604	$ 5,032	$ (970)		575,412	(124,766)	(422,103)
Ending balance, shares at Dec. 31, 2017	50,319,156	50,319,000	333,000	699,000
Issuance of common shares	$ 1,842	$ 181			1,660
Issuance of common shares (in shares)		1,808,000
Issuance of restricted stock units		$ 28			(28)
Issuance of restricted stock units, shares		286,000
Expiration of warrants				(699,000)
Tax effect of restricted stock units	(11)				(11)
Share-based compensation	455				455
Foreign currency translation adjustment	(17,255)					(17,255)
Net loss	(5,216)						(5,216)
Ending balance at Dec. 31, 2018	$ 12,419	$ 5,241	$ (970)		$ 577,488	$ (142,021)	$ (427,319)
Ending balance, shares at Dec. 31, 2018	52,413,588	52,413,000	333,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018		Dec. 31, 2017
Operating activities:
Net loss		$ (5,216)		$ (23,875)
Adjustments to reconcile net loss to net cash provided by operating activities:
Share-based compensation		455		693
Foreign currency (income) loss		13,299		(440)
Loss on commodity derivative contracts		1,797		1,852
Cash settlement on commodity derivative contracts		(4,012)		32
Amortization on loan financing costs		42		82
Deferred income tax expense		6,854		3,356
Exploration, abandonment and impairment		401		934
Depreciation, depletion and amortization		14,059		16,925
Accretion of asset retirement obligations		174		190
Loss on Sale of TBNG				15,226
Changes in operating assets and liabilities:
Accounts receivable		(1,358)		2,255
Prepaid expenses and other assets		(6,673)		(859)
Accounts payable and accrued liabilities		7,031		(333)
Net cash provided by operating activities		28,695		17,880
Investing activities:
Additions to oil and natural gas properties		(23,517)		(15,478)
Additions to equipment and other properties		(3,015)		(366)
Proceeds from asset sale				17,779
Net cash provided by (used in) investing activities		(26,532)		1,935
Financing activities:
Tax withholding on restricted share units		(11)		(92)
Loan proceeds		10,000		20,375
Loan repayment		(16,625)		(30,475)
Loan repayment - related party				(3,219)
Net cash used in financing activities		(6,636)		(13,411)
Effect of exchange rate on cash flows, cash equivalents and restricted cash		(5,931)		(1,044)
Net increase (decrease) in cash, cash equivalents and restricted cash		(10,404)		5,360
Cash, cash equivalents and restricted cash, beginning of year	[1]	20,431	[2]	15,071
Cash, cash equivalents and restricted cash, end of year	[2]	10,027		20,431	[1]
Supplemental disclosures:
Cash paid for interest		7,917		5,620
Cash paid for taxes		3,239		2,151
Series A Preferred Shares [Member]
Adjustments to reconcile net loss to net cash provided by operating activities:
Interest on Series A Preferred Shares paid in common shares		$ 1,842		$ 1,842
[1]	The balance at January 1, 2017 includes cash and cash equivalents of $10.0 million, restricted cash of $3.5 million in other assets and TBNG cash held for sale of $1.6 million. The balance at January 1, 2018 includes cash and cash equivalents of $18.9 million and restricted cash of $1.5 million in other assets.
[2]	The end of period balance at December 31, 2017 includes cash and cash equivalents of $18.9 million and restricted cash of $1.5 million in other assets. The end of period balance at December 31, 2018 includes cash and cash equivalents of $9.9 million and restricted cash of $0.1 million in other assets.

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017
Cash and cash equivalents	$ 10,000	$ 9,892	$ 18,926
Thrace Basin Natural Gas (Turkiye) Corporation [Member]
Cash held for sale	1,600
Other Assets [Member]
Restricted cash	$ 3,500	$ 100	$ 1,500

General

General	12 Months Ended
	Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
General	1. General Nature of operations TransAtlantic Petroleum Ltd. (together with its subsidiaries, “we,” “us,” “our,” the “Company” or “TransAtlantic”) is an international oil and natural gas company engaged in acquisition, exploration, development and production. We have focused our operations in countries that have established, yet underexplored petroleum systems, have stable governments, are net importers of petroleum, have an existing petroleum transportation infrastructure and provide favorable commodity pricing, royalty rates and tax rates to exploration and production companies. We hold interests in developed and undeveloped oil and natural gas properties in Turkey and Bulgaria. As of March 22, 2019, approximately 48% of our outstanding common shares were beneficially owned by N. Malone Mitchell 3rd, our chief executive officer and chairman of our board of directors. TransAtlantic is a holding company with two operating segments – Turkey and Bulgaria. Its assets consist of its ownership interests in subsidiaries that primarily own assets in Turkey and Bulgaria. Basis of presentation Our consolidated financial statements are expressed in U.S. Dollars and have been prepared by management in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”). All amounts in these notes to the consolidated financial statements are in U.S. Dollars unless otherwise indicated. In preparing financial statements, management makes informed judgments and estimates that affect the reported amounts of assets and liabilities as of the date of the financial statements and affect the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, management reviews estimates, including those related to fair value measurements associated with acquisitions, stock based compensation and financial derivatives, collectability of accounts receivable, the recoverability and impairment of long-lived assets, contingencies and income taxes. Changes in facts and circumstances may result in revised estimates and actual results may differ from these estimates. On February 24, 2017, we closed the sale of our ownership interests in our subsidiary Thrace Basin Natural Gas (Turkiye) Corporation (“TBNG”) for gross proceeds of $20.7 million and net cash proceeds of $16.1 million, which reflect a $0.2 million post-closing purchase price adjustment. Although the sale of TBNG met the threshold to classify its assets and liabilities as held for sale, it did not meet the requirements to classify its operations as discontinued, as the sale was not considered a strategic shift in our operations. As such, TBNG’s results of operations are classified as continuing operations for all periods presented (see Note 17 “Divestitures and discontinued operations”).

Liquidity

Liquidity	12 Months Ended
	Dec. 31, 2018
Liquidity [Abstract]
Liquidity	2. Liquidity During 2018, we repaid the 2016 Term Loan in full in accordance with its terms and entered into the 2018 Term Loan with DenizBank, A.S. (“DenizBank”) for $10.0 million. (see Note 9 “Loans Payable”). As of December 31, 2018, we had no long-term debt, $22.0 million in short-term debt, $9.9 million in cash and a $2.5 million working capital surplus. Based on current forecasted oil prices for 2019 and beyond, we believe that our cash flows from operations and existing cash on hand are sufficient to conduct our planned operations and meet our contractual requirements, including license obligations through March 31, 2020.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Significant accounting policies	3. Significant accounting policies Basis of preparation Our reporting standard for the presentation of our consolidated financial statements is U.S. GAAP. The consolidated financial statements include the accounts of the Company and all majority-owned, controlled subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. Accounts receivable, net We have receivables for sales of oil and natural gas, as well as receivables related to joint interest accounts, which have a contractual maturity of one year or less. An allowance for doubtful accounts has been established based on management’s review of the collectability of the receivables in light of historical experience, the nature and volume of the receivables and other subjective factors. Accounts receivable are charged against the allowance, upon approval by management, when they are deemed uncollectible. Our allowance for doubtful accounts was $0.5 million at December 31, 2018 and 2017. Cash and cash equivalents Cash and cash equivalents include term deposits and investments with original maturities of three months or less at the date of acquisition. We consider all highly liquid debt instruments purchased with an original maturity of three months or less to be cash equivalents. We determine the appropriate classification of our investments in cash and cash equivalents and marketable securities at the time of purchase and reevaluate such designation at each balance sheet date. Derivative instruments Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 815, Derivatives and Hedging Fair value measurements We follow ASC 820, Fair Value Measurements and Disclosures ASC 820 characterizes inputs used in determining fair value according to a hierarchy that prioritizes those inputs based upon the degree to which they are observable. The three levels of the fair value measurement hierarchy are as follows: Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. Level 2: Quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability. Level 3: Measured based on prices or valuation models that required inputs that are both significant to the fair value measurement and less observable for objective sources (i.e., supported by little or no market activity). As required by ASC 820, financial assets and liabilities are classified based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment, which may affect the valuation of the fair value of assets and liabilities and their placement within the fair value hierarchy levels. The determination of the fair values takes into account the market for our financial assets and liabilities, the associated credit risk and other factors as required by ASC 820. We consider active markets as those in which transactions for the assets or liabilities occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Foreign currency remeasurement and translation The functional currency of our subsidiaries in Turkey and Bulgaria is the New Turkish Lira (“TRY”) and the Bulgarian Lev, respectively. We follow ASC 830, Foreign Currency Matters For certain subsidiaries, translation adjustments result from the process of translating the functional currency of subsidiary financial statements into the U.S. Dollar reporting currency. These translation adjustments are reported separately and accumulated in the consolidated balance sheets as a component of accumulated other comprehensive loss. Oil and natural gas properties In accordance with the successful efforts method of accounting for oil and natural gas properties, costs of productive wells, developmental dry holes and productive leases are capitalized into appropriate groups of properties based on geographical and geological similarities. Acquisition costs of proved properties are amortized using the unit-of-production method based on total proved reserves, and exploration well costs and additional development costs are amortized using the unit-of-production method based on proved developed reserves. Proceeds from the sale of properties are credited to property costs, and a gain or loss is recognized when a significant portion of an amortization base is sold or abandoned. Exploration costs, such as exploratory geological and geophysical costs, delay rentals and exploration overhead, are charged to expense as incurred. Exploratory drilling costs, including the cost of stratigraphic test wells, are initially capitalized but charged to exploration expense if and when the well is determined to be non-productive. The determination of an exploratory well’s ability to produce must be made within one year from the completion of drilling activities. The acquisition costs of unproved acreage are initially capitalized and are carried at cost, net of accumulated impairment provisions, until such leases are transferred to proved properties or charged to exploration expense as impairments of unproved properties. Equipment and other property Equipment and other property are stated at cost, and inventory is stated at weighted average cost which does not exceed replacement cost. Depreciation is calculated using the straight-line method over the estimated useful lives (ranging from 3 to 7 years) of the respective assets. The costs of normal maintenance and repairs are charged to expense as incurred. Material expenditures that increase the life of an asset are capitalized and depreciated over the estimated remaining useful life of the asset. The cost of equipment sold, or otherwise disposed of, and the related accumulated depreciation, are removed from the accounts and any gain or loss is reflected in current earnings. Impairment of long-lived assets We follow the provisions of ASC 360, Property, Plant, and Equipment Unproved oil and natural gas properties do not have producing properties and are valued on acquisition by management, with the assistance of an independent expert when necessary. As reserves are proved through the successful completion of exploratory wells, the cost is transferred to proved properties. The cost of the remaining unproved basis is periodically evaluated by management to assess whether the value of a property has diminished. To do this assessment, management considers (i) estimated potential reserves and future net revenues from an independent expert, (ii) our history in exploring the area, (iii) our future drilling plans per our capital drilling program prepared by our reservoir engineers and operations management and (iv) other factors associated with the area. Impairment is taken on the unproved property value if it is determined that the costs are not likely to be recoverable. The valuation is subjective and requires management to make estimates and assumptions which, with the passage of time, may prove to be materially different from actual results. Joint interest activities Certain of our exploration, development and production activities are conducted jointly with other entities and, accordingly, the consolidated financial statements reflect only our proportionate interest in such activities. Asset retirement obligations We recognize a liability for the fair value of all legal obligations associated with the retirement of tangible, long-lived assets and capitalize an equal amount as a cost of the asset. The cost associated with the abandonment obligation is included in the computation of depreciation, depletion and amortization. The liability accretes until we settle the obligation. We use a credit-adjusted risk-free interest rate in our calculation of asset retirement obligations. Revenue recognition As explained below (see Note 4 “New accounting pronouncements”), on January 1, 2018, we adopted FASB Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers The Company recognizes revenue in accordance with FASB, ASC 606, Revenue from Contracts with Customers Our revenue consists of sales under two contracts, one for crude oil and one for natural gas. The crude oil is delivered to the inlet of a processing center and control is passed through a custodian to the customer at that point. We are paid for crude oil at the inlet plus or minus an adjustment for quality. Our natural gas is metered at the inlet of a transportation pipeline and control is passed at that point. We record natural gas sales at the delivery point to the customer, net of any pricing differentials. There is no material inventory remaining at the end of each reporting period. We have previously deducted any transportation costs, processing fees, or adjustments from revenue and recorded the net amount. Under the new revenue guidance, on January 1, 2018, we now record the gross amount of the revenue and records any fees, or deductions as expenses. Our revenue excludes any amounts collected on behalf of third parties. During the years ended December 31, 2018 and 2017, we sold $68.2 million and $54.9 million, respectively, of oil to Türkiye Petrol Rafinerileri A.Ş. (“TUPRAS”), a privately-owned oil refinery in Turkey, which represented approximately 96.4%, and 97.0% of our total revenues, respectively. Share-based compensation We follow ASC 718, Compensation—Stock Compensation Series A Preferred Shares On November 4, 2016, we issued 921,000 shares of 12.0% Series A Convertible Redeemable Preferred Shares (the “Series A Preferred Shares”). Of the 921,000 Series A Preferred Shares, (i) 815,000 shares were issued in exchange for $40.75 million of our 13.0% Senior Convertible Notes due 2017 (the “2017 Notes”) Income taxes We follow the asset and liability method prescribed by ASC 740, Income Taxes As of December 31, 2018 and 2017, we have recorded a $6.7 million and $8.7 million liability, respectively, primarily due to uncertain tax positions related to the unwinding of all of our crude oil hedge collars and three-way contracts, which are included in long-term accrued liabilities on our consolidated balance sheet. We do not believe there will be any material changes in our unrecognized tax positions over the next twelve months. Our policy is that we recognize interest and penalties accrued on any unrecognized tax positions as a component of income tax expense. We are a Bermuda exempted company, and under current Bermuda law, we are not subject to tax on profits, income or dividends, nor is there any capital gains tax applicable to us in Bermuda. Comprehensive income We follow ASC 220, Comprehensive Income Business combinations We follow ASC 805, Business Combinations Consolidation Per share information Basic per share amounts are calculated using the weighted average common shares outstanding during the year, excluding unvested restricted stock units. We use the treasury stock method to determine the dilutive effect of stock options and other dilutive instruments. Under the treasury stock method, only “in the money” dilutive instruments impact the diluted calculations in computing diluted earnings per share. Diluted calculations reflect the weighted average incremental common shares that would be issued upon exercise of dilutive options assuming the proceeds would be used to repurchase shares at average market prices for the period.

New Accounting Pronouncements

New Accounting Pronouncements	12 Months Ended
	Dec. 31, 2018
Accounting Changes And Error Corrections [Abstract]
New accounting pronouncements	4. New accounting pronouncements In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date. We adopted ASU 2014-09 on January 1, 2018 using the modified retrospective approach. We have a small number of contracts with customers and have identified transactions within the scope of the standard. As a result of adoption of ASU 2014-09, we have determined that it will change our method of recording certain transportation and processing charges that were previously recorded as a reduction of revenues to record such charges as an expense under the new standard. The result of this change was an increase to both revenue and expenses of $4.7 million for the twelve months ended December 31, 2018. The application of the new standard has no impact on our retained earnings and no impact to our net income on an ongoing basis. During the twelve months ended December 31, 2017, this standard would have increased both revenue and expenses by $4.4 million. Contracts for the sale of natural gas and crude oil are evidenced by (1) base contracts for the sale and purchase of natural gas or crude oil, which document the general terms and conditions for the sale, and (2) transaction confirmations, which document the terms of each specific sale. Revenue is measured based on consideration specified in the contract with the customer. We recognize revenue in the amount that reflects the consideration we expect to be entitled to in exchange for transferring control of those goods to the customer. Revenues are recognized for the sale of our net share of production volumes. Sales on behalf of other working interest owners and royalty interest owners are not recognized as revenues. The contract consideration in our contracts are typically allocated to specific performance obligations in the contract according to the price stated in the contract, which usually sets the base oil and natural gas prices based on benchmark prices based on volumes and adjustments for product quality. Payment is generally received one or two months after the sale has occurred. The following table displays the disaggregation of revenue by product type for the twelve months ended December 31, 2018 and 2017: 2018 2017 (in thousands) Oil $ 69,207 $ 58,109 Natural gas 1,061 1,807 Total revenue from customers $ 70,268 $ 59,916 All of our revenues from contracts with customers represent products transferred at the point in time control is transferred to the customer and are generated in Turkey. Transaction price allocated to remaining performance obligations . A significant number of our product sales are short-term in nature with a contract term of one year or less. For those contracts, we have utilized the practical expedient exempting us from disclosure of the transaction price allocated to remaining performance obligations if the performance obligation is part of a contract that has an original expected duration of one year or less. Contract balances . Receivables from contracts with customers are recorded when the right to consideration becomes unconditional, generally when control of the product has been transferred to the customer. Receivables from contracts with customers were $12.9 million and $15.8 million as of December 31, 2018 and December 31, 2017, respectively, and are reported in accounts receivable, net on our consolidated balance sheets. We currently have no assets or liabilities related to our revenue contracts, including no upfront or rights to deficiency payments. Practical expedients . We have made use of certain practical expedients in adopting the new revenue standard, including the value of unsatisfied performance obligations are not disclosed for (i) contracts with an original expected length of one year or less, (ii) contracts for which we recognize revenue at the amount to which we have the right to invoice, (iii) variable consideration which is allocated entirely to a wholly unsatisfied performance obligation and meets the variable allocation criteria in the standard and (iv) only contracts that are not completed at transition. We have not adjusted the promised amount of consideration for the effects of a significant financing component if we expect, at contract inception, that the period between when we transfer a promised good or service to the customer and when the customer pays for that good or service will be one year or less. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash In May 2017, the FASB issued ASU 2017-09, Scope of Modification Accounting Compensation – Stock Compensation In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging (Topic 815) We have reviewed other recently issued, but not yet adopted, accounting standards in order to determine their effects, if any, on our consolidated results of operations, financial position and cash flows. Based on that review, we believe that none of these pronouncements will have a significant effect on current or future earnings or operations.

Series A Preferred Shares

Series A Preferred Shares	12 Months Ended
	Dec. 31, 2018
Temporary Equity Disclosure [Abstract]
Series A preferred shares	5. Series A Preferred Shares Series A Preferred Shares On November 4, 2016, we issued 921,000 Series A Preferred Shares. Of the 921,000 Series A Preferred Shares, (i) 815,000 shares were issued in exchange for $40.75 million of the 2017 Notes, at an exchange rate of 20 Series A Preferred Shares for each $1,000 principal amount of 2017 Notes, and (ii) 106,000 shares were issued and sold for $5.3 million of cash to certain holders of the 2017 Notes. All of the Series A Preferred Shares were issued at a value of $50.00 per share. We used $4.3 million of the gross proceeds to redeem a portion of the remaining 2017 Notes on January 1, 2017. The remaining proceeds were used for general corporate purposes. The Series A Preferred Shares contain a substantive conversion option, are mandatorily redeemable and convert into a fixed number of common shares. As a result, under U.S GAAP, we have classified the Series A Preferred Shares within mezzanine equity in our consolidated balance sheet. As of December 31, 2018, there were $21.3 million of Series A Preferred Shares and $24.8 million of Series A Preferred Shares – related party outstanding (see Note 16 “Related party transactions”). Pursuant to the Certificate of Designations for the Series A Preferred Shares (the “Certificate of Designations”), each Series A Preferred Share may be converted at any time, at the option of the holder, into 45.754 common shares of the Company (which is equal to an initial conversion price of approximately $1.0928 per common share and is subject to customary adjustment for stock splits, stock dividends, recapitalizations or other fundamental changes). If not converted sooner, on November 4, 2024, we are required to redeem the outstanding Series A Preferred Shares in cash at a price per share equal to the liquidation preference plus accrued and unpaid dividends. At any time on or after November 4, 2020, we may redeem all or a portion of the Series A Preferred Shares at the redemption prices listed below (expressed as a percentage of the liquidation preference amount per share) plus accrued and unpaid dividends to the date of redemption, if the closing sale price of the common shares equals or exceeds 150% of the conversion price then in effect for at least 10 trading days (whether or not consecutive) in a period of 20 consecutive trading days, including the last trading day of such 20 trading day period, ending on, and including, the trading day immediately preceding the business day on which we issue a notice of optional redemption. The redemption prices for the 12-month period starting on the date below are: Period Commencing Redemption Price November 4, 2020 105.000% November 4, 2021 103.000% November 4, 2022 101.000% November 4, 2023 and thereafter 100.000% Additionally, upon the occurrence of a change of control, we are required to offer to redeem the Series A Preferred Shares within 120 days after the first date on which such change of control occurred, for cash at a redemption price equal to the liquidation preference per share, plus any accrued and unpaid dividends. Dividends on the Series A Preferred Shares are payable quarterly at our election in cash, common shares or a combination of cash and common shares at an annual dividend rate of 12.0% of the liquidation preference if paid all in cash or 16.0% of the liquidation preference if paid in common shares. If paid partially in cash and partially in common shares, the dividend rate on the cash portion is 12.0%, and the dividend rate on the common share portion is 16.0%. Dividends are payable quarterly, on June 30, September 30, December 31, and March 31 of each year. The holders of the Series A Preferred Shares also are entitled to participate pro-rata in any dividends paid on the common shares on an as-converted-to-common shares basis. As of December 31, 2018 and 2017, we paid $5.3 million and accrued $6.0 million, respectively, in dividends on the Series A Preferred Shares, which is recorded in our consolidated statements of comprehensive loss under the caption “Interest and other expense”. These amounts were paid in cash and common shares. Except as required by Bermuda law the holders of Series A Preferred Shares have no voting rights, except that for so long as at least 400,000 Series A Preferred Shares are outstanding, the holders of the Series A Preferred Shares voting as a separate class have the right to elect two directors to our board of directors. For so long as between 80,000 and 399,999 Series A Preferred Shares are outstanding, the holders of the Series A Preferred Shares voting as a separate class have the right to elect one director to our board of directors. Upon less than 80,000 Series A Preferred Shares remaining outstanding, any directors elected by the holders of Series A Preferred Shares shall immediately resign from our board of directors. The Certificate of Designation also provides that without the approval of the holders of a majority of the outstanding Series A Preferred Shares, we will not issue indebtedness for money borrowed or other securities which are senior to the Series A Preferred Shares in excess of the greater of (i) $100 million or (ii) 35% of our PV-10 of proved reserves as disclosed in our most recent independent reserve report filed or furnished by us on EDGAR.

Property and equipment

Property and equipment	12 Months Ended
	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Property and equipment	6. Property and equipment Oil and natural gas properties The following table sets forth the capitalized costs under the successful efforts method for oil and natural gas properties: 2018 2017 (in thousands) Oil and natural gas properties, proved: Turkey $ 162,494 $ 193,111 Bulgaria 512 536 Total oil and natural gas properties, proved 163,006 193,647 Oil and natural gas properties, unproved: Turkey 14,965 24,445 Bulgaria 730 - Total oil and natural gas properties, unproved 15,695 24,445 Gross oil and natural gas properties 178,701 218,092 Accumulated depletion (100,582 ) (123,225 ) Net oil and natural gas properties $ 78,119 $ 94,867 The decline in oil and natural gas properties during the year ended December 31, 2018 was primarily driven by the devaluation of the Turkish Lira (“TRY”) versus the U.S. Dollar. For the year ended December 31, 2018 and 2017, we have recorded foreign currency translation adjustments which reduced oil and natural gas properties and increased accumulated other comprehensive loss within shareholders’ equity on our consolidated balance sheet. At December 31, 2018 and 2017, we excluded $0.5 million At December 31, 2018, the capitalized costs of our oil and natural gas properties included $6.5 million relating to acquisition costs of proved properties, which are being amortized by the unit-of-production method using total proved reserves, and $53.4 million relating to well costs and additional development costs, which are being amortized by the unit-of-production method using proved developed reserves. At December 31, 2017, the capitalized costs of our oil and natural gas properties included $11.2 million relating to acquisition costs of proved properties, which are being amortized by the unit-of-production method using total proved reserves, and $58.7 million relating to well costs and additional development costs, which are being amortized by the unit-of-production method using proved developed reserves. Impairments of proved properties and impairment of exploratory well costs Proved oil and natural gas properties are reviewed for impairment when events and circumstances indicate the carrying value of such properties may not be recoverable. The factors used to determine fair value include (Level 3 inputs), but are not limited to, estimates of proved reserves, future commodity prices, the timing and amount of future production and capital expenditures and discount rates commensurate with the risk reflective of the lives remaining for the respective oil and natural gas properties. During the year ended December 31, 2018, we recorded $0.3 million of impairment of proved properties and exploratory well costs which are primarily measured using Level 3 inputs primarily relating to two of our gas fields. During the year ended December 31, 2017, we recorded $0.8 million of impairment of proved properties and exploratory well costs which are primarily measured using Level 3 inputs primarily relating to two of our gas fields. Capitalized costs greater than one year As of December 31, 2018, there were no capitalized exploratory well costs greater than one year. As of December 31, 2017, we had $4.0 million of exploratory well costs capitalized for the Pinar-1 well in Turkey. During the first quarter of 2018, the well began producing. Equipment and other property The historical cost of equipment and other property, presented on a gross basis with accumulated depreciation, is summarized as follows: 2018 2017 (in thousands) Other equipment $ 1,240 $ 1,764 Land 149 – Inventory 6,791 4,619 Gas gathering system and facilities 194 135 Vehicles 336 343 Leasehold improvements, office equipment and software 5,698 7,214 Gross equipment and other property 14,408 14,075 Accumulated depreciation (5,268 ) (5,958 ) Net equipment and other property $ 9,140 $ 8,118 At December 31, 2018 and 2017, we classified $5.2 million and $7.5 million of inventory, respectively, as a current asset, which represents our expected inventory consumption during the next twelve months. We classify the remainder of our materials and supply inventory as a long-term asset because such materials will ultimately be classified as a long-term asset when the material is used in the drilling of a well. At December 31, 2018 and 2017, we excluded $12.0 million and $12.1 million of inventory, respectively, from depreciation, as the inventory had not been placed into service.

Derivative instruments

Derivative instruments	12 Months Ended
	Dec. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative instruments	7. Derivative instruments We use derivative instruments to manage certain risks related to commodity prices and foreign currency exchange rates. The use of derivative instruments for risk management is covered by operating policies and is closely monitored by our senior management. We do not hold any derivatives for speculative purposes and do not use derivatives with leveraged or complex features. We have not designated the derivative contracts as hedges for accounting purposes, and accordingly, we record the derivative contracts at fair value and recognize changes in fair value in earnings as they occur. Commodity price derivatives To the extent that a legal right of offset exists, we net the value of our derivative contracts with the same counterparty in our consolidated balance sheets. All of our oil derivative contracts are settled based upon Brent crude oil pricing. We recognize gains and losses related to these contracts on a fair value basis in our consolidated statements of comprehensive loss under the caption “(Loss) gain on derivative contracts.” Settlements of derivative contracts are included in operating activities on our consolidated statements of cash flows under the caption “Cash settlement on derivative contracts.” At December 31, 2018, we had no outstanding commodity derivative contracts with respect to our future crude oil production. At December 31, 2017, we had outstanding commodity derivative contracts with respect to our future crude oil production as set forth in the tables below: Fair Value of Derivative Instruments as of December 31, 2017 Collars Weighted Average Weighted Minimum Average Quantity Price Maximum Price Estimated Fair Type Period (Bbl/day) (per Bbl) (per Bbl) Value of Liability (in thousands) Collar January 1, 2018— February 28, 2018 458 $ 50.00 $ 61.50 $ (178 ) Collar January 1, 2018— March 31, 2018 500 $ 47.00 $ 59.65 (376 ) Collar January 1, 2018— May 31, 2018 298 $ 47.50 $ 61.00 (286 ) Collar January 1, 2018— June 30, 2018 746 $ 47.50 $ 57.10 (1,375 ) Total Estimated Fair Value of Liability $ (2,215 ) Foreign currency derivatives To the extent that a legal right of offset exists, we net the value of our derivative contracts with the same counterparty in our consolidated balance sheets. All of our foreign exchange derivative contracts are settled based upon the contract rate. We recognize gains and losses related to these contracts on a fair value basis in our consolidated statements of comprehensive loss under the caption “(Loss) gain on derivative contracts.” Settlements of derivative contracts are included in operating activities on our consolidated statements of cash flows under the caption “Cash settlement on derivative contracts.” At December 31, 2018 and 2017, we had no outstanding derivative contracts with respect to our foreign exchange rates. During the years ended December 31, 2018 and 2017, we recorded a net loss on derivative contracts of $1.8 million and $1.9 million, respectively. Balance sheet presentation The following table summarizes both: (i) the gross fair value of our commodity derivative instruments by the appropriate balance sheet classification even when the commodity derivative instruments are subject to netting arrangements and qualify for net presentation in our consolidated balance sheets at December 31, 2017, and (ii) the net recorded fair value as reflected on our consolidated balance sheets at December 31, 2017. At December 31, 2018, we did not have any commodity or foreign exchange derivative contracts. As of December 31, 2017 Gross Amount Net Amount of Gross Offset in the Assets Amount of Consolidated Presented in the Recognized Balance Consolidated Underlying Commodity Location on Balance Sheet Assets Sheet Balance Sheet (in thousands) Crude oil Current liabilities $ 2,215 $ – $ 2,215

Asset Retirement obligations

Asset Retirement obligations	12 Months Ended
	Dec. 31, 2018
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement obligations	8. Asset retirement obligations As part of our development of oil and natural gas properties, we incur asset retirement obligations (“ARO”). Our ARO results from our responsibility to abandon and reclaim our net share of all working interest properties and facilities. At December 31, 2018, the net present value of our total ARO was estimated to be $4.7 million, with the undiscounted value being $8.2 million. Total ARO at December 31, 2018 shown in the table below consists of amounts for future plugging and abandonment liabilities on our wellbores and facilities based on third-party estimates of such costs, adjusted for inflation at a rate of approximately 12.65% per annum for Turkey. These values are discounted to present value using our credit-adjusted risk-free rate of 7.55% per annum for Turkey for the year ended December 31, 2018. The following table summarizes the changes in our ARO for the years ended December 31, 2018 and 2017: 2018 2017 (in thousands) Asset retirement obligations at beginning of period $ 4,727 $ 4,833 Liabilities settled – (37 ) Foreign exchange change effect (1,270 ) (259 ) Additions 1,036 – Accretion expense 174 190 Asset retirement obligations at end of period 4,667 4,727 Long-term portion $ 4,667 $ 4,727 Our ARO is measured using primarily Level 3 inputs. The significant unobservable inputs to this fair value measurement include estimates of plugging costs, remediation costs, inflation rate and well life. The inputs are calculated based on historical data as well as current estimated costs.

Loans payable

Loans payable	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Loans payable	9. Loans payable As of the dates indicated, our third-party debt consisted of the following: December 31, December 31, 2018 2017 Fixed and floating rate loans (in thousands) Term Loan (1) $ 22,000 $ 28,625 Loans payable 22,000 28,625 Less: current portion 22,000 15,625 Long-term portion $ – $ 13,000 _______________________________________________________________________________________________________________ (1) Includes 2018, 2017 and 2016 Term Loans. 2016 Term Loan On August 31, 2016, DenizBank entered into a $30.0 million term loan (the “2016 Term Loan”) with TransAtlantic Exploration Mediterranean International Pty Ltd (“TEMI”) under our general credit agreement with DenizBank (the “Credit Agreement”). In addition, we and DenizBank entered into additional agreements with respect to up to $20.0 million of non-cash facilities, including guarantee letters and treasury instruments for future hedging transactions. The 2016 Term Loan bore interest at a fixed rate of 5.25% (plus 0.2625% for Banking and Insurance Transactions Tax per the Turkish government) per annum and was payable in six monthly installments of $1.25 million each through February 2017 and thereafter in twelve monthly installments of $1.88 million each through February 2018. On April 27, 2017, TEMI and DenizBank approved a revised amortization schedule for the 2016 Term Loan. Pursuant to the revised amortization schedule, the maturity date of the 2016 Term Loan was extended from February 2018 to June 2018, and the monthly principal payments were reduced from $1.88 million to $1.38 million. The other terms of the 2016 Term Loan remained unchanged. Amounts repaid under the 2016 Term Loan could not be re-borrowed and early repayments under the 2016 Term Loan were subject to early repayment fees. The 2016 Term Loan was guaranteed by DMLP, Ltd. (“DMLP”), TransAtlantic Turkey, Ltd. (“TransAtlantic Turkey”), Talon Exploration, Ltd. (“Talon Exploration”), and TransAtlantic Worldwide, Ltd. (“TransAtlantic Worldwide”). The 2016 Term Loan contained standard prohibitions on the activities of TEMI as the borrower, including prohibitions on granting of liens on its assets, incurring additional debt, dissolving, liquidating, merging, consolidating, paying dividends, making certain investments, selling assets or transferring revenue, and other similar matters. In addition, the 2016 Term Loan prohibited Amity Oil International Pty Ltd (“Amity”) and Petrogas Petrol Gaz ve Petrokimya Urunleri Insaat Sanayi ve Ticaret A.S. (“Petrogas”) from incurring additional debt. An event of default under the 2016 Term Loan included, among other events, failure to pay principal or interest when due, breach of certain covenants, representations, warranties and obligations, bankruptcy or insolvency and the occurrence of a material adverse effect. The 2016 Term Loan was secured by a pledge of (i) the stock of TEMI, DMLP, TransAtlantic Turkey, and Talon Exploration, (ii) substantially all of the assets of TEMI, (iii) certain real estate owned by Petrogas, (iv) the Gundem real estate and Muratli real estate owned by Gundem Turizm Yatirim ve Isletmeleri A.S. (“Gundem”) and (v) certain Diyarbakir real estate owned 80% by Mr. Mitchell and 20% by Mr. Uras. In addition, TEMI assigned its Turkish collection accounts and its receivables from the sale of oil to DenizBank as additional security for the 2016 Term Loan. Gundem is beneficially owned by Mr. Mitchell, his adult children, and Mr. Uras. Mr. Mitchell is our chief executive officer and chairman of our board of directors. Mr. Uras is our vice president, Turkey. On June 28, 2018, we repaid the 2016 Term Loan in full in accordance with its terms. 2017 Term Loan On November 17, 2017, DenizBank entered into a $20.4 million term loan (the “2017 Term Loan”) with TEMI under the Credit Agreement. The 2017 Term Loan bears interest at a fixed rate of 6.0% (plus 0.3% for Banking and Insurance Transactions Tax per the Turkish government) per annum. The 2017 Term Loan had a grace period which bore no interest or payments due until July 2018. Thereafter, the 2017 Term Loan is payable in one monthly installment of $1.38 million, nine monthly installments of $1.2 million each through April 2019 and thereafter in eight monthly installments of $1.0 million each through December 2019, with the exception of one monthly installment of $1.2 million occurring in October 2019. The 2017 Term Loan matures in December 2019. Amounts repaid under the 2017 Term Loan may not be re-borrowed, and early repayments under the 2017 Term Loan are subject to early repayment fees. The 2017 Term Loan is guaranteed by Petrogas, Amity, Talon Exploration, DMLP, and TransAtlantic Turkey. The 2017 Term Loan contains standard prohibitions on the activities of TEMI as the borrower, including prohibitions on granting of liens on its assets, incurring additional debt, dissolving, liquidating, merging, consolidating, paying dividends, making certain investments, selling assets or transferring revenue, and other similar matters. In addition, the 2017 Term Loan prohibits Amity and Petrogas from incurring additional debt. An event of default under the 2017 Term Loan includes, among other events, failure to pay principal or interest when due, breach of certain covenants, representations, warranties and obligations, bankruptcy or insolvency and the occurrence of a material adverse effect. The 2017 Term Loan is secured by a pledge of (i) the stock of TEMI, DMLP, TransAtlantic Turkey, and Talon Exploration, (ii) substantially all of the assets of TEMI, (iii) certain real estate owned by Petrogas, (iv) the Gundem real estate and Muratli real estate owned by Gundem, (v) certain Diyarbakir real estate owned 80% by Mr. Mitchell and 20% Mr. Uras, and (vi) certain Ankara real estate owned 100% by Mr. Uras. In addition, TEMI assigned its Turkish collection accounts and its receivables from the sale of oil to DenizBank as additional security for the 2017 Term Loan. Gundem is beneficially owned by Mr. Mitchell, his adult children, and Mr. Uras. Mr. Mitchell is our chief executive officer and chairman of our board of directors. Mr. Uras is our vice president, Turkey. At December 31, 2018, we had $13.0 million outstanding under the 2017 Term Loan and no availability, and we were in compliance with the covenants in the 2017 Term Loan. 2018 Term Loan On May 28, 2018, DenizBank entered into a $10.0 million term loan (the “2018 Term Loan”) with TEMI under the Credit Agreement. The 2018 Term Loan bears interest at a fixed rate of 7.25% (plus 0.3% for Banking and Insurance Transactions Tax per the Turkish government) per annum. The 2018 Term Loan had a grace period through July 2018 during which no payments were due. Thereafter, accrued interest on the 2018 Term Loan is payable monthly and the principal on the 2018 Term Loan is payable in five monthly installments of $0.2 million each through December 2018, four monthly installments of $0.5 million each through April 2019, four monthly installments of $1.0 million each through August 2019, and four monthly installments of $0.75 million each through December 2019. The 2018 Term Loan matures in December 2019. Amounts repaid under the 2018 Term Loan may not be reborrowed, and early repayments under the 2018 Term Loan are subject to early repayment fees. The 2018 Term Loan is guaranteed by Petrogas, Amity, Talon Exploration, DMLP, and TransAtlantic Turkey. The 2018 Term Loan contains standard prohibitions on the activities of TEMI as the borrower, including prohibitions on encumbering or creating restrictions or limitations on all or a part of its assets, revenues, or properties, giving guaranties or sureties, selling assets or transferring revenues, dissolving, liquidating, merging, or consolidating, incurring additional debt, paying dividends, making certain investments, undergoing a change of control, and other similar matters. In addition, the 2018 Term Loan prohibits Amity, Talon Exploration, DMLP, and TransAtlantic Turkey from incurring additional debt. An event of default under the 2018 Term Loan includes, among other events, failure to pay principal or interest when due, breach of certain covenants, representations, warranties, and obligations, bankruptcy or insolvency, and the occurrence of a material adverse effect. The 2018 Term Loan is secured by a pledge of (i) the stock of TEMI, DMLP, TransAtlantic Turkey, and Talon Exploration, (ii) substantially all of the assets of TEMI, (iii) certain real estate owned by Petrogas, (iv) certain Gundem real estate and Muratli real estate owned by Gundem, (v) certain Diyarbakir real estate owned 80% by Mr. Mitchell and 20% Mr. Uras, and (vi) certain Ankara real estate owned 100% by Mr. Uras. In addition, TEMI assigned its Turkish collection accounts and its receivables from the sale of oil to DenizBank as additional security for the 2018 Term Loan. Gundem is beneficially owned by Mr. Mitchell, his adult children, and Mr. Uras. Mr. Mitchell is our chief executive officer and chairman of our board of directors. Mr. Uras is our vice president, Turkey. At December 31, 2018, we had $9.0 million outstanding under the 2018 Term Loan and no availability, and we were in compliance with the covenants in the 2018 Term Loan. During the years ended December 31, 2018 and 2017, we recorded interest expense related to the 2016, 2017 and 2018 Term Loan of $1.8 million and $0.9 million, respectively. 2017 Notes The 2017 Notes were issued pursuant to an indenture, dated as of February 20, 2015 (the “Indenture”), between us and U.S. Bank National Association, as trustee (the “Trustee”). The 2017 Notes bore interest at an annual rate of 13.0%, payable semi-annually, in arrears, on January 1 and July 1 of each year. The 2017 Notes matured on July 1, 2017, and on July 3, 2017, we paid off and retired all remaining outstanding 2017 Notes. ANBE Note On December 30, 2015, TransAtlantic Petroleum (USA) Corp (“TransAtlantic USA”) entered into a $5.0 million draw down convertible promissory note (the “ANBE Note”) with ANBE Holdings, L.P. (“ANBE”), an entity owned by the adult children of our chairman and chief executive officer, Mr. Mitchell, and controlled by an entity managed by Mr. Mitchell and his wife. The ANBE Note bore interest at a rate of 13.0% per annum. On October 31, 2016, TransAtlantic USA entered into an amendment of the ANBE Note with ANBE (the “ANBE Amendment”). The ANBE Amendment extended the maturity date of the ANBE Note from October 31, 2016 to September 30, 2017, provided for the ANBE Note to be repaid in four quarterly installments of $0.9 million each in December 2016 and March, June and September 2017, and provided for monthly payments of interest. On February 27, 2017, we repaid the ANBE Note in full with proceeds from the sale of TBNG and terminated it. Unsecured lines of credit Our wholly-owned subsidiaries operating in Turkey are party to unsecured, non-interest bearing lines of credit with a Turkish bank. At December 31, 2018, we had no outstanding borrowings under these lines of credit. Loan financing costs We capitalize certain costs in connection with obtaining our borrowings, such as lender’s fees and related attorney’s fees. These costs are amortized on a straight line basis, which approximates the effective interest method over the term of the loan as a component of interest expense. Amortization of loan financing costs totaled approximately $0.1 million during 2018 and 2017.

Shareholders' equity

Shareholders' equity	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Shareholders' equity	10. Shareholders’ equity Share issuances to holders of Series A Preferred Shares On October 2, 2017, we issued an aggregate of 2,591,384 common shares to holders of the Series A Preferred Shares as payment of the September 30, 2017 quarterly dividend on the Series A Preferred Shares. Each common share was issued at a value of $0.7108 per common share, which was equal to the 15-day volume weighted average price through the close of trading of the common shares on the NYSE American exchange on September 13, 2017. On December 31, 2018, we issued an aggregate of 1,808,001 common shares to holders of the Series A Preferred Shares as payment of the December 31, 2018 quarterly dividend on the Series A Preferred Shares. Each common share was issued at a value of $1.0188 per common share, which was equal to the 15-day volume weighted average price through the close of trading of the common shares on the NYSE American exchange on December 14, 2018. Restricted stock units Under our 2009 Long-Term Incentive Plan (the “Incentive Plan”), we awarded restricted stock units (“RSUs”) and other share-based compensation to certain of our directors, officers, employees and consultants. Each RSU is equal in value to one of our common shares on the grant date. Upon vesting, an award recipient is entitled to a number of common shares equal to the number of vested RSUs. The RSU awards can only be settled in common shares. As a result, RSUs are classified as equity. At the grant date, we make an estimate of the forfeitures expected to occur during the vesting period and record compensation cost, net of the estimated forfeitures, over the requisite service period. The current forfeiture rate is estimated to be 12.5%. Under the Incentive Plan, RSUs vest over specified periods of time ranging from immediately to four years. RSUs are deemed full value awards and their value is equal to the market price of our common shares on the grant date. ASC 718 requires that the Incentive Plan be approved in order to establish a grant date. Under ASC 718, the approval date for the Incentive Plan was February 9, 2009, the date our board of directors approved the Incentive Plan. Share-based compensation of approximately $0.5 million and $0.7 million Number of RSUs (in thousands) Weighted Average Grant Date Fair Value Per RSU Unvested RSUs outstanding at December 31, 2017 513 $ 1.38 Granted 311 1.55 Forfeited (7 ) 1.18 Vested (363 ) 1.49 Unvested RSUs outstanding at December 31, 2018 454 $ 1.42 Earnings per share We account for earnings per share in accordance with ASC Subtopic 260-10, Earnings Per Share The following table presents the basic and diluted earnings per common share computations: (in thousands, except per share amounts) 2018 2017 Net loss $ (5,216 ) $ (23,875 ) Basic net loss per common share: Shares: Weighted average common shares outstanding 50,505 48,196 Basic net loss per common share: $ (0.10 ) $ (0.50 ) Diluted net loss per common share: Shares: Weighted average shares outstanding 50,505 48,196 Dilutive effect of: Restricted share units – – 2017 Notes – – Weighted average common and common equivalent shares outstanding 50,505 48,196 Diluted net loss per common share: $ (0.10 ) $ (0.50 ) Warrants On December 31, 2014, April 24, 2015 and August 13, 2015, we issued 233,334, 233,333 and 233,333 common share purchase warrants (“Warrants”), respectively, to the shareholders of Gundem as consideration for the pledge of Turkish real estate in exchange for an extension of the maturity of a credit agreement between us and a Turkish bank. As consideration for the pledge of Turkish real estate, the independent members of our board of directors approved the issuance of the Warrants to be allocated in accordance with each shareholder’s ownership percentage of Gundem. The Warrants were issued pursuant to a warrant agreement, whereby the Warrants were immediately exercisable and entitled the holder to purchase one common share for each Warrant. The Warrants were issued in December 2014, April 2015 and August 2015 at an exercise price of $5.99, $5.65 and $2.99 per share, respectively. The Warrants expired, unexercised, pursuant to their terms on January 6, 2018.

Income taxes

Income taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income taxes	11. Income taxes The income tax provision differs from the amount that would be obtained by applying the Bermuda statutory income tax rate of 0% for 2018 and 2017 to income (loss) from operations as follows: 2018 2017 (in thousands except rates) Statutory rate 0.00 % 0.00 % Income (loss) before income taxes $ 4,458 $ (18,446 ) Increase (decrease) resulting from: Foreign tax rate differentials $ 4,720 $ 945 Uncertain tax position 935 1,050 Unremitted earnings 2,927 1,677 Change in valuation allowance (4,743 ) 640 Expiration of non-capital tax loss carryovers 4,793 792 Other 1,042 325 Total $ 9,674 $ 5,429 The components of the net deferred income tax liability at December 31, 2018 and 2017 were as follows: 2018 2017 (in thousands) Deferred tax assets Property and equipment $ 609 $ 1,279 Unrealized gains on derivative contracts 432 Timing of accruals 574 132 Non-capital loss carryovers 13,261 16,502 Valuation allowance (13,261 ) (17,731 ) Other – 47 Total deferred tax assets $ 1,183 $ 661 Deferred tax liabilities Property and equipment $ (9,728 ) $ (10,044 ) Unremitted earnings (9,401 ) (9,631 ) Timing of accruals (2,368 ) (597 ) Total deferred tax liabilities (21,497 ) (20,272 ) Net deferred tax liabilities $ (20,314 ) $ (19,611 ) Components of net deferred tax liabilities Non-current assets $ 1,183 $ 661 Non-current liabilities (21,497 ) (20,272 ) Net deferred tax liabilities $ (20,314 ) $ (19,611 ) We have accumulated losses or resource-related deductions available for income tax purposes in Turkey, Romania, Bulgaria and the United States. As of December 31, 2018, we had non-capital tax losses in Turkey of approximately 57.8 million TRY (approximately $11.0 million), which will begin to expire in 2019; non-capital tax losses in Romania of approximately 1.6 million Romanian New Leu (approximately $0.4 million), which will begin to expire in 2019; non-capital losses in Bulgaria of approximately 9.8 million Bulgarian Lev (approximately $5.7 million), which will begin to expire in 2019; and non-capital tax losses in the United States of approximately $53.7 million, which will begin to expire in 2019. As of December 31, 2018 and 2017, we recorded a valuation allowance of $13.3 million and $17.7 million, respectively, as a reduction to our net operating losses and deferred tax assets. Effective October 1, 2009, we continued to the jurisdiction of Bermuda under the Bermuda Companies Act 1981 We file income tax returns in the United States, Turkey, Bulgaria and Cyprus, with Turkey being the only jurisdiction with significant amounts of taxes due. Except for the outstanding examination of the 2011 income tax filings for Petrogas, Turkish income tax filings before 2012 are no longer subject to examination. As the result of 2016 Turkish legislation allowing us the option to enter into an agreement to exempt corporate income tax filings from examination, we were able to close additional years from examination. As of December 31, 2018 and 2017, we recorded a $6.7 million and $8.7 million liability, respectively, primarily due to uncertain tax positions related to the unwinding of all our crude oil hedge collars and three-way contracts, which are included in long-term accrued liabilities on our consolidated balance sheet. The unrecognized tax benefits at December 31, 2018 and 2017 were as follows: 2018 2017 (in thousands) Unrecognized tax benefits at beginning of period $ 8,663 $ 8,079 Gross increases - tax positions in prior period 935 1,125 Foreign exchange change effect (2,884 ) (541 ) Unrecognized tax benefits at end of period $ 6,714 $ 8,663 As of December 31, 2018, there were no material uncertain tax positions for which the total amounts of unrecognized tax benefits will significantly increase or decrease within the next 12 months. Unremitted earnings Our foreign subsidiaries generate earnings that are not subject to Turkish dividend withholding taxes so long as they are permanently reinvested in our operations in Turkey. Pursuant to ASC Topic No. 740-30, undistributed earnings of foreign subsidiaries that are no longer permanently reinvested would become subject to Turkish dividend withholding taxes. Prior to fiscal year 2015, we asserted that the undistributed earnings of our foreign Turkish subsidiaries were permanently reinvested. Primarily due to the increase in our U.S. debt service obligations resulting from the issuance of the 2017 Notes in the aggregate principal amount of $55.0 million in 2015 (see Note 9 “Loans payable”), management concluded that the ability to access certain amounts of foreign earnings would provide greater flexibility to meet corporate cash flow needs without constraining foreign objectives. Accordingly, in the fourth quarter of fiscal year 2015, we withdrew the permanent reinvestment assertion on 135.2 million TRY of cumulative earnings generated by certain of our Turkish foreign subsidiaries through fiscal year 2015. We provided for Turkish dividend withholding taxes on the 135.2 million TRY of cumulative undistributed foreign Turkish earnings, resulting in the recognition of a deferred tax liability. Although the 2017 Notes were retired on July 3, 2017 (see Note 9 “Loans Payable”), due to our obligation to pay dividends on our Series A Preferred Shares issued on November 4, 2016 (see Note 5 “Series A Preferred Shares”), as of December 31, 2018 and 2017, we maintain the same position, and we provided for Turkish dividend, withholding taxes on 329.7 million and 242.1 million TRY, respectively, of cumulative undistributed foreign Turkish earnings, resulting in an additional increase in our deferred tax liability. There is no certainty as to the timing of when or if such Turkish foreign earnings will be distributed in whole or in part.

Segment information

Segment information	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Segment information	12. Segment information In accordance with ASC 280, Segment Reporting Corporate Turkey Bulgaria Total (in thousands) For the year ended December 31, 2018 Total revenues $ – $ 70,789 $ – $ 70,789 Production – 10,649 120 10,769 Transportation costs – 4,665 – 4,665 Exploration, abandonment, and impairment – 401 – 401 Seismic and other exploration – 488 1 489 General and administrative 9,222 5,344 153 14,719 Depreciation, depletion and amortization 142 13,917 – 14,059 Accretion of asset retirement obligations – 151 23 174 Total costs and expenses 9,364 35,615 297 45,276 Operating (loss) income (9,364 ) 35,174 (297 ) 25,513 Interest and other expense (7,026 ) (3,022 ) – (10,048 ) Interest and other income 184 897 1 1,082 Loss on commodity derivative contracts – (1,797 ) – (1,797 ) Foreign exchange gain (loss) (351 ) (9,932 ) (9 ) (10,292 ) (Loss) income before income taxes (16,557 ) 21,320 (305 ) 4,458 Income tax expense – (9,674 ) – (9,674 ) Net loss $ (16,557 ) $ 11,646 $ (305 ) $ (5,216 ) Total assets at December 31, 2018 $ 8,358 $ 122,325 $ 1,917 $ 132,600 Capital expenditures for the year ended December 31, 2018 $ – $ 23,517 $ – $ 23,517 For the year ended December 31, 2017 Total revenues $ – $ 56,639 $ – $ 56,639 Production 36 12,136 77 12,249 Exploration, abandonment, and impairment – 934 – 934 Cost of purchased natural gas – 568 – 568 Seismic and other exploration – 4,723 – 4,723 General and administrative 6,739 5,729 349 12,817 Depreciation, depletion and amortization 188 16,737 – 16,925 Accretion of asset retirement obligations – 169 21 190 Total costs and expenses 6,963 40,996 447 48,406 Operating (loss) income (6,963 ) 15,643 (447 ) 8,233 Loss on sale of TBNG (15,226 ) – – (15,226 ) Interest and other expense (7,794 ) (1,044 ) – (8,838 ) Interest and other income 250 847 1 1,098 Loss on commodity derivative contracts – (1,852 ) – (1,852 ) Foreign exchange gain (loss) 365 (2,239 ) 13 (1,861 ) (Loss) income before income taxes (29,368 ) 11,355 (433 ) (18,446 ) Income tax expense – (5,429 ) – (5,429 ) Net loss $ (29,368 ) $ 5,926 $ (433 ) $ (23,875 ) Total assets at December 31, 2017 $ 61,167 $ 109,699 $ (10,216 ) $ 160,650 Capital expenditures for the year ended December 31, 2017 $ – $ 15,854 $ – $ 15,854

Financial instruments

Financial instruments	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Financial instruments	13. Financial instruments Foreign currency risk We have underlying foreign currency exchange rate exposure. Our currency exposures primarily relate to transactions denominated in the Bulgarian Lev, European Union Euro, and TRY. We are also subject to foreign currency exposures resulting from translating the functional currency of our subsidiary financial statements into the U.S. Dollar reporting currency. We have not used foreign currency forward contracts to manage exchange rate fluctuations. At December 31, 2018 and 2017, we had 7.8 million TRY and $4.0 million TRY, respectively (approximately $1.5 million and $1.1 million, respectively) in cash and cash equivalents, which exposes us to exchange rate risk based on fluctuations in the value of the TRY. Commodity price risk We are exposed to fluctuations in commodity prices for oil and natural gas. Commodity prices are affected by many factors, including but not limited to, supply and demand. Concentration of credit risk The majority of our receivables are within the oil and natural gas industry, primarily from our industry partners and from government agencies. Included in receivables are amounts due from Turkiye Petrolleri Anonim Ortakligi (“TPAO”), the national oil company of Turkey, Zorlu Dogal Gaz Ithalat Ihracat ve Toptan Ticaret A.S. (“Zorlu”), a privately owned natural gas distributor in Turkey, and TUPRAS, which purchase the majority of our oil and natural gas production. The receivables are not collateralized. To date, we have experienced minimal bad debts and have no allowance for doubtful accounts for TUPRAS. The majority of our cash and cash equivalents are held by three financial institutions in the United States and Turkey. Fair value measurements Cash and cash equivalents, receivables, notes receivable, accounts payable, accrued liabilities and the ANBE Note were each estimated to have a fair value approximating the carrying amount at December 31, 2018 and 2017 due to the short maturity of those instruments. The financial assets and liabilities measured on a recurring basis at December 31, 2017 consisted of our commodity derivative contracts. Fair values for options are based on counterparty market prices. The counterparties use market standard valuation methodologies incorporating market inputs for volatility and risk free interest rates in arriving at a fair value for each option contract. Prices are verified by us using analytical tools. There are no performance obligations related to the collar contracts purchased to hedge our oil production. We utilize models based on a range of observable market inputs, including pricing models, quoted market prices of publicly traded securities with similar duration and yield, time value, yield curve, prepayment spreads, default rates and discounted cash flow and the values for these contracts are disclosed in Level 2 of the fair value hierarchy to determine the fair value of our commodity derivative contracts. We review prices received from our counterparty for unusual fluctuations to ensure that the prices represent a reasonable estimate of fair value. At December 31, 2018, the fair value of the 2018 Term Loan and 2017 Term Loan were estimated using a discounted cash flow analysis based on unobservable Level 3 inputs, including our own credit risk associated with the loans payable. At December 31, 2018, the carrying value approximated the fair value for the 2018 Term Loan and 2017 Term Loan. The following table summarizes the valuation of our financial liabilities as of December 31, 2018: Fair Value Measurement Classification Quoted Prices in Active Markets for Identical Assets or Significant Other Significant Liabilities Observable Inputs Unobservable Inputs (Level 1) (Level 2) (Level 3) Total (in thousands) Liabilities: 2017 Term Loan – – (11,938 ) (11,938 ) 2018 Term Loan – – (8,192 ) (8,192 ) Total $ – $ – $ (20,130 ) $ (20,130 ) The following table summarizes the valuation of our financial liabilities as of December 31, 2017: Fair Value Measurement Classification Quoted Prices in Active Markets for Identical Assets or Significant Other Significant Liabilities Observable Inputs Unobservable Inputs (Level 1) (Level 2) (Level 3) Total (in thousands) Measured on a recurring basis Liabilities: Commodity derivative contracts $ – $ (2,215 ) $ – $ (2,215 ) Disclosed but not carried at fair value Liabilities: 2017 Term Loan – – (16,613 ) (16,613 ) 2016 Term Loan – – (7,866 ) (7,866 ) Total $ – $ (2,215 ) $ (24,479 ) $ (26,694 )

Commitments

Commitments	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments	14. Commitments Our aggregate annual commitments, other than our loans payable, as of December 31, 2018 were as follows: Payments Due By Year Total 2019 2020 2021 2022 2023 Thereafter (in thousands) Series A Preferred Shares dividends (1) $ 37,822 $ 5,526 $ 5,526 $ 5,526 $ 5,526 $ 5,526 $ 10,192 Interest 800 800 - - - - - Leases 3,251 963 710 636 626 316 - Total $ 41,873 $ 7,289 $ 6,236 $ 6,162 $ 6,152 $ 5,842 $ 10,192 (1) Dividends on the Series A Preferred Shares may be paid by us, in our sole discretion, in cash at a rate of 12% per annum or in common shares at a rate of 16% per annum or in a combination of cash and common shares. The amounts in the table assume that we pay all future dividend payments solely in cash. Normal operations purchase arrangements are excluded from the table as they are discretionary or being performed under contracts which are cancelable immediately or with a 30-day notice period. We lease office space in Dallas, Texas, Bulgaria, and Turkey. We also lease apartments in Turkey, as well as operations yards in Turkey. Rent expense for the years ended December 31, 2018 and 2017 was $1.3 million and $1.2 million, respectively.

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Contingencies	15. Contingencies Contingencies relating to production leases and exploration permits Selmo We are involved in litigation with persons who claim ownership of a portion of the surface at the Selmo oil field in Turkey. These cases are being vigorously defended by TEMI and Turkish governmental authorities. We do not have enough information to estimate the potential additional operating costs we would incur in the event the purported surface owners’ claims are ultimately successful. Any adjustment arising out of the claims will be recorded when it becomes probable and measurable. Morocco During 2012, we were notified that the Moroccan government may seek to recover approximately $5.5 million in contractual obligations under our Tselfat exploration permit work program. In February 2013, the Moroccan government drew down our $1.0 million bank guarantee that was put in place to ensure our performance of the Tselfat exploration permit work program. Although we believe that the bank guarantee satisfies our contractual obligations, we recorded $5.0 million in accrued liabilities relating to our Tselfat exploration permit during 2012 for this contingency. In September 2016, management determined that, because it had received no communication from the Moroccan government since early 2013, the probability of payment of this contingency is remote, and therefore we reversed the $6.0 million in contingent liabilities previously classified as liabilities held for sale. Bulgaria During 2012, we were notified that the Bulgarian government may seek to recover approximately $2.0 million in contractual obligations under our Aglen exploration permit work program. Due to the Bulgarian government’s January 2012 ban on fracture stimulation and related activities, a force majeure event under the terms of the exploration permit was recognized by the Bulgarian government. Although we invoked force majeure, we recorded $2.0 million in general and administrative expense relating to our Aglen exploration permit during 2012 for this contractual obligation. In October 2015, the Bulgarian Minister of Energy filed a suit in the Sofia City Court against Direct Petroleum Bulgaria EOOD (“Direct Bulgaria”), claiming $200,000 in liquidated damages for Direct Bulgaria’s alleged failure to fulfill its obligations under the Aglen exploration permit work program. In May 2018, the Sofia City Court concluded that Direct Bulgaria did not fail to fulfill its obligations under the Aglen exploration permit work program as Direct Bulgaria received a force majeure event recognition as a result of a fracture stimulation ban in 2012, imposed by the Bulgarian Parliament, which force majeure event had not been terminated before the expiry of Direct Bulgaria’s obligations under the Aglen exploration permit work program. Additionally, the Sofia City Court concluded that, even if Direct Bulgaria had failed to fulfill its obligations under the Aglen exploration permit work program, the Bulgarian Minister of Energy failed to file suit within the three-year limitation period. Therefore, the Sofia City Court dismissed all claims of the Bulgarian Minister of Energy and ordered the Bulgarian Minister of Energy to pay Direct Bulgaria’s attorney’s fees and legal costs for court experts. In June 2018, the Bulgarian Minister of Energy filed an appeal in the Sofia Court of Appeal. In November 2018, the Sofia Court of Appeal concluded that the judgement of the Sofia City Court was correct and, therefore, dismissed the Bulgarian Minister of Energy’s appeal. In January 2019, the Bulgarian Minister of Energy filed an appeal in the Supreme Court of Cassation. We continue to vigorously defend this claim. As a result of the judgement of the Sofia Court of Appeal, we are currently evaluating an adjustment to our contingencies relating to production leases and exploration permits.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related party transactions	16. Related party transactions Series A Preferred Shares transactions On November 4, 2016, we issued 921,000 Series A Preferred Shares. Of the 921,000 Series A Preferred Shares, (i) 815,000 shares were issued in exchange for $40.75 million of our 2017 Notes, at an exchange rate of 20 Series A Preferred Shares for each $1,000 principal amount of 2017 Notes (the “Exchange Offer”), and (ii) 106,000 shares were issued and sold for $5.3 million of cash to certain holders of the 2017 Notes (the “Offering”). In the Exchange Offer, Pinon Foundation, a non-profit charitable organization directed by Mr. Mitchell’s spouse exchanged $10.0 million of the 2017 Notes for 200,000 Series A Preferred Shares; Dalea exchanged $2.1 million of the 2017 Notes for 41,000 Series A Preferred Shares; and trusts benefitting Mr. Mitchell’s four adult children each exchanged $2.0 million of the 2017 Notes for 40,000 Series A Preferred Shares. In the Offering, the Pinon Foundation purchased 5,000 Series A Preferred Shares for $250,000; and each of Mr. Mitchell’s four adult children purchased 1,000 Series A Preferred Shares for $50,000. Pinon Foundation subsequently sold its Series A Preferred Shares to Longfellow Energy, LP, an affiliate of Mr. Mitchell. For more information see Note 5 “Series A Preferred Shares”. Equity transactions On December 31, 2014, April 24, 2015 and August 13, 2015, we issued 134,169, 134,168 and 134,168 Warrants, respectively, to Mr. Mitchell and 23,333, 23,333 and 23,333 Warrants, respectively, to each of Mr. Mitchell’s children, as shareholders of Gundem, as consideration for the pledge of Turkish real estate in exchange for an extension of the maturity date of a credit agreement between us and a Turkish bank. As consideration for the pledge of Turkish real estate, the independent members of our board of directors approved the issuance of the Warrants to be allocated in accordance with each shareholder’s ownership percentage of Gundem. The Warrants were issued pursuant to a warrant agreement, whereby the Warrants were immediately exercisable and entitled the holder to purchase one common share for each Warrant. The Warrants issued in December 2014, April 2015 and August 2015 an exercise price of $5.99, $5.65 and $2.99 per share, respectively. The Warrants expired, unexercised, pursuant to their terms on January 6, 2018. On June 30, 2016, we issued an aggregate of 5,773,305 common shares in private placements under the Securities Act. Of the 5,773,305 common shares, (i) 1,974,452 common shares were issued to Dalea On December 5, 2016, Randy Rochman, chief executive officer of West Family Investments, and Jonathon Fite, co-owner of the general partner of KMF Investment Partners, LP, were appointed to our board of directors. Randy Rochman and KMF Investment Partners, LP held, and currently hold, 15,000 and 69,000 Series A Preferred Shares, respectively. On March 31, 2017, these 84,000 shares ($4.2 million in value) were re-classified to related party. On October 2, 2017, we issued an aggregate of 2,591,384 common shares to holders of the Series A Preferred Shares as payment of the September 30, 2017 quarterly dividend on the Series A Preferred Shares (see Note 10 “Shareholder’s Equity”). Of the 2,591,384 common shares, 1,392,768 common shares were issued to Dalea, the trusts of Mr. Mitchell’s four children, Pinon Foundation, a nonprofit entity controlled by Mrs. Mitchell, KMF Investment Partners, LP, and Randy Rochman. On December 31, 2018, we issued an aggregate of 1,808,001 common shares to holders of the Series A Preferred Shares as payment of the December 31, 2018 quarterly dividend on the Series A Preferred Shares (see Note 10 “Shareholder’s Equity”). Of the 1,808,001 common shares, 971,724 common shares were issued to Dalea, the trusts of Mr. Mitchell’s four children, Longfellow Energy, an entity controlled by Mr. Mitchell, KMF Investment Partners, LP, and Randy Rochman. Dalea Amended Note and Pledge Agreement On April 19, 2016, we entered into a note amendment agreement (the “Note Amendment Agreement”) with Mr. Mitchell, and Dalea, pursuant to which Dalea agreed to deliver an amended and restated promissory note (the “Amended Note”) in favor of us, in the principal sum of $7,964,053, which Amended Note would amend and restate that certain promissory note, dated June 13, 2012, made by Dalea in favor of us in the principal amount of $11.5 million (the “Original Note”). The Note Amendment Agreement reduced the principal amount of the Original Note to $8.0 million in exchange for the cancellation of an account payable of approximately $3.5 million (the “Account Payable”) owed by TransAtlantic Albania Ltd. (“TransAtlantic Albania”), our former subsidiary, to Viking International Limited (“Viking International”) Pursuant to the Note Amendment Agreement, on April 19, 2016, we entered into the Amended Note, which amended and restated the Original Note that was issued in connection with our sale of our former subsidiaries, Viking International and Viking Geophysical Services Ltd. (“Viking Geophysical”) Viking Services B.V., the beneficial owner of Viking International, VOS and Viking Geophysical (“Viking Services”) Master Services Agreement, dated March 3, 2016, by and between Production Solutions International Petrol Arama Hizmetleri Anomin Sirketi (“PSI”), an affiliate of Mr. Mitchell, and TEMI (the “PSI MSA”) In addition, pursuant to the Note Amendment Agreement, on April 19, 2016, we entered into a pledge agreement (the “Pledge Agreement”) with Dalea, whereby Dalea pledged the $2.0 million principal amount of the 2017 Notes owned by Dalea (the “Dalea Convertible Notes”), including any future securities for which the Dalea Convertible Notes are converted or exchanged, as security for the performance of Dalea’s obligations under the Amended Note. The Pledge Agreement provides that interest payable to Dalea under the Dalea Convertible Notes (or any future securities for which the Dalea Convertible Notes are converted or exchanged) will be credited first against the outstanding principal balance of the Amended Note and, upon full repayment of the outstanding principal balance of the Amended Note, any accrued and unpaid interest on the Amended Note. The Pledge Agreement contains customary events of default. On November 4, 2016, Dalea exchanged $2.0 million of the 2017 Notes for 40,000 Series A Preferred Shares. On June 30, 2016, we entered into a waiver with Dalea, whereby we waived our right under the Pledge Agreement to receive the interest payment due July 1, 2016 under the Dalea Convertible Notes in connection with the payment of 201,459 common shares to Dalea with respect to the 2017 Note interest payment paid on June 30, 2016. As of December 31, 2018 and 2017, the amount receivable under the Amended Note was $5.8 million and $6.7 million, respectively. On February 28, 2019, we and Dalea entered into an amendment (the “Note Amendment”) to the Amended Note (as amended by the Note Amendment, the “Note”), pursuant to which we and Dalea agreed to extend the maturity date of the Note to February 26, 2021 (unless otherwise accelerated in accordance with the terms of the Note). Pledge fee agreements In connection with the pledge of the Gundem real estate and Muratli real estate to DenizBank as collateral for the 2016 Term Loan, on August 31, 2016, we entered into a pledge fee agreement with Gundem (the “Gundem Fee Agreement”) pursuant to which we pay Gundem a fee equal to 5% per annum of the collateral value of the Gundem real estate and Muratli real estate. Pursuant to the Gundem Fee Agreement, the Gundem real estate has a deemed collateral value of $10.0 million and the Muratli real estate has a deemed collateral value of $5.0 million. In connection with the pledge of certain Diyarbakir real estate to DenizBank as collateral for the 2016 Term Loan, on August 31, 2016, we entered into a pledge fee agreement with Messrs. Mitchell and Uras (the “Diyarbakir Fee Agreement”) pursuant to which we pay Messrs. Mitchell and Uras a fee of 5% per annum of the collateral value of the Diyarbakir real estate. Pursuant to the Diyarbakir Fee Agreement, the Diyarbakir real estate has a deemed collateral value of $5.0 million. Amounts payable to Mr. Mitchell under the Gundem Fee Agreement and the Diyarbakir Fee Agreement will be used to reduce the outstanding principal amount of the Amended Note. During the year ended December 31, 2018 and 2017, we reduced the principal amount of the Amended Note by $0.6 million Service transactions Effective May 1, 2008, we entered into a service agreement, as amended (the “Service Agreement”), with Longfellow Energy, LP (“Longfellow”), Viking Drilling LLC (“Viking Drilling”), MedOil Supply, LLC and Riata Management, LLC (“Riata Management”). Mr. Mitchell and his wife own 100% of Riata Management. In addition, Mr. Mitchell, his wife and his children indirectly own 100% of Longfellow. Riata Management owns 100% of MedOil Supply, LLC. Dalea owns 100% of Viking Drilling. Under the terms of the Service Agreement, we pay, or are paid, for the actual cost of the services rendered plus the actual cost of reasonable expenses on a monthly basis. On June 13, 2012, we entered into separate master services agreements with each of Viking International, Viking Petrol Sahasi Hizmetleri AS (“VOS”) and Viking Geophysical in connection with the sale of our oilfield services business to a joint venture owned by Dalea and funds managed by Abraaj Investment Management Limited. Pursuant to the master services agreements with Viking International and VOS, we are entitled to receive certain oilfield services and materials, including, but not limited to, drilling rigs and fracture stimulation that are needed for our operations in Bulgaria and Turkey. Pursuant to the master services agreement with Viking Geophysical, we are also entitled to receive geophysical services and materials that are needed for our operations in those countries. Each master services agreement is for a five-year term, with automatic one-year extensions absent notice of termination from either party. Currently, we can contract for services and materials on a firm basis and, to the extent that we do not contract for all of their services or materials, Viking International, VOS and Viking Geophysical are allowed to contract with third parties for any remaining capacity. On March 3, 2016, Mr. Mitchell closed a transaction whereby he sold his interest in Viking Services to a third party. As part of the transaction, Mr. Mitchell acquired certain equipment used in the performance of stimulation, wireline, workover and similar services, which equipment is owned and operated by PSI. PSI is beneficially owned by Dalea Investment Group, LLC, which is controlled by Mr. Mitchell. Consequently, on March 3, 2016, TEMI entered into the PSI MSA on substantially similar terms to our prior master services agreements with Viking International, VOS and VGS. Pursuant to the PSI MSA, PSI will perform services on behalf of TEMI and its affiliates. On February 28, 2019, TEMI and PSI entered into an amendment (the “PSI MSA Amendment”) to the PSI MSA, pursuant to which PSI and TEMI agreed to extend the primary term of the PSI MSA to February 26, 2021, with automatic successive renewal terms of one (1) year each, unless terminated by PSI or TEMI by written notice at least sixty (60) days prior to the end of the primary term or any successive renewal term. The master services agreements with each of Viking International, VOS and Viking Geophysical currently remain in effect. On August 7, 2018 and effective as of June 14, 2018, our wholly owned subsidiary, TransAtlantic USA, entered into a sublease agreement (the “Sublease”) with Longfellow to lease corporate office space located at 16803 North Dallas Parkway, Addison, Texas. TransAtlantic USA subleases approximately 10,000 square feet of corporate office space in Addison, Texas. The initial lease term under the Sublease commenced on June 14, 2018 (the “Commencement Date”) and expires on June 30, 2020, unless earlier terminated in accordance with the Sublease. From the Commencement Date until June 30, 2019, TransAtlantic USA is required to pay monthly rent of $18,333.33 to Longfellow, plus utilities, real property taxes, and liability insurance (to the extent that TransAtlantic USA does not obtain its own liability insurance). The monthly rent increases by $416.67 for the period commencing June 30, 2019 and ending June 30, 2021. On March 20, 2017, we entered into a second amendment to the Master Services Agreement among us and Longfellow Energy, LP, a Texas limited partnership, Viking Drilling, LLC, a Nevada limited liability company, RIATA Management, LLC, an Oklahoma limited liability company, Longfellow Nemaha, LLC, a Texas limited liability company, Red Rock Minerals, LP, a Delaware limited partnership, Red Rock Advisors, LLC, a Texas limited liability company, Production Solutions International Limited , a Bermuda exempted company, and Nexlube Operating, LLC, a Delaware limited liability company, and their subsidiaries (collectively, the “Riata Entities”), adding and removing certain of the Riata Entities and expanding the scope of services. For the years ended December 31, 2018 and 2017, we incurred capital and operating expenditures of $10.6 million and $9.3 million, respectively, related to our various related party agreements. ANBE Note On December 30, 2015, TransAtlantic USA entered into the $5.0 million Note with ANBE, an entity owned by the children of our chairman and chief executive officer, Mr. Mitchell and controlled by an entity managed by Mr. Mitchell and his wife. The ANBE Note bears interest at a rate of 13.0% per annum. On December 30, 2015, we borrowed the Initial Advance of $3.6 million for general corporate purposes. On June 30, 2016, we issued 355,826 common shares in a private placement to On October 31, 2016, TransAtlantic USA entered into an amendment of the ANBE Note with ANBE (the “ANBE Amendment”). The ANBE Amendment extended the maturity date of the ANBE Note from October 31, 2016 to September 30, 2017, provided for the ANBE Note to be repaid in four quarterly installments of $0.9 million each in December 2016 and March, June and September 2017, and provided for monthly payments of interest. On February 27, 2017, we repaid the ANBE Note in full and terminated it with proceeds from the sale of TBNG. The following table summarizes related party accounts receivable and accounts payable as of December 31, 2018 and December 31, 2017: 2018 2017 (in thousands) Related party accounts receivable: Riata Management Service Agreement $ 526 $ 576 PSI MSA 352 447 Total related party accounts receivable $ 878 $ 1,023 Related party accounts payable: Riata Management Service Agreement $ 372 $ 341 PSI MSA 2,439 2,119 Board of Directors 111 – Interest payable on Series A Preferred Shares – 681 Total related party accounts payable $ 2,922 $ 3,141

Divestitures and Discontinued O

Divestitures and Discontinued Operations	12 Months Ended
	Dec. 31, 2018
Discontinued Operations And Disposal Groups [Abstract]
Divestitures and discontinued operations	17. Divestitures and discontinued operations TBNG On October 13, 2016, we entered into a share purchase agreement (the “Purchase Agreement”) with Valeura Energy Netherlands B.V. (“Valeura”) for the sale of all of the equity interests in TBNG, our wholly-owned subsidiary. TBNG owned a portion our interests in the Thrace Basin area in Turkey. Although the sale of TBNG met the threshold to classify its assets and liabilities as held for sale, it did not meet the requirements to classify its operations as discontinued as the sale was not considered a strategic shift in our operations. As such, TBNG’s results of operations are classified as continuing operations for all periods presented. On February 24, 2017, we closed on the sale of TBNG for gross proceeds of $20.7 million and net cash proceeds of $16.1 million, effective as of March 31, 2016. The purchase price was subject to post-closing adjustments, and we agreed to escrow $3.1 million of the purchase price for 30 days to satisfy any agreed upon purchase price adjustments. We agreed to a $0.2 million reduction to the purchase price, and on April 10, 2017, we collected $2.9 million of the escrowed funds. For the year ended December 31, 2017, we recorded a non-cash net loss of $15.2 million on the sale of TBNG. The loss related to the reclassification of the TBNG accumulated foreign currency translation adjustment that was realized into earnings from accumulated other comprehensive loss within shareholders’ equity. The calculation of the loss on sale is presented below: Loss on Sale (in thousands) Total cash proceeds for TBNG $ 20,707 Less: TBNG net assets 12,869 Gain on sale before accumulated foreign currency translation adjustment 7,838 Less: TBNG accumulated foreign currency translation adjustment (23,064 ) Net loss on sale of TBNG $ (15,226 ) Discontinued operations in Albania As of December 31, 2015, we classified our Albania segment as assets and liabilities held for sale and presented the operating results within discontinued operations for all periods presented. In February 2016, we sold all of the outstanding equity in our wholly-owned subsidiary, Stream Oil & Gas Ltd. (“Stream”), to GBC Oil Company. On September 1, 2016, we completed a joint venture transaction with respect to the assets in the Delvina gas field in Albania (the “Delvina Assets”). We transferred (the “Transfer”) 75% of the outstanding shares of Delvina Gas Company Ltd. (“DelvinaCo”), which owned the Delvina Assets, to Ionian Gas Company Ltd. (“Ionian”) in exchange for Ionian’s agreement to pay $12.0 million to DelvinaCo, which was to be used primarily to repay debt and for general corporate purposes with respect to the Delvina Assets. After the Transfer, we retained a 25% equity interest in DelvinaCo and agreed to pay 25% of the operating costs of DelvinaCo, subject to a three-year deferral of capital expenditures. On August 9, 2017, due to continued failures by our joint venture partners to timely meet their obligations, uncompleted local governmental ratifications, and our prioritization of funds, we transferred our 25% equity interest in DelvinaCo to Delvina Investment Partners Ltd. in exchange for a release of all claims with respect to DelvinaCo and a cash payment of $300,000 for amounts owed to us under agreements entered into in connection with the DelvinaCo joint venture transaction. Additionally, we terminated all of our responsibilities as operator and our obligations to pay any operating costs or any other expenditures with respect to DelvinaCo. This divestiture completed our departure from all Albanian operations and assets.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	18. Subsequent events 2019 Term Loan On February 22, 2019, TEMI entered into a $20.0 million term loan (the “2019 Term Loan”) with DenizBank under the Credit Agreement. The 2019 Term Loan bears interest at a fixed rate of 7.5% (plus 0.375% for Banking and Insurance Transactions Tax per the Turkish government) per annum. The 2019 Term Loan has a ten-month grace period during which the 2019 Term Loan bears interest but no payments are due other than a single interest only payment of $0.76 million in August 2019. After the ten-month grace period, the 2019 Term Loan is payable in fourteen monthly principal installments of $1.43 million plus interest. The 2019 Term Loan matures in February 2021. Amounts repaid under the 2019 Term Loan may not be re-borrowed, and early repayments under the 2019 Term Loan are subject to early repayment fees. The 2019 Term Loan is guaranteed by Petrogas, Amity, Talon Exploration, DMLP, and TransAtlantic Turkey. The 2019 Term Loan contains standard prohibitions on the activities of TEMI as the borrower, including prohibitions on encumbering or creating restrictions or limitations on all or a part of its assets, revenues, or properties, giving guaranties or sureties, selling assets or transferring revenues, dissolving, liquidating, merging, or consolidating, incurring additional debt, paying dividends, making certain investments, undergoing a change of control, and other similar matters. In addition, the 2019 Term Loan prohibits Amity, Talon Exploration, DMLP, and Transatlantic Turkey from incurring additional debt. An event of default under the 2019 Term Loan includes, among other events, failure to pay principal or interest when due, breach of certain covenants, representations, warranties, and obligations, bankruptcy or insolvency, and the occurrence of a material adverse effect. The 2019 Term Loan is secured by a pledge of (i) the stock of TEMI, DMLP, TransAtlantic Turkey, and Talon Exploration, (ii) substantially all of the assets of TEMI, (iii) certain real estate owned by Petrogas, (iv) certain Gundem real estate and Muratli real estate owned by Gundem, (v) certain Diyarbakir real estate owned 80% by Mr. Mitchell and 20% by Mr. Uras, and (vi) certain Ankara real estate owned 100% by Mr. Uras. In addition, TEMI has assigned its Turkish collection accounts and its receivables from the sale of oil to the Lender as additional security for the 2019 Term Loan. Gundem is beneficially owned by Mr. Mitchell, his adult children, and Mr. Uras. Mr. Mitchell is our Chief Executive Officer and Chairman of the Board. Mr. Uras is our Vice President, Turkey. Note Amendment On February 28, 2019, we and Dalea entered into the Note Amendment to the Amended Note, pursuant to which we and Dalea agreed to extend the maturity date of the Note to February 26, 2021 (unless otherwise accelerated in accordance with the terms of the Note). PSI MSA Amendment On February 28, 2019, TEMI and PSI entered into an amendment (the “PSI MSA Amendment”) to the PSI MSA, pursuant to which PSI and TEMI agreed to extend the primary term of the PSI MSA to February 26, 2021, with automatic successive renewal terms of one year each, unless terminated by PSI or TEMI by written notice at least 60 days prior to the end of the primary term or any successive renewal term.

General (Policies)

General (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Nature of operations	Nature of operations TransAtlantic Petroleum Ltd. (together with its subsidiaries, “we,” “us,” “our,” the “Company” or “TransAtlantic”) is an international oil and natural gas company engaged in acquisition, exploration, development and production. We have focused our operations in countries that have established, yet underexplored petroleum systems, have stable governments, are net importers of petroleum, have an existing petroleum transportation infrastructure and provide favorable commodity pricing, royalty rates and tax rates to exploration and production companies. We hold interests in developed and undeveloped oil and natural gas properties in Turkey and Bulgaria. As of March 22, 2019, approximately 48% of our outstanding common shares were beneficially owned by N. Malone Mitchell 3rd, our chief executive officer and chairman of our board of directors. TransAtlantic is a holding company with two operating segments – Turkey and Bulgaria. Its assets consist of its ownership interests in subsidiaries that primarily own assets in Turkey and Bulgaria.
Basis of presentation	Basis of presentation Our consolidated financial statements are expressed in U.S. Dollars and have been prepared by management in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”). All amounts in these notes to the consolidated financial statements are in U.S. Dollars unless otherwise indicated. In preparing financial statements, management makes informed judgments and estimates that affect the reported amounts of assets and liabilities as of the date of the financial statements and affect the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, management reviews estimates, including those related to fair value measurements associated with acquisitions, stock based compensation and financial derivatives, collectability of accounts receivable, the recoverability and impairment of long-lived assets, contingencies and income taxes. Changes in facts and circumstances may result in revised estimates and actual results may differ from these estimates. On February 24, 2017, we closed the sale of our ownership interests in our subsidiary Thrace Basin Natural Gas (Turkiye) Corporation (“TBNG”) for gross proceeds of $20.7 million and net cash proceeds of $16.1 million, which reflect a $0.2 million post-closing purchase price adjustment. Although the sale of TBNG met the threshold to classify its assets and liabilities as held for sale, it did not meet the requirements to classify its operations as discontinued, as the sale was not considered a strategic shift in our operations. As such, TBNG’s results of operations are classified as continuing operations for all periods presented (see Note 17 “Divestitures and discontinued operations”).
Basis of preparation	Basis of preparation Our reporting standard for the presentation of our consolidated financial statements is U.S. GAAP. The consolidated financial statements include the accounts of the Company and all majority-owned, controlled subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation.
Accounts receivable, net	Accounts receivable, net We have receivables for sales of oil and natural gas, as well as receivables related to joint interest accounts, which have a contractual maturity of one year or less. An allowance for doubtful accounts has been established based on management’s review of the collectability of the receivables in light of historical experience, the nature and volume of the receivables and other subjective factors. Accounts receivable are charged against the allowance, upon approval by management, when they are deemed uncollectible. Our allowance for doubtful accounts was $0.5 million at December 31, 2018 and 2017.
Cash and cash equivalents	Cash and cash equivalents Cash and cash equivalents include term deposits and investments with original maturities of three months or less at the date of acquisition. We consider all highly liquid debt instruments purchased with an original maturity of three months or less to be cash equivalents. We determine the appropriate classification of our investments in cash and cash equivalents and marketable securities at the time of purchase and reevaluate such designation at each balance sheet date.
Derivative instruments	Derivative instruments Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 815, Derivatives and Hedging
Fair value measurements	Fair value measurements We follow ASC 820, Fair Value Measurements and Disclosures ASC 820 characterizes inputs used in determining fair value according to a hierarchy that prioritizes those inputs based upon the degree to which they are observable. The three levels of the fair value measurement hierarchy are as follows: Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. Level 2: Quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability. Level 3: Measured based on prices or valuation models that required inputs that are both significant to the fair value measurement and less observable for objective sources (i.e., supported by little or no market activity). As required by ASC 820, financial assets and liabilities are classified based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment, which may affect the valuation of the fair value of assets and liabilities and their placement within the fair value hierarchy levels. The determination of the fair values takes into account the market for our financial assets and liabilities, the associated credit risk and other factors as required by ASC 820. We consider active markets as those in which transactions for the assets or liabilities occur in sufficient frequency and volume to provide pricing information on an ongoing basis.
Foreign currency remeasurement and translation	Foreign currency remeasurement and translation The functional currency of our subsidiaries in Turkey and Bulgaria is the New Turkish Lira (“TRY”) and the Bulgarian Lev, respectively. We follow ASC 830, Foreign Currency Matters For certain subsidiaries, translation adjustments result from the process of translating the functional currency of subsidiary financial statements into the U.S. Dollar reporting currency. These translation adjustments are reported separately and accumulated in the consolidated balance sheets as a component of accumulated other comprehensive loss.
Oil and natural gas properties	Oil and natural gas properties In accordance with the successful efforts method of accounting for oil and natural gas properties, costs of productive wells, developmental dry holes and productive leases are capitalized into appropriate groups of properties based on geographical and geological similarities. Acquisition costs of proved properties are amortized using the unit-of-production method based on total proved reserves, and exploration well costs and additional development costs are amortized using the unit-of-production method based on proved developed reserves. Proceeds from the sale of properties are credited to property costs, and a gain or loss is recognized when a significant portion of an amortization base is sold or abandoned. Exploration costs, such as exploratory geological and geophysical costs, delay rentals and exploration overhead, are charged to expense as incurred. Exploratory drilling costs, including the cost of stratigraphic test wells, are initially capitalized but charged to exploration expense if and when the well is determined to be non-productive. The determination of an exploratory well’s ability to produce must be made within one year from the completion of drilling activities. The acquisition costs of unproved acreage are initially capitalized and are carried at cost, net of accumulated impairment provisions, until such leases are transferred to proved properties or charged to exploration expense as impairments of unproved properties.
Equipment and other property	Equipment and other property Equipment and other property are stated at cost, and inventory is stated at weighted average cost which does not exceed replacement cost. Depreciation is calculated using the straight-line method over the estimated useful lives (ranging from 3 to 7 years) of the respective assets. The costs of normal maintenance and repairs are charged to expense as incurred. Material expenditures that increase the life of an asset are capitalized and depreciated over the estimated remaining useful life of the asset. The cost of equipment sold, or otherwise disposed of, and the related accumulated depreciation, are removed from the accounts and any gain or loss is reflected in current earnings.
Impairment of long-lived assets	Impairment of long-lived assets We follow the provisions of ASC 360, Property, Plant, and Equipment Unproved oil and natural gas properties do not have producing properties and are valued on acquisition by management, with the assistance of an independent expert when necessary. As reserves are proved through the successful completion of exploratory wells, the cost is transferred to proved properties. The cost of the remaining unproved basis is periodically evaluated by management to assess whether the value of a property has diminished. To do this assessment, management considers (i) estimated potential reserves and future net revenues from an independent expert, (ii) our history in exploring the area, (iii) our future drilling plans per our capital drilling program prepared by our reservoir engineers and operations management and (iv) other factors associated with the area. Impairment is taken on the unproved property value if it is determined that the costs are not likely to be recoverable. The valuation is subjective and requires management to make estimates and assumptions which, with the passage of time, may prove to be materially different from actual results.
Joint interest activities	Joint interest activities Certain of our exploration, development and production activities are conducted jointly with other entities and, accordingly, the consolidated financial statements reflect only our proportionate interest in such activities.
Asset retirement obligations	Asset retirement obligations We recognize a liability for the fair value of all legal obligations associated with the retirement of tangible, long-lived assets and capitalize an equal amount as a cost of the asset. The cost associated with the abandonment obligation is included in the computation of depreciation, depletion and amortization. The liability accretes until we settle the obligation. We use a credit-adjusted risk-free interest rate in our calculation of asset retirement obligations.
Revenue recognition	Revenue recognition As explained below (see Note 4 “New accounting pronouncements”), on January 1, 2018, we adopted FASB Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers The Company recognizes revenue in accordance with FASB, ASC 606, Revenue from Contracts with Customers Our revenue consists of sales under two contracts, one for crude oil and one for natural gas. The crude oil is delivered to the inlet of a processing center and control is passed through a custodian to the customer at that point. We are paid for crude oil at the inlet plus or minus an adjustment for quality. Our natural gas is metered at the inlet of a transportation pipeline and control is passed at that point. We record natural gas sales at the delivery point to the customer, net of any pricing differentials. There is no material inventory remaining at the end of each reporting period. We have previously deducted any transportation costs, processing fees, or adjustments from revenue and recorded the net amount. Under the new revenue guidance, on January 1, 2018, we now record the gross amount of the revenue and records any fees, or deductions as expenses. Our revenue excludes any amounts collected on behalf of third parties. During the years ended December 31, 2018 and 2017, we sold $68.2 million and $54.9 million, respectively, of oil to Türkiye Petrol Rafinerileri A.Ş. (“TUPRAS”), a privately-owned oil refinery in Turkey, which represented approximately 96.4%, and 97.0% of our total revenues, respectively.
Share-based compensation	Share-based compensation We follow ASC 718, Compensation—Stock Compensation
Series A Preferred Shares	Series A Preferred Shares On November 4, 2016, we issued 921,000 shares of 12.0% Series A Convertible Redeemable Preferred Shares (the “Series A Preferred Shares”). Of the 921,000 Series A Preferred Shares, (i) 815,000 shares were issued in exchange for $40.75 million of our 13.0% Senior Convertible Notes due 2017 (the “2017 Notes”)
Income taxes	Income taxes We follow the asset and liability method prescribed by ASC 740, Income Taxes As of December 31, 2018 and 2017, we have recorded a $6.7 million and $8.7 million liability, respectively, primarily due to uncertain tax positions related to the unwinding of all of our crude oil hedge collars and three-way contracts, which are included in long-term accrued liabilities on our consolidated balance sheet. We do not believe there will be any material changes in our unrecognized tax positions over the next twelve months. Our policy is that we recognize interest and penalties accrued on any unrecognized tax positions as a component of income tax expense. We are a Bermuda exempted company, and under current Bermuda law, we are not subject to tax on profits, income or dividends, nor is there any capital gains tax applicable to us in Bermuda.
Comprehensive income	Comprehensive income We follow ASC 220, Comprehensive Income
Business combinations	Business combinations We follow ASC 805, Business Combinations Consolidation
Per share information	Per share information Basic per share amounts are calculated using the weighted average common shares outstanding during the year, excluding unvested restricted stock units. We use the treasury stock method to determine the dilutive effect of stock options and other dilutive instruments. Under the treasury stock method, only “in the money” dilutive instruments impact the diluted calculations in computing diluted earnings per share. Diluted calculations reflect the weighted average incremental common shares that would be issued upon exercise of dilutive options assuming the proceeds would be used to repurchase shares at average market prices for the period.
New accounting pronouncements	In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date. We adopted ASU 2014-09 on January 1, 2018 using the modified retrospective approach. We have a small number of contracts with customers and have identified transactions within the scope of the standard. As a result of adoption of ASU 2014-09, we have determined that it will change our method of recording certain transportation and processing charges that were previously recorded as a reduction of revenues to record such charges as an expense under the new standard. The result of this change was an increase to both revenue and expenses of $4.7 million for the twelve months ended December 31, 2018. The application of the new standard has no impact on our retained earnings and no impact to our net income on an ongoing basis. During the twelve months ended December 31, 2017, this standard would have increased both revenue and expenses by $4.4 million. Contracts for the sale of natural gas and crude oil are evidenced by (1) base contracts for the sale and purchase of natural gas or crude oil, which document the general terms and conditions for the sale, and (2) transaction confirmations, which document the terms of each specific sale. Revenue is measured based on consideration specified in the contract with the customer. We recognize revenue in the amount that reflects the consideration we expect to be entitled to in exchange for transferring control of those goods to the customer. Revenues are recognized for the sale of our net share of production volumes. Sales on behalf of other working interest owners and royalty interest owners are not recognized as revenues. The contract consideration in our contracts are typically allocated to specific performance obligations in the contract according to the price stated in the contract, which usually sets the base oil and natural gas prices based on benchmark prices based on volumes and adjustments for product quality. Payment is generally received one or two months after the sale has occurred. The following table displays the disaggregation of revenue by product type for the twelve months ended December 31, 2018 and 2017: 2018 2017 (in thousands) Oil $ 69,207 $ 58,109 Natural gas 1,061 1,807 Total revenue from customers $ 70,268 $ 59,916 All of our revenues from contracts with customers represent products transferred at the point in time control is transferred to the customer and are generated in Turkey. Transaction price allocated to remaining performance obligations . A significant number of our product sales are short-term in nature with a contract term of one year or less. For those contracts, we have utilized the practical expedient exempting us from disclosure of the transaction price allocated to remaining performance obligations if the performance obligation is part of a contract that has an original expected duration of one year or less. Contract balances . Receivables from contracts with customers are recorded when the right to consideration becomes unconditional, generally when control of the product has been transferred to the customer. Receivables from contracts with customers were $12.9 million and $15.8 million as of December 31, 2018 and December 31, 2017, respectively, and are reported in accounts receivable, net on our consolidated balance sheets. We currently have no assets or liabilities related to our revenue contracts, including no upfront or rights to deficiency payments. Practical expedients . We have made use of certain practical expedients in adopting the new revenue standard, including the value of unsatisfied performance obligations are not disclosed for (i) contracts with an original expected length of one year or less, (ii) contracts for which we recognize revenue at the amount to which we have the right to invoice, (iii) variable consideration which is allocated entirely to a wholly unsatisfied performance obligation and meets the variable allocation criteria in the standard and (iv) only contracts that are not completed at transition. We have not adjusted the promised amount of consideration for the effects of a significant financing component if we expect, at contract inception, that the period between when we transfer a promised good or service to the customer and when the customer pays for that good or service will be one year or less. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash In May 2017, the FASB issued ASU 2017-09, Scope of Modification Accounting Compensation – Stock Compensation In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging (Topic 815) We have reviewed other recently issued, but not yet adopted, accounting standards in order to determine their effects, if any, on our consolidated results of operations, financial position and cash flows. Based on that review, we believe that none of these pronouncements will have a significant effect on current or future earnings or operations.

New Accounting Pronouncements (

New Accounting Pronouncements (Tables)	12 Months Ended
	Dec. 31, 2018
Accounting Changes And Error Corrections [Abstract]
Summary of Disaggregation of Revenue	The following table displays the disaggregation of revenue by product type for the twelve months ended December 31, 2018 and 2017: 2018 2017 (in thousands) Oil $ 69,207 $ 58,109 Natural gas 1,061 1,807 Total revenue from customers $ 70,268 $ 59,916

Series A Preferred Shares (Tabl

Series A Preferred Shares (Tables)	12 Months Ended
	Dec. 31, 2018
Temporary Equity Disclosure [Abstract]
Schedule of Redemption Prices	The redemption prices for the 12-month period starting on the date below are: Period Commencing Redemption Price November 4, 2020 105.000% November 4, 2021 103.000% November 4, 2022 101.000% November 4, 2023 and thereafter 100.000%

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Capitalized Costs under Successful Efforts Method for Oil and Natural Gas Properties	The following table sets forth the capitalized costs under the successful efforts method for oil and natural gas properties: 2018 2017 (in thousands) Oil and natural gas properties, proved: Turkey $ 162,494 $ 193,111 Bulgaria 512 536 Total oil and natural gas properties, proved 163,006 193,647 Oil and natural gas properties, unproved: Turkey 14,965 24,445 Bulgaria 730 - Total oil and natural gas properties, unproved 15,695 24,445 Gross oil and natural gas properties 178,701 218,092 Accumulated depletion (100,582 ) (123,225 ) Net oil and natural gas properties $ 78,119 $ 94,867
Historical Cost of Equipment and Other Property on Gross Basis with Accumulated Depreciation	The historical cost of equipment and other property, presented on a gross basis with accumulated depreciation, is summarized as follows: 2018 2017 (in thousands) Other equipment $ 1,240 $ 1,764 Land 149 – Inventory 6,791 4,619 Gas gathering system and facilities 194 135 Vehicles 336 343 Leasehold improvements, office equipment and software 5,698 7,214 Gross equipment and other property 14,408 14,075 Accumulated depreciation (5,268 ) (5,958 ) Net equipment and other property $ 9,140 $ 8,118

Derivative instruments (Tables)

Derivative instruments (Tables)	12 Months Ended
	Dec. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Fair Value of Derivative Instruments of Future Crude Oil Production	At December 31, 2017, we had outstanding commodity derivative contracts with respect to our future crude oil production as set forth in the tables below: Fair Value of Derivative Instruments as of December 31, 2017 Collars Weighted Average Weighted Minimum Average Quantity Price Maximum Price Estimated Fair Type Period (Bbl/day) (per Bbl) (per Bbl) Value of Liability (in thousands) Collar January 1, 2018— February 28, 2018 458 $ 50.00 $ 61.50 $ (178 ) Collar January 1, 2018— March 31, 2018 500 $ 47.00 $ 59.65 (376 ) Collar January 1, 2018— May 31, 2018 298 $ 47.50 $ 61.00 (286 ) Collar January 1, 2018— June 30, 2018 746 $ 47.50 $ 57.10 (1,375 ) Total Estimated Fair Value of Liability $ (2,215 )
Summary of Gross Fair Value of Commodity Derivative Instruments by Balance Sheet Classification	The following table summarizes both: (i) the gross fair value of our commodity derivative instruments by the appropriate balance sheet classification even when the commodity derivative instruments are subject to netting arrangements and qualify for net presentation in our consolidated balance sheets at December 31, 2017, and (ii) the net recorded fair value as reflected on our consolidated balance sheets at December 31, 2017. At December 31, 2018, we did not have any commodity or foreign exchange derivative contracts. As of December 31, 2017 Gross Amount Net Amount of Gross Offset in the Assets Amount of Consolidated Presented in the Recognized Balance Consolidated Underlying Commodity Location on Balance Sheet Assets Sheet Balance Sheet (in thousands) Crude oil Current liabilities $ 2,215 $ – $ 2,215

Asset Retirement obligations (T

Asset Retirement obligations (Tables)	12 Months Ended
	Dec. 31, 2018
Asset Retirement Obligation Disclosure [Abstract]
Changes in Asset Retirement Obligations	The following table summarizes the changes in our ARO for the years ended December 31, 2018 and 2017: 2018 2017 (in thousands) Asset retirement obligations at beginning of period $ 4,727 $ 4,833 Liabilities settled – (37 ) Foreign exchange change effect (1,270 ) (259 ) Additions 1,036 – Accretion expense 174 190 Asset retirement obligations at end of period 4,667 4,727 Long-term portion $ 4,667 $ 4,727

Loans payable (Tables)

Loans payable (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Debt	As of the dates indicated, our third-party debt consisted of the following: December 31, December 31, 2018 2017 Fixed and floating rate loans (in thousands) Term Loan (1) $ 22,000 $ 28,625 Loans payable 22,000 28,625 Less: current portion 22,000 15,625 Long-term portion $ – $ 13,000 _______________________________________________________________________________________________________________ (1) Includes 2018, 2017 and 2016 Term Loans.

Shareholders' equity (Tables)

Shareholders' equity (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Restricted Stock Units Activity	Share-based compensation of approximately $0.5 million and $0.7 million Number of RSUs (in thousands) Weighted Average Grant Date Fair Value Per RSU Unvested RSUs outstanding at December 31, 2017 513 $ 1.38 Granted 311 1.55 Forfeited (7 ) 1.18 Vested (363 ) 1.49 Unvested RSUs outstanding at December 31, 2018 454 $ 1.42
Basic and Diluted Earnings Per Common Share Computations	The following table presents the basic and diluted earnings per common share computations: (in thousands, except per share amounts) 2018 2017 Net loss $ (5,216 ) $ (23,875 ) Basic net loss per common share: Shares: Weighted average common shares outstanding 50,505 48,196 Basic net loss per common share: $ (0.10 ) $ (0.50 ) Diluted net loss per common share: Shares: Weighted average shares outstanding 50,505 48,196 Dilutive effect of: Restricted share units – – 2017 Notes – – Weighted average common and common equivalent shares outstanding 50,505 48,196 Diluted net loss per common share: $ (0.10 ) $ (0.50 )

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Reconciliation of Bermuda Income Tax Expense to Actual Income Tax Expense	The income tax provision differs from the amount that would be obtained by applying the Bermuda statutory income tax rate of 0% for 2018 and 2017 to income (loss) from operations as follows: 2018 2017 (in thousands except rates) Statutory rate 0.00 % 0.00 % Income (loss) before income taxes $ 4,458 $ (18,446 ) Increase (decrease) resulting from: Foreign tax rate differentials $ 4,720 $ 945 Uncertain tax position 935 1,050 Unremitted earnings 2,927 1,677 Change in valuation allowance (4,743 ) 640 Expiration of non-capital tax loss carryovers 4,793 792 Other 1,042 325 Total $ 9,674 $ 5,429
Components of Net Deferred Income Tax Liability	The components of the net deferred income tax liability at December 31, 2018 and 2017 were as follows: 2018 2017 (in thousands) Deferred tax assets Property and equipment $ 609 $ 1,279 Unrealized gains on derivative contracts 432 Timing of accruals 574 132 Non-capital loss carryovers 13,261 16,502 Valuation allowance (13,261 ) (17,731 ) Other – 47 Total deferred tax assets $ 1,183 $ 661 Deferred tax liabilities Property and equipment $ (9,728 ) $ (10,044 ) Unremitted earnings (9,401 ) (9,631 ) Timing of accruals (2,368 ) (597 ) Total deferred tax liabilities (21,497 ) (20,272 ) Net deferred tax liabilities $ (20,314 ) $ (19,611 ) Components of net deferred tax liabilities Non-current assets $ 1,183 $ 661 Non-current liabilities (21,497 ) (20,272 ) Net deferred tax liabilities $ (20,314 ) $ (19,611 )
Schedule of Unrecognized Tax Benefits	The unrecognized tax benefits at December 31, 2018 and 2017 were as follows: 2018 2017 (in thousands) Unrecognized tax benefits at beginning of period $ 8,663 $ 8,079 Gross increases - tax positions in prior period 935 1,125 Foreign exchange change effect (2,884 ) (541 ) Unrecognized tax benefits at end of period $ 6,714 $ 8,663

Segment information (Tables)

Segment information (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Financial Information of Geographic Segments	In accordance with ASC 280, Segment Reporting Corporate Turkey Bulgaria Total (in thousands) For the year ended December 31, 2018 Total revenues $ – $ 70,789 $ – $ 70,789 Production – 10,649 120 10,769 Transportation costs – 4,665 – 4,665 Exploration, abandonment, and impairment – 401 – 401 Seismic and other exploration – 488 1 489 General and administrative 9,222 5,344 153 14,719 Depreciation, depletion and amortization 142 13,917 – 14,059 Accretion of asset retirement obligations – 151 23 174 Total costs and expenses 9,364 35,615 297 45,276 Operating (loss) income (9,364 ) 35,174 (297 ) 25,513 Interest and other expense (7,026 ) (3,022 ) – (10,048 ) Interest and other income 184 897 1 1,082 Loss on commodity derivative contracts – (1,797 ) – (1,797 ) Foreign exchange gain (loss) (351 ) (9,932 ) (9 ) (10,292 ) (Loss) income before income taxes (16,557 ) 21,320 (305 ) 4,458 Income tax expense – (9,674 ) – (9,674 ) Net loss $ (16,557 ) $ 11,646 $ (305 ) $ (5,216 ) Total assets at December 31, 2018 $ 8,358 $ 122,325 $ 1,917 $ 132,600 Capital expenditures for the year ended December 31, 2018 $ – $ 23,517 $ – $ 23,517 For the year ended December 31, 2017 Total revenues $ – $ 56,639 $ – $ 56,639 Production 36 12,136 77 12,249 Exploration, abandonment, and impairment – 934 – 934 Cost of purchased natural gas – 568 – 568 Seismic and other exploration – 4,723 – 4,723 General and administrative 6,739 5,729 349 12,817 Depreciation, depletion and amortization 188 16,737 – 16,925 Accretion of asset retirement obligations – 169 21 190 Total costs and expenses 6,963 40,996 447 48,406 Operating (loss) income (6,963 ) 15,643 (447 ) 8,233 Loss on sale of TBNG (15,226 ) – – (15,226 ) Interest and other expense (7,794 ) (1,044 ) – (8,838 ) Interest and other income 250 847 1 1,098 Loss on commodity derivative contracts – (1,852 ) – (1,852 ) Foreign exchange gain (loss) 365 (2,239 ) 13 (1,861 ) (Loss) income before income taxes (29,368 ) 11,355 (433 ) (18,446 ) Income tax expense – (5,429 ) – (5,429 ) Net loss $ (29,368 ) $ 5,926 $ (433 ) $ (23,875 ) Total assets at December 31, 2017 $ 61,167 $ 109,699 $ (10,216 ) $ 160,650 Capital expenditures for the year ended December 31, 2017 $ – $ 15,854 $ – $ 15,854

Financial instruments (Tables)

Financial instruments (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Valuation of Financial Liabilities	The following table summarizes the valuation of our financial liabilities as of December 31, 2018: Fair Value Measurement Classification Quoted Prices in Active Markets for Identical Assets or Significant Other Significant Liabilities Observable Inputs Unobservable Inputs (Level 1) (Level 2) (Level 3) Total (in thousands) Liabilities: 2017 Term Loan – – (11,938 ) (11,938 ) 2018 Term Loan – – (8,192 ) (8,192 ) Total $ – $ – $ (20,130 ) $ (20,130 ) The following table summarizes the valuation of our financial liabilities as of December 31, 2017: Fair Value Measurement Classification Quoted Prices in Active Markets for Identical Assets or Significant Other Significant Liabilities Observable Inputs Unobservable Inputs (Level 1) (Level 2) (Level 3) Total (in thousands) Measured on a recurring basis Liabilities: Commodity derivative contracts $ – $ (2,215 ) $ – $ (2,215 ) Disclosed but not carried at fair value Liabilities: 2017 Term Loan – – (16,613 ) (16,613 ) 2016 Term Loan – – (7,866 ) (7,866 ) Total $ – $ (2,215 ) $ (24,479 ) $ (26,694 )

Commitments (Tables)

Commitments (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Aggregate Annual Commitments Other Than Debt	Our aggregate annual commitments, other than our loans payable, as of December 31, 2018 were as follows: Payments Due By Year Total 2019 2020 2021 2022 2023 Thereafter (in thousands) Series A Preferred Shares dividends (1) $ 37,822 $ 5,526 $ 5,526 $ 5,526 $ 5,526 $ 5,526 $ 10,192 Interest 800 800 - - - - - Leases 3,251 963 710 636 626 316 - Total $ 41,873 $ 7,289 $ 6,236 $ 6,162 $ 6,152 $ 5,842 $ 10,192 (1) Dividends on the Series A Preferred Shares may be paid by us, in our sole discretion, in cash at a rate of 12% per annum or in common shares at a rate of 16% per annum or in a combination of cash and common shares. The amounts in the table assume that we pay all future dividend payments solely in cash.

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Accounts Receivable and Accounts Payable	The following table summarizes related party accounts receivable and accounts payable as of December 31, 2018 and December 31, 2017: 2018 2017 (in thousands) Related party accounts receivable: Riata Management Service Agreement $ 526 $ 576 PSI MSA 352 447 Total related party accounts receivable $ 878 $ 1,023 Related party accounts payable: Riata Management Service Agreement $ 372 $ 341 PSI MSA 2,439 2,119 Board of Directors 111 – Interest payable on Series A Preferred Shares – 681 Total related party accounts payable $ 2,922 $ 3,141

Divestitures and Discontinued_2

Divestitures and Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2018
Discontinued Operations And Disposal Groups [Abstract]
Reclassification of Accumulated Foreign Currency Translation Adjustment Realized Into Earnings from Accumulated Other Comprehensive Loss	The loss related to the reclassification of the TBNG accumulated foreign currency translation adjustment that was realized into earnings from accumulated other comprehensive loss within shareholders’ equity. The calculation of the loss on sale is presented below: Loss on Sale (in thousands) Total cash proceeds for TBNG $ 20,707 Less: TBNG net assets 12,869 Gain on sale before accumulated foreign currency translation adjustment 7,838 Less: TBNG accumulated foreign currency translation adjustment (23,064 ) Net loss on sale of TBNG $ (15,226 )

General - Additional Informatio

General - Additional Information (Detail) $ in Millions	Feb. 24, 2017USD ($)	Dec. 31, 2018Segment	Mar. 22, 2019
Nature Of Business [Line Items]
Number of operating segments | Segment		2
Purchase price reduction amount	$ 0.2
Thrace Basin Natural Gas (Turkiye) Corporation [Member]
Nature Of Business [Line Items]
Gross proceeds on sale of ownership interests	20.7
Net cash proceeds on sale of ownership interests	$ 16.1
Subsequent Event [Member]
Nature Of Business [Line Items]
Percentage of common shares owned			48.00%

Liquidity - Additional Informat

Liquidity - Additional Information (Detail) - USD ($)	Dec. 31, 2018	May 28, 2018	Dec. 31, 2017	Dec. 31, 2016
Liquidity [Line Items]
Long-term debt	$ 0		$ 13,000,000
Short-term debt	22,000,000		15,625,000
Cash	9,892,000		$ 18,926,000	$ 10,000,000
Working capital surplus	$ 2,500,000
2018 Term Loan [Member] | Credit Agreement [Member] | DenizBank [Member]
Liquidity [Line Items]
Line Of Credit Facility Maximum Borrowing Capacity		$ 10,000,000

Significant Accounting Polici_2

Significant Accounting Policies - Additional information (Detail)	Nov. 04, 2016USD ($)$ / sharesshares	Dec. 31, 2018USD ($)Contract	Dec. 31, 2017USD ($)
Significant Accounting Policies [Line Items]
Allowance for doubtful accounts		$ 500,000	$ 500,000
Determination of exploratory well's ability to produce, term		1 year
Number of sales contracts consists revenue | Contract		2
Liability for Uncertain Tax Positions, Current		$ 6,700,000	8,700,000
Series A Preferred Shares [Member]
Significant Accounting Policies [Line Items]
Preferred shares, issued | shares	921,000
Preferred stock, dividend rate, percentage	12.00%
Preferred stock, shares issued value per share | $ / shares	$ 50
Series A Preferred Shares [Member] | 13.0% Senior Convertible Notes Due 2017 [Member]
Significant Accounting Policies [Line Items]
Preferred shares, issued | shares	815,000
Proceeds from issuance of preferred stock	$ 40,750,000
Convertible preferred shares issued upon conversion | shares	20
Value of principal amount on conversion	$ 1,000,000
Series A Preferred Shares [Member] | 13.0% Senior Convertible Notes Due 2017 [Member] | Convertible Debt [Member]
Significant Accounting Policies [Line Items]
Debt instrument interest rate stated percentage	13.00%
Series A Preferred Shares [Member] | 13.0% Senior Convertible Notes Due 2017 [Member] | Certain Holders [Member]
Significant Accounting Policies [Line Items]
Preferred shares, issued | shares	106,000
Proceeds from issuance of preferred stock	$ 5,300,000
TUPRAS [Member]
Significant Accounting Policies [Line Items]
Allowance for doubtful accounts		0
Oil and Natural Gas Sales [Member]
Significant Accounting Policies [Line Items]
Sales revenue, crude oil and natural gas		70,268,000	55,523,000
Oil and Natural Gas Sales [Member] | TUPRAS [Member]
Significant Accounting Policies [Line Items]
Sales revenue, crude oil and natural gas		$ 68,200,000	$ 54,900,000
Sales Revenue, Goods, Net [Member] | Revenue from Rights Concentration Risk [Member]
Significant Accounting Policies [Line Items]
Concentration Risk, Percentage		96.40%	97.00%
Minimum [Member]
Significant Accounting Policies [Line Items]
Equipment and other property, estimated useful lives		3 years
Maximum [Member]
Significant Accounting Policies [Line Items]
Equipment and other property, estimated useful lives		7 years

New Accounting Pronouncements -

New Accounting Pronouncements - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Increased in expenses	$ 45,276,000	$ 48,406,000
Accumulated deficit	(427,319,000)	(422,103,000)
Impact on net income	(5,216,000)	(23,875,000)
Receivables from contracts with customers	12,912,000	15,808,000
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Operating lease, right-of-use asset	2,700,000
Operating lease, liability	2,700,000
Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Sales revenue, crude oil and natural gas	$ 70,268,000	59,916,000
Revenue, remaining performance obligation, optional exemption, performance obligation	true
Receivables from contracts with customers	$ 12,900,000	15,800,000
Assets related to revenue contracts	0
Liabilities related to revenue contracts	0
Upfront or rights to deficiency payments from contract with customers	$ 0
Revenue, practical expedient, initial application and transition, nondisclosure of transaction price allocation to remaining performance obligation	true
Revenue, practical expedient, financing component	true
Accounting Standards Update 2014-09 [Member] | Minimum [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Term of payment received after sale	1 month
Accounting Standards Update 2014-09 [Member] | Maximum [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Term of payment received after sale	2 months
Transaction price allocated to remaining performance obligations contract term	1 year
Exemption period from disclosure	1 year
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Sales revenue, crude oil and natural gas	$ 4,700,000	4,400,000
Increased in expenses	4,700,000	$ 4,400,000
Accumulated deficit	0
Impact on net income	$ 0

New Accounting Pronouncements_2

New Accounting Pronouncements - Summary of Disaggregation of Revenue (Detail) - Accounting Standards Update 2014-09 [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of revenue
Total revenue from customers	$ 70,268	$ 59,916
Oil [Member]
Disaggregation of revenue
Total revenue from customers	69,207	58,109
Natural Gas [Member]
Disaggregation of revenue
Total revenue from customers	$ 1,061	$ 1,807

Series A Preferred Shares - Add

Series A Preferred Shares - Additional Information (Detail)	Dec. 31, 2018USD ($)shares	Oct. 02, 2017	Mar. 31, 2017USD ($)shares	Jan. 02, 2017USD ($)	Nov. 04, 2016USD ($)Director$ / sharesshares	Dec. 31, 2018USD ($)shares	Dec. 31, 2017USD ($)
Series A Preferred Shares [Member]
Redeemable Noncontrolling Interest [Line Items]
Preferred shares, issued					921,000
Convertible preferred shares issued upon conversion					45.754
Preferred stock, shares issued value per share | $ / shares					$ 50
Preferred shares, value | $	$ 21,300,000					$ 21,300,000	$ 21,300,000
Convertible preferred stock, terms of conversion						each Series A Preferred Share may be converted at any time, at the option of the holder, into 45.754 common shares of the Company (which is equal to an initial conversion price of approximately $1.0928 per common share and is subject to customary adjustment for stock splits, stock dividends, recapitalizations or other fundamental changes).
Conversion of stock, per share | $ / shares					$ 1.0928
Preferred stock redemption period end date					Nov. 4, 2024
Preferred stock redemption period start date					Nov. 4, 2020
Maximum closing sale price of common shares on conversion price					150.00%
Preferred stock, redemption description						At any time on or after November 4, 2020, we may redeem all or a portion of the Series A Preferred Shares at the redemption prices listed below (expressed as a percentage of the liquidation preference amount per share) plus accrued and unpaid dividends to the date of redemption, if the closing sale price of the common shares equals or exceeds 150% of the conversion price then in effect for at least 10 trading days (whether or not consecutive) in a period of 20 consecutive trading days, including the last trading day of such 20 trading day period, ending on, and including, the trading day immediately preceding the business day on which we issue a notice of optional redemption.
Change in control, offering redemption period					120 days
Preferred stock, dividend payment terms	Each common share was issued at a value of $1.0188 per common share, which was equal to the 15-day volume weighted average price through the close of trading of the common shares on the NYSE American exchange on December 14, 2018.	Each common share was issued at a value of $0.7108 per common share, which was equal to the 15-day volume weighted average price through the close of trading of the common shares on the NYSE American exchange on September 13, 2017				Dividends on the Series A Preferred Shares are payable quarterly at our election in cash, common shares or a combination of cash and common shares at an annual dividend rate of 12.0% of the liquidation preference if paid all in cash or 16.0% of the liquidation preference if paid in common shares. If paid partially in cash and partially in common shares, the dividend rate on the cash portion is 12.0%, and the dividend rate on the common share portion is 16.0%.
Preferred stock, dividend rate, percentage					12.00%
Dividend payment description						Dividends are payable quarterly, on June 30, September 30, December 31, and March 31 of each year.
Preferred stock dividends paid | $						$ 5,300,000
Preferred stock accrued dividends | $							6,000,000
Preferred stock voting rights						no voting rights
Certificate of designation description						The Certificate of Designation also provides that without the approval of the holders of a majority of the outstanding Series A Preferred Shares, we will not issue indebtedness for money borrowed or other securities which are senior to the Series A Preferred Shares in excess of the greater of (i) $100 million or (ii) 35% of our PV-10 of proved reserves as disclosed in our most recent independent reserve report filed or furnished by us on EDGAR.
Maximum amount of indebtedness for borrowed money allowed under certificate of designation | $					$ 100,000,000
PV10 reserve value percentage					35.00%
Series A Preferred Shares [Member] | Maximum [Member]
Redeemable Noncontrolling Interest [Line Items]
Right to elect number of directors | Director					2
Series A Preferred Shares [Member] | Minimum [Member]
Redeemable Noncontrolling Interest [Line Items]
Right to elect number of directors | Director					1
Series A Preferred Shares [Member] | Dividend Paid in Cash [Member]
Redeemable Noncontrolling Interest [Line Items]
Preferred stock, dividend rate, percentage					12.00%
Series A Preferred Shares [Member] | Dividend Paid in Common Shares [Member]
Redeemable Noncontrolling Interest [Line Items]
Preferred stock, dividend rate, percentage					16.00%
Series A Preferred Shares [Member] | 13.0% Convertible Notes Due 2017 [Member]
Redeemable Noncontrolling Interest [Line Items]
Preferred shares, issued					815,000
Amount of notes exchanged | $					$ 40,750,000
Convertible preferred shares issued upon conversion					20
Value of principal amount on conversion | $					$ 1,000
Redemption of notes | $				$ 4,300,000
Series A Preferred Shares [Member] | Certain Holders [Member] | 13.0% Convertible Notes Due 2017 [Member]
Redeemable Noncontrolling Interest [Line Items]
Preferred shares, issued					106,000
Proceeds from issuance of preferred stocks | $					$ 5,300,000
Series A Preferred Shares [Member] | Two Director [Member]
Redeemable Noncontrolling Interest [Line Items]
Preferred shares, outstanding					400,000
Series A Preferred Shares [Member] | One Director [Member] | Maximum [Member]
Redeemable Noncontrolling Interest [Line Items]
Preferred shares, outstanding					80,000
Series A Preferred Shares [Member] | One Director [Member] | Minimum [Member]
Redeemable Noncontrolling Interest [Line Items]
Preferred shares, outstanding					399,999
Related Party [Member]
Redeemable Noncontrolling Interest [Line Items]
Preferred shares, issued			84,000
Proceeds from issuance of preferred stocks | $			$ 4,200,000
Related Party [Member] | Series A Preferred Shares [Member]
Redeemable Noncontrolling Interest [Line Items]
Preferred shares, issued	495,000					495,000
Preferred shares, value | $	$ 24,750,000					$ 24,750,000	$ 24,750,000
Preferred shares, outstanding	495,000					495,000

Series A Preferred Shares - Sch

Series A Preferred Shares - Schedule of Redemption Prices (Detail) - Series A Preferred Shares [Member]	Nov. 04, 2016
Redeemable Noncontrolling Interest [Line Items]
November 4, 2020	105.00%
November 4, 2021	103.00%
November 4, 2022	101.00%
November 4, 2023 and thereafter	100.00%

Property and Equipment - Capita

Property and Equipment - Capitalized Costs under Successful Efforts Method for Oil and Natural Gas Properties (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Oil and natural gas properties, proved	$ 163,006	$ 193,647
Oil and natural gas properties, unproved	15,695	24,445
Gross oil and natural gas properties	178,701	218,092
Accumulated depletion	(100,582)	(123,225)
Net oil and natural gas properties	78,119	94,867
Turkey [Member]
Property Plant And Equipment [Line Items]
Oil and natural gas properties, proved	162,494	193,111
Oil and natural gas properties, unproved	14,965	24,445
Bulgaria [Member]
Property Plant And Equipment [Line Items]
Oil and natural gas properties, proved	512	$ 536
Oil and natural gas properties, unproved	$ 730

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Proved development wells excluded from depletion	$ 500	$ 500
Acquisition costs of proved properties	6,500	11,200
Well costs and additional development costs	53,400	58,700
Exploratory dry hole costs	300	800
Capitalized exploratory cost greater than one year	0
Inventory	5,167	7,494
Inventory [Member]
Property Plant And Equipment [Line Items]
Property plant and equipment excluded from depreciation	$ 12,000	12,100
Pinar - 1 well [Member] | Turkey [Member]
Property Plant And Equipment [Line Items]
Capitalized exploratory cost greater than one year		$ 4,000

Property and Equipment - Histor

Property and Equipment - Historical Cost of Equipment and Other Property on Gross Basis with Accumulated Depreciation (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Gross equipment and other property	$ 14,408	$ 14,075
Accumulated depreciation	(5,268)	(5,958)
Net equipment and other property	9,140	8,118
Other equipment [Member]
Property Plant And Equipment [Line Items]
Gross equipment and other property	1,240	1,764
Land [Member]
Property Plant And Equipment [Line Items]
Gross equipment and other property	149
Inventory [Member]
Property Plant And Equipment [Line Items]
Gross equipment and other property	6,791	4,619
Gas gathering system and facilities [Member]
Property Plant And Equipment [Line Items]
Gross equipment and other property	194	135
Vehicles [Member]
Property Plant And Equipment [Line Items]
Gross equipment and other property	336	343
Leasehold improvements, office equipment and software [Member]
Property Plant And Equipment [Line Items]
Gross equipment and other property	$ 5,698	$ 7,214

Derivative Instruments - Additi

Derivative Instruments - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)DerivativeContract	Dec. 31, 2017USD ($)DerivativeContract
Derivatives Fair Value [Line Items]
Loss on derivative contracts | $	$ 1,797	$ 1,852
Foreign Exchange Rates [Member]
Derivatives Fair Value [Line Items]
Outstanding derivative contracts	0	0
Crude Oil [Member] | Commodity [Member]
Derivatives Fair Value [Line Items]
Outstanding derivative contracts	0

Derivative Instruments - Fair V

Derivative Instruments - Fair Value of Derivative Instruments of Future Crude Oil Production (Detail) - Commodity Price [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)$ / bblbbl
Derivatives Fair Value [Line Items]
Estimated Fair Value of Liability | $	$ (2,215)
Collar - January 1, 2018 - February 28, 2018 [Member]
Derivatives Fair Value [Line Items]
Quantity (Bbl/day) | bbl	458
Collars Weighted Average Minimum Price (per Bbl)	50
Weighted Average Maximum Price (per Bbl)	61.50
Estimated Fair Value of Liability | $	$ (178)
Collar - January 1, 2018 - March 31, 2018 [Member]
Derivatives Fair Value [Line Items]
Quantity (Bbl/day) | bbl	500
Collars Weighted Average Minimum Price (per Bbl)	47
Weighted Average Maximum Price (per Bbl)	59.65
Estimated Fair Value of Liability | $	$ (376)
Collar - January 1, 2018 - May 31, 2018 [Member]
Derivatives Fair Value [Line Items]
Quantity (Bbl/day) | bbl	298
Collars Weighted Average Minimum Price (per Bbl)	47.50
Weighted Average Maximum Price (per Bbl)	61
Estimated Fair Value of Liability | $	$ (286)
Collar - January 1, 2018 - June 30, 2018 [Member]
Derivatives Fair Value [Line Items]
Quantity (Bbl/day) | bbl	746
Collars Weighted Average Minimum Price (per Bbl)	47.50
Weighted Average Maximum Price (per Bbl)	57.10
Estimated Fair Value of Liability | $	$ (1,375)

Derivative Instruments - Summar

Derivative Instruments - Summary of Gross Fair Value of Commodity Derivative Instruments by Balance Sheet Classification (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Derivatives Fair Value [Line Items]
Net Amount of Liabilities Presented in the Consolidated Balance Sheet, Current Liabilities	$ 2,215
Commodity [Member]
Derivatives Fair Value [Line Items]
Gross Amount of Recognized Liabilities	2,215
Crude Oil [Member] | Current Liabilities [Member] | Commodity [Member]
Derivatives Fair Value [Line Items]
Gross Amount of Recognized Liabilities	2,215
Net Amount of Liabilities Presented in the Consolidated Balance Sheet, Current Liabilities	$ 2,215

Asset Retirement Obligations -

Asset Retirement Obligations - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Asset Retirement Obligations [Line Items]
Asset retirement obligation, net present value	$ 4,667	$ 4,727	$ 4,833
Asset retirement obligation, undiscounted value	$ 8,200
Turkey [Member]
Asset Retirement Obligations [Line Items]
Inflation rate per annum used to adjust asset retirement obligation	12.65%
Turkey [Member] | Measurement Input, Discount Rate [Member]
Asset Retirement Obligations [Line Items]
Credit-adjusted risk-free rate used to discount asset retirement obligation	0.0755

Asset Retirement Obligations _2

Asset Retirement Obligations - Changes in Asset Retirement Obligations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Asset Retirement Obligation Disclosure [Abstract]
Asset retirement obligations at beginning of period	$ 4,727	$ 4,833
Liabilities settled		(37)
Foreign exchange change effect	(1,270)	(259)
Additions	1,036
Accretion expense	174	190
Asset retirement obligations at end of period	4,667	4,727
Long-term portion	$ 4,667	$ 4,727

Loans Payable - Debt (Detail)

Loans Payable - Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Loans payable	$ 22,000	$ 28,625
Less: current portion	22,000	15,625
Long-term portion		13,000
Term Loan [Member]
Debt Instrument [Line Items]
Loans payable	$ 22,000	$ 28,625

Loans Payable - Additional Info

Loans Payable - Additional Information (Detail)

Apr. 27, 2017USD ($)

Oct. 31, 2016Installment

Sep. 30, 2017USD ($)

Jun. 30, 2017USD ($)

Mar. 31, 2017USD ($)

Dec. 31, 2016USD ($)

Dec. 31, 2018USD ($)

Dec. 31, 2017USD ($)

May 28, 2018USD ($)

Nov. 17, 2017USD ($)

Aug. 31, 2016USD ($)

Dec. 30, 2015USD ($)

Line Of Credit Facility [Line Items]

Loans payable

$ 22,000,000

$ 28,625,000

Interest expense

10,048,000

8,838,000

Non-cash Facilities [Member] | DenizBank [Member]

Line Of Credit Facility [Line Items]

Line Of Credit Facility Maximum Borrowing Capacity

$ 20,000,000

Loan Financing Costs [Member]

Line Of Credit Facility [Line Items]

Amortization of Deferred Loan Origination Fees, Net

$ 100,000

100,000

2016 TEMI Term Loan [Member]

Line Of Credit Facility [Line Items]

Debt instrument interest rate stated percentage

5.25%

Debt instrument interest rate basis for effective rate

The 2016 Term Loan bore interest at a fixed rate of 5.25% (plus 0.2625% for Banking and Insurance Transactions Tax per the Turkish government

Debt instrument payment terms

Payable in six monthly installments of $1.25 million each through February 2017 and thereafter in twelve monthly installments of $1.88 million each through February 2018

Amount of each installment payable through February 2017

$ 1,250,000

Amount of each installment payable through February 2018

$ 1,880,000

Line of credit facility, expiration date

Feb. 28, 2018

2016 TEMI Term Loan [Member] | Turkish Banking and Insurance Transactions Tax Rate [Member]

Line Of Credit Facility [Line Items]

Debt instrument basis spread on variable rate

0.2625%

2016 TEMI Term Loan [Member] | Credit Agreement [Member] | DenizBank [Member]

Line Of Credit Facility [Line Items]

Line of credit facility, initiation date

Aug. 31, 2016

Line Of Credit Facility Maximum Borrowing Capacity

$ 30,000,000

Line of credit facility, expiration date

Jun. 30, 2018

Debt instrument, monthly payments

$ 1,380,000

2016 TEMI Term Loan [Member] | Line of Credit [Member] | Mr. Mitchell [Member]

Line Of Credit Facility [Line Items]

Line of credit facility ownership percentage

80.00%

2016 TEMI Term Loan [Member] | Line of Credit [Member] | Mr. Uras [Member]

Line Of Credit Facility [Line Items]

Line of credit facility ownership percentage

20.00%

2017 Term Loan [Member]

Line Of Credit Facility [Line Items]

Debt instrument interest rate stated percentage

6.00%

Debt instrument interest rate basis for effective rate

The 2017 Term Loan bears interest at a fixed rate of 6.0% (plus 0.3% for Banking and Insurance Transactions Tax per the Turkish government) per annum

Debt instrument payment terms

The 2017 Term Loan had a grace period which bore no interest or payments due until July 2018. Thereafter, the 2017 Term Loan is payable in one monthly installment of $1.38 million, nine monthly installments of $1.2 million each through April 2019 and thereafter in eight monthly installments of $1.0 million each through December 2019, with the exception of one monthly installment of $1.2 million occurring in October 2019

Line of credit facility, expiration date

Dec. 31, 2019

2017 Term Loan [Member] | Due until July 2018 [Member]

Line Of Credit Facility [Line Items]

Debt instrument interest rate stated percentage

0.00%

Debt instrument, principal installments

$ 0

2017 Term Loan [Member] | One Monthly Installment Payable through April 2019 [Member]

Line Of Credit Facility [Line Items]

Debt instrument, principal installments

1,380,000

2017 Term Loan [Member] | Nine Monthly Installments Payable through April 2019 [Member]

Line Of Credit Facility [Line Items]

Debt instrument, principal installments

1,200,000

2017 Term Loan [Member] | Eight Monthly Installments Payable through December 2019 [Member]

Line Of Credit Facility [Line Items]

Debt instrument, principal installments

1,000,000

2017 Term Loan [Member] | One Monthly Installment Occurring in October 2019 [Member]

Line Of Credit Facility [Line Items]

Amount of each installment payable occurring in October 2019

$ 1,200,000

2017 Term Loan [Member] | Turkish Banking and Insurance Transactions Tax Rate [Member]

Line Of Credit Facility [Line Items]

Debt instrument basis spread on variable rate

0.30%

2017 Term Loan [Member] | Credit Agreement [Member] | DenizBank [Member]

Line Of Credit Facility [Line Items]

Line of credit facility, initiation date

Nov. 17, 2017

Line Of Credit Facility Maximum Borrowing Capacity

$ 20,400,000

2017 Term Loan [Member] | Line of Credit [Member]

Line Of Credit Facility [Line Items]

Loans payable

$ 13,000,000

2017 Term Loan [Member] | Line of Credit [Member] | Mr. Mitchell [Member]

Line Of Credit Facility [Line Items]

Line of credit facility ownership percentage

80.00%

2017 Term Loan [Member] | Line of Credit [Member] | Mr. Uras [Member]

Line Of Credit Facility [Line Items]

Line of credit facility ownership percentage

20.00%

2017 Term Loan [Member] | Line of Credit [Member] | Mr. Uras [Member]

Line Of Credit Facility [Line Items]

Line of credit facility ownership percentage

100.00%

2018 Term Loan [Member]

Line Of Credit Facility [Line Items]

Debt instrument interest rate stated percentage

7.25%

Debt instrument interest rate basis for effective rate

The 2018 Term Loan bears interest at a fixed rate of 7.25% (plus 0.3% for Banking and Insurance Transactions Tax per the Turkish government) per annum

Debt instrument payment terms

The 2018 Term Loan bears interest at a fixed rate of 7.25% (plus 0.3% for Banking and Insurance Transactions Tax per the Turkish government) per annum

Line of credit facility, expiration date

Dec. 31, 2019

2018 Term Loan [Member] | Due through July 2018 [Member]

Line Of Credit Facility [Line Items]

Debt instrument, principal installments

$ 0

2018 Term Loan [Member] | Five Monthly Installments Payable through December 2018 [Member]

Line Of Credit Facility [Line Items]

Debt instrument, principal installments

200,000

2018 Term Loan [Member] | Four Monthly Installments Payable through April 2019 [Member]

Line Of Credit Facility [Line Items]

Debt instrument, principal installments

500,000

2018 Term Loan [Member] | Four Monthly Installments Payable through August 2019 [Member]

Line Of Credit Facility [Line Items]

Debt instrument, principal installments

1,000,000

2018 Term Loan [Member] | Four Monthly Installments Payable through December 2019 [Member]

Line Of Credit Facility [Line Items]

Debt instrument, principal installments

$ 750,000

2018 Term Loan [Member] | Turkish Banking and Insurance Transactions Tax Rate [Member]

Line Of Credit Facility [Line Items]

Debt instrument basis spread on variable rate

0.30%

2018 Term Loan [Member] | Credit Agreement [Member] | DenizBank [Member]

Line Of Credit Facility [Line Items]

Line of credit facility, initiation date

May 28, 2018

Line Of Credit Facility Maximum Borrowing Capacity

$ 10,000,000

2018 Term Loan [Member] | Line of Credit [Member]

Line Of Credit Facility [Line Items]

Loans payable

$ 9,000,000

2018 Term Loan [Member] | Line of Credit [Member] | Mr. Mitchell [Member]

Line Of Credit Facility [Line Items]

Line of credit facility ownership percentage

80.00%

2018 Term Loan [Member] | Line of Credit [Member] | Mr. Uras [Member]

Line Of Credit Facility [Line Items]

Line of credit facility ownership percentage

20.00%

2018 Term Loan [Member] | Line of Credit [Member] | Mr. Uras [Member]

Line Of Credit Facility [Line Items]

Line of credit facility ownership percentage

100.00%

2016, 2017 and 2018 Term Loan [Member]

Line Of Credit Facility [Line Items]

Interest expense

$ 1,800,000

$ 900,000

13.0% Convertible Notes Due 2017 [Member] | Convertible Debt [Member]

Line Of Credit Facility [Line Items]

Debt instrument interest rate stated percentage

13.00%

Frequency of payments

semi-annually

Debt instrument, maturity date

Jul. 1, 2017

ANBE Note [Member] | TransAtlantic USA [Member]

Line Of Credit Facility [Line Items]

Debt instrument, principal installments

$ 900,000

$ 900,000

$ 900,000

$ 900,000

Number of installments | Installment

4

ANBE Note [Member] | TransAtlantic USA [Member] | Convertible Promissory Note [Member]

Line Of Credit Facility [Line Items]

Line Of Credit Facility Maximum Borrowing Capacity

$ 5,000,000

Debt instrument interest rate stated percentage

13.00%

Line of credit facility borrowing capacity

$ 3,600,000

Extender ANBE Note [Member] | TransAtlantic USA [Member]

Line Of Credit Facility [Line Items]

Debt instrument, maturity date

Sep. 30, 2017

Unsecured lines of credit [Member]

Line Of Credit Facility [Line Items]

Loans payable

$ 0

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2018	Oct. 02, 2017	Aug. 13, 2015	Apr. 24, 2015	Dec. 31, 2014	Dec. 31, 2018	Dec. 31, 2017
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Antidilutive securities excluded from computation of earnings per share amount						42,000,000	43,700,000
Common share purchase warrants issued			233,333	233,333	233,334
Common share purchase	1					1
Common share purchase warrants, exercise price			$ 2.99	$ 5.65	$ 5.99
Warrants [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Common share purchase	1					1
Restricted Stock Units [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Estimated forfeiture rate of RSUs						12.50%
Restricted stock unit, vesting period						4 years
Share-based compensation expense						$ 0.5	$ 0.7
Unrecognized compensation expense	$ 0.3					$ 0.3
Unrecognized compensation expense recognition period						6 months
Series A Preferred Shares [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Aggregate number of common shares issued to preferred share holders as payment of dividend	1,808,001	2,591,384				1,808,001
Common shares issued, price per share	$ 1.0188	$ 0.7108				$ 1.0188
Preferred stock, dividend payment terms	Each common share was issued at a value of $1.0188 per common share, which was equal to the 15-day volume weighted average price through the close of trading of the common shares on the NYSE American exchange on December 14, 2018.	Each common share was issued at a value of $0.7108 per common share, which was equal to the 15-day volume weighted average price through the close of trading of the common shares on the NYSE American exchange on September 13, 2017				Dividends on the Series A Preferred Shares are payable quarterly at our election in cash, common shares or a combination of cash and common shares at an annual dividend rate of 12.0% of the liquidation preference if paid all in cash or 16.0% of the liquidation preference if paid in common shares. If paid partially in cash and partially in common shares, the dividend rate on the cash portion is 12.0%, and the dividend rate on the common share portion is 16.0%.

Shareholders' Equity - Restrict

Shareholders' Equity - Restricted Stock Unit Activity (Detail) - Restricted Stock Units [Member] shares in Thousands	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested RSUs outstanding, beginning balance | shares	513
Granted | shares	311
Forfeited | shares	(7)
Vested | shares	(363)
Unvested RSUs outstanding, ending balance | shares	454
Unvested RSUs, weighted average grant date fair value Per RSU, beginning balance | $ / shares	$ 1.38
Granted, weighted average grant date fair value Per RSU | $ / shares	1.55
Forfeited, weighted average grant date fair value Per RSU | $ / shares	1.18
Vested, weighted average grant date fair value Per RSU | $ / shares	1.49
Unvested RSUs weighted average grant date fair value Per RSU, ending balance | $ / shares	$ 1.42

Shareholders' Equity - Basic an

Shareholders' Equity - Basic and Diluted Earnings Per Common Share Computations (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Net loss	$ (5,216)	$ (23,875)
Weighted average common shares outstanding	50,505	48,196
Basic net loss per common share	$ (0.10)	$ (0.50)
Weighted average shares outstanding	50,505	48,196
Weighted average common and common equivalent shares outstanding	50,505	48,196
Diluted net loss per common share	$ (0.10)	$ (0.50)

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Bermuda Income Tax Expense to Actual Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Statutory rate	0.00%	0.00%
Income (loss) before income taxes	$ 4,458	$ (18,446)
Increase (decrease) resulting from:
Foreign tax rate differentials	4,720	945
Uncertain tax position	935	1,050
Unremitted earnings	2,927	1,677
Change in valuation allowance	(4,743)	640
Expiration of non-capital tax loss carryovers	4,793	792
Other	1,042	325
Total	$ 9,674	$ 5,429

Income Taxes - Components of Ne

Income Taxes - Components of Net Deferred Income Tax Liability (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets
Property and equipment	$ 609	$ 1,279
Unrealized gains on derivative contracts		432
Timing of accruals	574	132
Non-capital loss carryovers	13,261	16,502
Valuation allowance	(13,261)	(17,731)
Other		47
Total deferred tax assets	1,183	661
Deferred tax liabilities
Property and equipment	(9,728)	(10,044)
Unremitted earnings	(9,401)	(9,631)
Timing of accruals	(2,368)	(597)
Total deferred tax liabilities	(21,497)	(20,272)
Net deferred tax liabilities	(20,314)	(19,611)
Components of net deferred tax liabilities
Non-current assets	1,183	661
Non-current liabilities	(21,497)	(20,272)
Net deferred tax liabilities	$ (20,314)	$ (19,611)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) ₺ in Millions, лв in Millions, in Millions	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2018TRY (₺)	Dec. 31, 2017TRY (₺)	Dec. 31, 2015TRY (₺)	Dec. 31, 2018TRY (₺)	Dec. 31, 2018RON ( )	Dec. 31, 2018BGN (лв)	Dec. 31, 2017USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2015TRY (₺)
Income Tax [Line Items]
Valuation allowance	$ 13,261,000							$ 17,731,000
Liability for Uncertain Tax Positions, Current	6,700,000							$ 8,700,000
Unrecognized Tax Benefits, Period Increase (Decrease)	0
13.0% convertible notes due in 2017 [Member] | 2017 Notes [Member]
Income Tax [Line Items]
Notes Payable									$ 55,000,000
Turkish Foreign Subsidiaries [Member]
Income Tax [Line Items]
Withdrew reinvestment assertion | ₺										₺ 135.2
Dividend withholding taxes | ₺		₺ 329.7	₺ 242.1	₺ 135.2
Turkey [Member]
Income Tax [Line Items]
Non-capital tax losses	$ 11,000,000				₺ 57.8
Non-capital tax losses, expiration date	2019	2019
Romania [Member]
Income Tax [Line Items]
Non-capital tax losses	$ 400,000					1.6
Non-capital tax losses, expiration date	2019	2019
Bulgaria [Member]
Income Tax [Line Items]
Non-capital tax losses	$ 5,700,000						лв 9.8
Non-capital tax losses, expiration date	2019	2019
U.S [Member]
Income Tax [Line Items]
Non-capital tax losses	$ 53,700,000
Non-capital tax losses, expiration date	2019	2019

Income Taxes - Schedule of Unre

Income Taxes - Schedule of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Unrecognized tax benefits at beginning of period	$ 8,663	$ 8,079
Gross increases - tax positions in prior period	935	1,125
Foreign exchange change effect	(2,884)	(541)
Unrecognized tax benefits at end of period	$ 6,714	$ 8,663

Segment Information - Additiona

Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018Segment
Segment Reporting [Abstract]
Number of reportable geographic segments	2

Segment Information - Financial

Segment Information - Financial Information of Geographic Segments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total revenues	$ 70,789	$ 56,639
Production	10,769	12,249
Exploration, abandonment and impairment	401	934
Seismic and other exploration	489	4,723
General and administrative	14,719	12,817
Depreciation, depletion and amortization	14,059	16,925
Accretion of asset retirement obligations	174	190
Total costs and expenses	45,276	48,406
Operating income	25,513	8,233
Loss on sale of TBNG		(15,226)
Interest and other expense	(10,048)	(8,838)
Interest and other income	1,082	1,098
Loss on commodity derivative contracts	(1,797)	(1,852)
Foreign exchange gain (loss)	(10,292)	(1,861)
Income (loss) before income taxes	4,458	(18,446)
Income tax expense	(9,674)	(5,429)
Net loss	(5,216)	(23,875)
Total assets	132,600	160,650
Capital expenditures	23,517	15,854
Transportation Costs [Member]
Segment Reporting Information [Line Items]
Cost of goods and services sold	4,665
Cost of Purchased Natural Gas [Member]
Segment Reporting Information [Line Items]
Cost of goods and services sold		568
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Production		36
General and administrative	9,222	6,739
Depreciation, depletion and amortization	142	188
Total costs and expenses	9,364	6,963
Operating income	(9,364)	(6,963)
Loss on sale of TBNG		(15,226)
Interest and other expense	(7,026)	(7,794)
Interest and other income	184	250
Foreign exchange gain (loss)	(351)	365
Income (loss) before income taxes	(16,557)	(29,368)
Net loss	(16,557)	(29,368)
Total assets	8,358	61,167
Operating Segments [Member] | Turkey [Member]
Segment Reporting Information [Line Items]
Total revenues	70,789	56,639
Production	10,649	12,136
Exploration, abandonment and impairment	401	934
Seismic and other exploration	488	4,723
General and administrative	5,344	5,729
Depreciation, depletion and amortization	13,917	16,737
Accretion of asset retirement obligations	151	169
Total costs and expenses	35,615	40,996
Operating income	35,174	15,643
Interest and other expense	(3,022)	(1,044)
Interest and other income	897	847
Loss on commodity derivative contracts	(1,797)	(1,852)
Foreign exchange gain (loss)	(9,932)	(2,239)
Income (loss) before income taxes	21,320	11,355
Income tax expense	(9,674)	(5,429)
Net loss	11,646	5,926
Total assets	122,325	109,699
Capital expenditures	23,517	15,854
Operating Segments [Member] | Turkey [Member] | Transportation Costs [Member]
Segment Reporting Information [Line Items]
Cost of goods and services sold	4,665
Operating Segments [Member] | Turkey [Member] | Cost of Purchased Natural Gas [Member]
Segment Reporting Information [Line Items]
Cost of goods and services sold		568
Operating Segments [Member] | Bulgaria [Member]
Segment Reporting Information [Line Items]
Production	120	77
Seismic and other exploration	1
General and administrative	153	349
Accretion of asset retirement obligations	23	21
Total costs and expenses	297	447
Operating income	(297)	(447)
Interest and other income	1	1
Foreign exchange gain (loss)	(9)	13
Income (loss) before income taxes	(305)	(433)
Net loss	(305)	(433)
Total assets	$ 1,917	$ (10,216)

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) ₺ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)Institution	Dec. 31, 2018TRY (₺)	Dec. 31, 2017USD ($)	Dec. 31, 2017TRY (₺)
Financial Statement Line Items With Differences In Reported Amount And Reporting Currency Denominated Amounts [Line Items]
Currency risk descriptions	We have underlying foreign currency exchange rate exposure. Our currency exposures primarily relate to transactions denominated in the Bulgarian Lev, European Union Euro, and TRY. We are also subject to foreign currency exposures resulting from translating the functional currency of our subsidiary financial statements into the U.S. Dollar reporting currency. We have not used foreign currency forward contracts to manage exchange rate fluctuations. At December 31, 2018 and 2017, we had 7.8 million TRY and $4.0 million TRY, respectively (approximately $1.5 million and $1.1 million, respectively) in cash and cash equivalents, which exposes us to exchange rate risk based on fluctuations in the value of the TRY.
Allowance for doubtful accounts	$ 500,000		$ 500,000
Number of financial institutions | Institution	3
TUPRAS [Member]
Financial Statement Line Items With Differences In Reported Amount And Reporting Currency Denominated Amounts [Line Items]
Allowance for doubtful accounts	$ 0
Cash and cash equivalents [Member]
Financial Statement Line Items With Differences In Reported Amount And Reporting Currency Denominated Amounts [Line Items]
Cash and cash equivalents	$ 1,500,000	₺ 7.8	$ 1,100,000	₺ 4

Financial Instruments - Valuati

Financial Instruments - Valuation of Financial Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets (liabilities), fair value	$ (20,130)	$ (26,694)
Measured on a recurring basis [Member] | Derivative Financial Instruments (commodity) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities, fair value		(2,215)
Disclosed but not carried at fair value [Member] | 2017 Term Loan [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities, fair value	(11,938)	(16,613)
Disclosed but not carried at fair value [Member] | 2018 Term Loan [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities, fair value	(8,192)
Disclosed but not carried at fair value [Member] | 2016 Term Loan [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities, fair value		(7,866)
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets (liabilities), fair value		(2,215)
Significant Other Observable Inputs (Level 2) [Member] | Measured on a recurring basis [Member] | Derivative Financial Instruments (commodity) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities, fair value		(2,215)
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets (liabilities), fair value	(20,130)	(24,479)
Significant Unobservable Inputs (Level 3) [Member] | Disclosed but not carried at fair value [Member] | 2017 Term Loan [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities, fair value	(11,938)	(16,613)
Significant Unobservable Inputs (Level 3) [Member] | Disclosed but not carried at fair value [Member] | 2018 Term Loan [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities, fair value	$ (8,192)
Significant Unobservable Inputs (Level 3) [Member] | Disclosed but not carried at fair value [Member] | 2016 Term Loan [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities, fair value		$ (7,866)

Commitments - Aggregate Annual

Commitments - Aggregate Annual Commitments Other Than Debt (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Other Commitments [Line Items]
Total	$ 41,873
2019	7,289
2020	6,236
2021	6,162
2022	6,152
2023	5,842
Thereafter	10,192
Series A Preferred Shares Dividends [Member]
Other Commitments [Line Items]
Total	37,822	[1]
2019	5,526	[1]
2020	5,526	[1]
2021	5,526	[1]
2022	5,526	[1]
2023	5,526	[1]
Thereafter	10,192	[1]
Interest [Member]
Other Commitments [Line Items]
Total	800
2019	800
Leases [Member]
Other Commitments [Line Items]
Total	3,251
2019	963
2020	710
2021	636
2022	626
2023	$ 316
[1]	Dividends on the Series A Preferred Shares may be paid by us, in our sole discretion, in cash at a rate of 12% per annum or in common shares at a rate of 16% per annum or in a combination of cash and common shares. The amounts in the table assume that we pay all future dividend payments solely in cash.

Commitments - Aggregate Annua_2

Commitments - Aggregate Annual Commitments Other Than Debt (Parenthetical) (Detail) - Series A Preferred Shares [Member]	Dec. 31, 2018
Other Commitments [Line Items]
Cash dividend rate, percentage	12.00%
Common share dividend rate, percentage	16.00%

Commitments - Additional Inform

Commitments - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Normal operations purchase arrangements, notice period	30 days
Rent expense	$ 1.3	$ 1.2

Contingencies - Additional Info

Contingencies - Additional Information (Detail) - USD ($)	1 Months Ended		12 Months Ended
	Oct. 31, 2015	Feb. 28, 2013	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2012	Sep. 30, 2016
Loss Contingencies [Line Items]
General and administrative			$ 14,719,000	$ 12,817,000
Morocco [Member] | Government [Member]
Loss Contingencies [Line Items]
Recovery of contractual obligations					$ 5,500,000
Bank guarantee		$ 1,000,000
Accrued liabilities relating to our Tselfat exploration permit					5,000,000
Reversed amount in contingent liabilities previously classified as liabilities held for sale						$ 6,000,000
Bulgaria [Member]
Loss Contingencies [Line Items]
Recovery of contractual obligations					2,000,000
Liquidated damages, claim amount	$ 200,000
Bulgaria [Member] | Aglen Exploration Permit Work Program [Member]
Loss Contingencies [Line Items]
General and administrative					$ 2,000,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail)

Dec. 31, 2018USD ($)Installmentshares

Oct. 02, 2017shares

Mar. 31, 2017USD ($)shares

Nov. 04, 2016USD ($)shares

Jun. 30, 2016shares

Apr. 19, 2016USD ($)

Aug. 13, 2015$ / sharesshares

Apr. 24, 2015$ / sharesshares

Dec. 31, 2014$ / sharesshares

Sep. 30, 2017USD ($)

Jun. 30, 2017USD ($)

Mar. 31, 2017USD ($)shares

Dec. 31, 2016USD ($)

Dec. 31, 2018USD ($)Installmentshares

Dec. 31, 2017USD ($)

Dec. 31, 2014$ / sharesshares

Jun. 14, 2018ft²

Aug. 31, 2016USD ($)

Dec. 30, 2015USD ($)

Jun. 13, 2012USD ($)

Related Party Transaction [Line Items]

Common share purchase warrants issued

233,333

233,333

233,334

Common share purchase

1

1

Common share purchase warrants, exercise price | $ / shares

$ 2.99

$ 5.65

$ 5.99

$ 5.99

Common share purchase warrants issued, expiration period

Jan. 6, 2018

Note receivable - related party | $

$ 6,726,000

$ 11,500,000

Capital and operating expenditures | $

$ 10,600,000

9,300,000

Dalea [Member] | Viking Drilling [Member]

Related Party Transaction [Line Items]

Percentage of ownership interest owned by related party

100.00%

100.00%

Mitchell, and his Children [Member]

Related Party Transaction [Line Items]

Common share purchase warrants issued

23,333

23,333

23,333

Mr. Mitchell [Member]

Related Party Transaction [Line Items]

Common share purchase warrants issued

134,168

134,168

134,169

Randy Rochman [Member]

Related Party Transaction [Line Items]

Preferred shares, issued

15,000

15,000

Jonathon Fite [Member]

Related Party Transaction [Line Items]

Preferred shares, issued

69,000

69,000

Related Party [Member]

Related Party Transaction [Line Items]

Preferred shares, issued

84,000

84,000

Proceeds from issuance of preferred stocks | $

$ 4,200,000

Joint Venture [Member] | Dalea and Funds [Member]

Related Party Transaction [Line Items]

Convertible preferred shares issued upon conversion

40,000

Joint Venture [Member] | Dalea and Funds [Member] | Promissory Note [Member]

Related Party Transaction [Line Items]

Note receivable - related party | $

$ 7,964,053

Cancellation of purchase price in promissory note | $

$ 3,500,000

Debt instrument, maturity date

Jun. 13, 2019

Debt instrument interest rate stated percentage

3.00%

Promissory note, collateral amount | $

$ 2,000,000

Dalea Promissory Note [Member]

Related Party Transaction [Line Items]

Promissory notes default remedy period

30 days

Dalea Promissory Note [Member] | PSIL [Member]

Related Party Transaction [Line Items]

Noncontrolling equity voting interest percentage

50.00%

Gundem Fee Agreement [Member] | Gundem Real Estate [Member]

Related Party Transaction [Line Items]

Debt instrument interest rate stated percentage

5.00%

Promissory note, collateral amount | $

$ 10,000,000

Gundem Fee Agreement [Member] | Muratli Real Estate [Member]

Related Party Transaction [Line Items]

Debt instrument interest rate stated percentage

5.00%

Promissory note, collateral amount | $

$ 5,000,000

Diyarbakir Fee Agreement [Member] | Diyarbakir Real Estate [Member]

Related Party Transaction [Line Items]

Debt instrument interest rate stated percentage

5.00%

Promissory note, collateral amount | $

$ 5,000,000

Gundem Fee Agreement and the Diyarbakir Fee Agreement [Member]

Related Party Transaction [Line Items]

Decrease in principal amount of Amended Note | $

$ 600,000

600,000

Mitchell and his wife [Member] | Riata Management [Member]

Related Party Transaction [Line Items]

Percentage of ownership interest owned by related party

100.00%

100.00%

Mitchell and Family [Member] | Longfellow [Member]

Related Party Transaction [Line Items]

Percentage of ownership interest owned by related party

100.00%

100.00%

MedOil Supply, LLC [Member] | Riata Management [Member]

Related Party Transaction [Line Items]

Percentage of ownership interest owned by related party

100.00%

100.00%

Viking International Master Service Agreement [Member]

Related Party Transaction [Line Items]

Service agreement term

5 years

Service agreement automatic extension term

1 year

Amendment renewal term description

On February 28, 2019, TEMI and PSI entered into an amendment (the “PSI MSA Amendment”) to the PSI MSA, pursuant to which PSI and TEMI agreed to extend the primary term of the PSI MSA to February 26, 2021, with automatic successive renewal terms of one (1) year each, unless terminated by PSI or TEMI by written notice at least sixty (60) days prior to the end of the primary term or any successive renewal term

Longfellow [Member] | TransAtlantic USA [Member]

Related Party Transaction [Line Items]

Office sub lease space | ft²

10,000

Office sub lease commencement date

Jun. 14, 2018

Office sub Lease Expiration Date

Jun. 30, 2020

Office sub lease monthly rent payable during first twelve months | $

$ 18,333.33

$ 18,333.33

Increase in office sub lease monthly rent payable from first year | $

416.67

$ 416.67

Increase in office sub lease monthly rent payable, commencement date

Jun. 30, 2019

Increase in office sub lease monthly rent payable, expiration date

Jun. 30, 2021

Private Placement [Member]

Related Party Transaction [Line Items]

Issuance of common shares

5,773,305

Private Placement [Member] | Cash [Member] | Dalea and Funds [Member]

Related Party Transaction [Line Items]

Issuance of common shares

814,627

2017 Notes [Member] | Dalea and Funds [Member]

Related Party Transaction [Line Items]

Payment of common shares

201,459

Interest receivable | $

$ 5,800,000

$ 5,800,000

$ 6,700,000

2017 Notes [Member] | Private Placement [Member] | Dalea and Funds [Member]

Related Party Transaction [Line Items]

Issuance of common shares

1,974,452

ANBE Note [Member]

Related Party Transaction [Line Items]

Issuance of common shares

355,826

Number of installments | Installment

4

4

Repayments of notes Payable | $

$ 900,000

$ 900,000

$ 900,000

$ 900,000

ANBE Note [Member] | TransAtlantic USA [Member] | Convertible Promissory Note [Member]

Related Party Transaction [Line Items]

Debt instrument interest rate stated percentage

13.00%

Line Of Credit Facility Maximum Borrowing Capacity | $

$ 5,000,000

Line of credit facility borrowing capacity | $

$ 3,600,000

ANBE Note [Member] | Private Placement [Member]

Related Party Transaction [Line Items]

Issuance of common shares

355,826

Series A Preferred Shares [Member]

Related Party Transaction [Line Items]

Preferred shares, issued

921,000

Convertible preferred shares issued upon conversion

45.754

Aggregate number of common shares issued to preferred share holders as payment of dividend

1,808,001

2,591,384

1,808,001

Series A Preferred Shares [Member] | Dalea [Member]

Related Party Transaction [Line Items]

Aggregate number of common shares issued to preferred share holders as payment of dividend

971,724

1,392,768

Series A Preferred Shares [Member] | Related Party [Member]

Related Party Transaction [Line Items]

Preferred shares, issued

495,000

495,000

Series A Preferred Shares [Member] | 2017 Notes [Member] | Private Placement Exchange Offer [Member]

Related Party Transaction [Line Items]

Preferred shares, issued

815,000

Amount of notes exchanged | $

$ 40,750,000

Convertible preferred shares issued upon conversion

20

Value of principal amount on conversion | $

$ 1,000,000

Series A Preferred Shares [Member] | 2017 Notes [Member] | Private Placement Exchange Offer [Member] | Pinon Foundation [Member]

Related Party Transaction [Line Items]

Preferred shares, issued

200,000

Amount of notes exchanged | $

$ 10,000,000

Series A Preferred Shares [Member] | 2017 Notes [Member] | Private Placement Exchange Offer [Member] | Dalea [Member]

Related Party Transaction [Line Items]

Preferred shares, issued

41,000

Amount of notes exchanged | $

$ 2,100,000

Series A Preferred Shares [Member] | 2017 Notes [Member] | Private Placement Exchange Offer [Member] | Mitchell, and his Children [Member]

Related Party Transaction [Line Items]

Preferred shares, issued

40,000

Amount of notes exchanged | $

$ 2,000,000

Series A Preferred Shares [Member] | 2017 Notes [Member] | Private Placement [Member] | Pinon Foundation [Member]

Related Party Transaction [Line Items]

Preferred shares, issued

5,000

Proceeds from issuance of preferred stocks | $

$ 250,000

Series A Preferred Shares [Member] | 2017 Notes [Member] | Private Placement [Member] | Mitchell, and his Children [Member]

Related Party Transaction [Line Items]

Preferred shares, issued

1,000

Proceeds from issuance of preferred stocks | $

$ 50,000

Series A Preferred Shares [Member] | 2017 Notes [Member] | Private Placement [Member] | Certain Holders [Member]

Related Party Transaction [Line Items]

Preferred shares, issued

106,000

Proceeds from issuance of preferred stocks | $

$ 5,300,000

Related Party Transactions - Re

Related Party Transactions - Related Party Accounts Receivable and Accounts Payable (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Total related party accounts receivable	$ 878	$ 1,023
Total related party accounts payable	2,922	3,141
Riata Management Service Agreement [Member]
Related Party Transaction [Line Items]
Total related party accounts receivable	526	576
Total related party accounts payable	372	341
PSI MSA [Member]
Related Party Transaction [Line Items]
Total related party accounts receivable	352	447
Total related party accounts payable	2,439	2,119
Board of Directors [Member]
Related Party Transaction [Line Items]
Total related party accounts payable	$ 111
Interest payable on Series A Preferred Shares [Member]
Related Party Transaction [Line Items]
Total related party accounts payable		$ 681

Divestitures and Discontinued_3

Divestitures and Discontinued Operations - Additional Information (Detail) - USD ($)	Apr. 10, 2017	Feb. 24, 2017	Dec. 31, 2017	Aug. 09, 2017	Sep. 01, 2016
Discontinued Operations And Disposal Groups [Line Items]
Purchase price reduction amount		$ 200,000
Proceeds from escrow funds	$ 2,900,000
Loss on sale of TBNG			$ 15,200,000
Delvina Gas Company Ltd [Member]
Discontinued Operations And Disposal Groups [Line Items]
Percentage of outstanding shares transferred				25.00%
Payment receivable in exchange for transfer of outstanding shares				$ 300,000
Albania [Member] | Delvina Gas Company Ltd [Member]
Discontinued Operations And Disposal Groups [Line Items]
Percentage of outstanding shares transferred					75.00%
Payment receivable in exchange for transfer of outstanding shares					$ 12,000,000
Thrace Basin Natural Gas (Turkiye) Corporation [Member]
Discontinued Operations And Disposal Groups [Line Items]
Gross proceeds on sale of ownership interests		20,700,000
Net cash proceeds on sale of ownership interests		16,100,000
Escrow deposit		$ 3,100,000

Divestitures and Discontinued_4

Divestitures and Discontinued Operations - Reclassification of Accumulated Foreign Currency Translation Adjustment Realized Into Earnings from Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Discontinued Operations And Disposal Groups [Line Items]
Net loss on sale of TBNG		$ (15,200)
Thrace Basin Natural Gas (Turkiye) Corporation [Member]
Discontinued Operations And Disposal Groups [Line Items]
Total cash proceeds for TBNG	$ 20,707
Less: TBNG net assets	12,869
Gain on sale before accumulated foreign currency translation adjustment	7,838
Less: TBNG accumulated foreign currency translation adjustment	(23,064)
Net loss on sale of TBNG	$ (15,226)

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ in Thousands	Feb. 28, 2019	Feb. 22, 2019	Apr. 19, 2016
Joint Venture [Member] | Dalea and Funds [Member] | Promissory Note [Member]
Subsequent Event [Line Items]
Debt instrument interest rate stated percentage			3.00%
Debt instrument, maturity date			Jun. 13, 2019
Subsequent Event [Member] | Joint Venture [Member] | Dalea and Funds [Member] | Promissory Note [Member]
Subsequent Event [Line Items]
Debt instrument, maturity date	Feb. 26, 2021
Subsequent Event [Member] | PSI MSA [Member]
Subsequent Event [Line Items]
Service agreement automatic extension term	1 year
Amendment Renewal Term Description	On February 28, 2019, TEMI and PSI entered into an amendment (the “PSI MSA Amendment”) to the PSI MSA, pursuant to which PSI and TEMI agreed to extend the primary term of the PSI MSA to February 26, 2021, with automatic successive renewal terms of one year each, unless terminated by PSI or TEMI by written notice at least 60 days prior to the end of the primary term or any successive renewal term
Subsequent Event [Member] | 2019 Term Loan [Member]
Subsequent Event [Line Items]
Debt instrument interest rate stated percentage		7.50%
Debt instrument interest rate basis for effective rate		The 2019 Term Loan bears interest at a fixed rate of 7.5% (plus 0.375% for Banking and Insurance Transactions Tax per the Turkish government) per annum.
Debt instrument payment terms		The 2019 Term Loan has a ten-month grace period during which the 2019 Term Loan bears interest but no payments are due other than a single interest only payment of $0.76 million in August 2019. After the ten-month grace period, the 2019 Term Loan is payable in fourteen monthly principal installments of $1.43 million plus interest.
Debt instrument, payment grace period		10 months
Line of credit facility, expiration date		Feb. 28, 2021
Subsequent Event [Member] | 2019 Term Loan [Member] | Turkish Banking and Insurance Transactions Tax Rate [Member]
Subsequent Event [Line Items]
Debt instrument basis spread on variable rate		0.375%
Subsequent Event [Member] | 2019 Term Loan [Member] | Single Interest Payment in August 2019 [Member]
Subsequent Event [Line Items]
Amount of interest payable		$ 760
Subsequent Event [Member] | 2019 Term Loan [Member] | Fourteen Monthly Installments [Member]
Subsequent Event [Line Items]
Debt instrument, monthly principal installments		$ 1,430
Subsequent Event [Member] | 2019 Term Loan [Member] | Credit Agreement [Member] | DenizBank [Member]
Subsequent Event [Line Items]
Line of credit facility, initiation date		Feb. 22, 2019
Line Of Credit Facility Maximum Borrowing Capacity		$ 20,000
Subsequent Event [Member] | 2019 Term Loan [Member] | Line of Credit [Member] | Mr. Mitchell [Member]
Subsequent Event [Line Items]
Line of credit facility ownership percentage		80.00%
Subsequent Event [Member] | 2019 Term Loan [Member] | Line of Credit [Member] | Mr. Uras [Member]
Subsequent Event [Line Items]
Line of credit facility ownership percentage		20.00%
Subsequent Event [Member] | 2019 Term Loan [Member] | Line of Credit [Member] | Mr. Uras [Member] | Ankara Real Estate [Member]
Subsequent Event [Line Items]
Line of credit facility ownership percentage		100.00%