Gran Tierra Energy (GTE) 10-Q 3 Nov 20 2020 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Oct. 30, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-34018
Entity Registrant Name	GRAN TIERRA ENERGY INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	98-0479924
Entity Address, Address Line One	900, 520 - 3 Avenue SW
Entity Address, City or Town	Calgary,
Entity Address, State or Province	AB
Entity Address, Country	CA
Entity Address, Postal Zip Code	T2P 0R3
City Area Code	403
Local Phone Number	265-3221
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	GTE
Security Exchange Name	NYSEAMER
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		366,981,556
Entity Central Index Key	0001273441
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
OIL SALES (Note 7)	$ 53,142,000	$ 132,491,000	$ 173,045,000	$ 443,049,000
EXPENSES
Operating	19,645,000	35,603,000	69,933,000	104,119,000
Workover	1,076,000	10,979,000	14,740,000	30,025,000
Transportation	1,286,000	3,179,000	8,549,000	16,167,000
COVID-19 related costs (Note 8)	1,108,000	0	1,529,000	0
Depletion, depreciation and accretion	31,340,000	49,812,000	131,118,000	164,430,000
Goodwill impairment (Note 4)	0	0	102,581,000	0
Asset impairment (Note 4)	104,731,000	0	507,093,000	0
General and administrative	4,562,000	7,637,000	16,476,000	25,874,000
Severance	122,000	140,000	1,469,000	1,082,000
Foreign exchange loss	4,275,000	6,840,000	20,094,000	5,581,000
Financial instruments (gain) loss (Note 11)	(713,000)	12,285,000	51,869,000	(2,890,000)
Other loss	67,000	11,305,000	67,000	11,305,000
Interest expense (Note 5)	14,029,000	12,153,000	40,204,000	30,655,000
EXPENSES	181,528,000	149,933,000	965,722,000	386,348,000
INTEREST INCOME	0	130,000	345,000	660,000
(LOSS) INCOME BEFORE INCOME TAXES	(128,386,000)	(17,312,000)	(792,332,000)	57,361,000
INCOME TAX EXPENSE (RECOVERY)
Current (Note 9)	637,000	3,049,000	560,000	13,923,000
Deferred (Note 9)	(21,202,000)	8,472,000	(62,796,000)	31,752,000
INCOME TAX EXPENSE (RECOVERY)	(20,565,000)	11,521,000	(62,236,000)	45,675,000
NET AND COMPREHENSIVE (LOSS) INCOME	$ (107,821,000)	$ (28,833,000)	$ (730,096,000)	$ 11,686,000
NET (LOSS) INCOME PER SHARE
Basic and Diluted (in dollars per share)	$ (0.29)	$ (0.08)	$ (1.99)	$ 0.03
WEIGHTED AVERAGE SHARES OUTSTANDING - BASIC (Note 6) (in shares)	366,981,556	372,195,176	366,981,556	379,701,405
WEIGHTED AVERAGE SHARES OUTSTANDING - DILUTED (Note 6) (in shares)	366,981,556	372,195,176	366,981,556	379,701,664

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current Assets
Cash and cash equivalents (Note 12)	$ 21,385	$ 8,301
Restricted cash and cash equivalents (Note 12)	423	516
Accounts receivable	4,502	36,291
Investment (Note 11)	33,209	94,741
Taxes receivable	48,166	135,838
Other current assets	14,289	15,001
Total Current Assets	121,974	290,688
Oil and Gas Properties
Proved	715,772	1,258,934
Unproved	285,276	310,809
Total Oil and Gas Properties	1,001,048	1,569,743
Other capital assets	6,303	7,650
Total Property, Plant and Equipment (Note 3)	1,007,351	1,577,393
Other Long-Term Assets
Deferred tax assets	40,600	44,003
Taxes receivable	38,479	25,869
Restricted cash and cash equivalents (Note 12)	3,007	2,258
Other	16	1,872
Goodwill (Note 4)	0	102,581
Total Other Long-Term Assets	82,102	176,583
Total Assets	1,211,427	2,044,664
Current Liabilities
Accounts payable and accrued liabilities	68,408	195,513
Derivatives (Note 11)	3,184	775
Equity compensation award liability (Note 6 and 11)	471	3,053
Total Current Liabilities	72,063	199,341
Long-Term Liabilities
Long-term debt (Notes 5 and 11)	784,311	700,459
Deferred tax liabilities	0	59,762
Asset retirement obligation	45,585	43,419
Equity compensation award liability (Note 6 and 11)	1,860	4,806
Other long-term liabilities	3,316	4,267
Total Long-Term Liabilities	835,072	812,713
Contingencies (Note 10)
Shareholders’ Equity
Common Stock (Note 6) (366,981,556 and 366,981,556 shares issued and outstanding of Common Stock, par value $0.001 per share, as at September 30, 2020, and December 31, 2019, respectively)	10,270	10,270
Additional paid-in capital	1,284,405	1,282,627
Deficit	(990,383)	(260,287)
Total Shareholders’ Equity	304,292	1,032,610
Total Liabilities and Shareholders’ Equity	$ 1,211,427	$ 2,044,664

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Common Stock, shares issued (in shares)	366,981,556	366,981,556
Common Stock, shares outstanding (in shares)	366,981,556	366,981,556
Common Stock, par value (in dollars per share)	$ 0.001	$ 0.001

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating Activities
Net (loss) income	$ (730,096,000)	$ 11,686,000
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depletion, depreciation and accretion	131,118,000	164,430,000
Goodwill impairment (Note 4)	102,581,000	0
Asset impairment (Note 4)	507,093,000	0
Deferred tax (recovery) expense	(62,796,000)	31,752,000
Stock-based compensation (recovery) expense (Note 6)	(707,000)	1,092,000
Amortization of debt issuance costs (Note 5)	2,774,000	2,574,000
Unrealized foreign exchange loss	22,335,000	5,303,000
Financial instruments loss (gain) (Note 11)	51,869,000	(2,890,000)
Cash settlement of financial instruments	9,970,000	(2,275,000)
Other non-cash loss	2,026,000	11,305,000
Cash settlement of asset retirement obligation	(199,000)	(707,000)
Non-cash lease expenses	1,494,000	1,366,000
Lease payments	(1,404,000)	(1,603,000)
Net change in assets and liabilities from operating activities (Note 12)	23,288,000	(83,606,000)
Net cash provided by operating activities	59,346,000	138,427,000
Investing Activities
Additions to property, plant and equipment	(56,378,000)	(310,579,000)
Property acquisitions, net of cash acquired	0	(77,772,000)
Changes in non-cash investing working capital	(69,549,000)	20,138,000
Net cash used in investing activities (Note 12)	(125,927,000)	(368,213,000)
Financing Activities
Proceeds from bank debt, net of issuance costs (Note 5)	88,382,000	246,000,000
Repayment of bank debt (Note 5)	(7,000,000)	(189,000,000)
Repurchase of convertible notes	0	(115,000,000)
Repurchase of shares of Common Stock	0	(37,560,000)
Lease payments	(307,000)	0
Proceeds from issuance of Senior Notes, net of issuance costs	0	289,298,000
Net cash provided by financing activities	81,075,000	193,738,000
Foreign exchange loss on cash, cash equivalents and restricted cash and cash equivalents	(754,000)	(1,506,000)
Net increase (decrease) in cash, cash equivalents and restricted cash and cash equivalents	13,740,000	(37,554,000)
Cash, cash equivalents and restricted cash and cash equivalents, beginning of period (Note 12)	11,075,000	54,308,000
Cash, cash equivalents and restricted cash and cash equivalents, end of period (Note 12)	$ 24,815,000	$ 16,754,000

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Share Capital	Additional Paid-in Capital	Deficit	DeficitCumulative adjustment for accounting change related to leases
Balance, beginning of period at Dec. 31, 2018		$ 10,290	$ 1,318,048	$ (298,588)	$ (390)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation (Note 6)			1,566
Repurchase and cancellation of Common Stock		(20)	(37,540)
Net (loss) income	$ 11,686			11,686
Balance, end of period at Sep. 30, 2019	1,005,052	10,270	1,282,074	(287,292)
Balance, beginning of period at Jun. 30, 2019		10,285	1,295,106	(258,459)	0
Increase (Decrease) in Stockholders' Equity
Stock-based compensation (Note 6)			563
Repurchase and cancellation of Common Stock		(15)	(13,595)
Net (loss) income	(28,833)			(28,833)
Balance, end of period at Sep. 30, 2019	1,005,052	10,270	1,282,074	(287,292)
Balance, beginning of period at Dec. 31, 2019		10,270	1,282,627	(260,287)	0
Increase (Decrease) in Stockholders' Equity
Stock-based compensation (Note 6)			1,778
Repurchase and cancellation of Common Stock		0	0
Net (loss) income	(730,096)			(730,096)
Balance, end of period at Sep. 30, 2020	304,292	10,270	1,284,405	(990,383)
Balance, beginning of period at Jun. 30, 2020		10,270	1,283,798	(882,562)	$ 0
Increase (Decrease) in Stockholders' Equity
Stock-based compensation (Note 6)			607
Repurchase and cancellation of Common Stock		0	0
Net (loss) income	(107,821)			(107,821)
Balance, end of period at Sep. 30, 2020	$ 304,292	$ 10,270	$ 1,284,405	$ (990,383)

Description of Business

Description of Business	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business Gran Tierra Energy Inc., a Delaware corporation (the “Company” or “Gran Tierra”), is a publicly traded company focused on oil and natural gas exploration and production in Colombia and Ecuador.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies These interim unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”). The information furnished herein reflects all normal recurring adjustments that are, in the opinion of management, necessary for the fair presentation of results for the interim periods. The note disclosure requirements of annual consolidated financial statements provide additional disclosures to that required for interim unaudited condensed consolidated financial statements. Accordingly, these interim unaudited condensed consolidated financial statements should be read in conjunction with the Company’s consolidated financial statements as at and for the year ended December 31, 2019, included in the Company’s 2019 Annual Report on Form 10-K. The Company’s significant accounting policies are described in Note 2 of the consolidated financial statements which are included in the Company’s 2019 Annual Report on Form 10-K and are the same policies followed in these interim unaudited condensed consolidated financial statements, except as noted below. The Company has evaluated all subsequent events through to the date these interim unaudited condensed consolidated financial statements were issued. Recently Adopted Accounting Pronouncements Financial Instruments - Credit Losses (ASC 326) In June 2016, the FASB issued ASU 2016-13, "Financial Instruments - Credit Losses". This ASU replaces the incurred loss impairment methodology with a methodology that reflects expected credit losses and requires a broader range of reasonable and supportable information to support credit loss estimates. In December 2019, the FASB issued ASU 2019-10, "Financial Instruments - Credit Losses, Derivatives and Hedging and Leases", which is codification improvement of ASU 2016-13. The Company adopted this ASU on January 1, 2020, the adoption of which had no impact on the Company. At each reporting date, the Company assesses the expected lifetime credit losses on initial recognition of trade accounts receivable. Credit risk is assessed based on the number of days the receivable has been outstanding and the internal credit assessment of the customer. The expected loss rates are based on payment profiles over a period of 36 months prior to the period-end and the corresponding historical credit losses experienced within this period. Historical loss rates are adjusted to reflect current and forward looking economic factors of the country where the Company sells oil that affect the ability of the customers to settle the receivables. Trade receivables are written off when there is no reasonable expectation of recovery. Risks and Measurement Uncertainty In March 2020, the outbreak of the COVID-19 virus, which was declared a pandemic by the World Health Organization, has spread across the globe and impacted worldwide economic activity. In addition, global commodity prices declined significantly due to disputes between major oil producing countries combined with the impact of the COVID-19 pandemic and associated reductions in global demand for oil. Governments worldwide, including those in Colombia and Ecuador, the countries where the Company operates, enacted emergency measures to combat the spread of the virus. These measures, which include the implementation of travel bans, self-imposed quarantine periods and physical distancing, caused material disruption to businesses globally resulting in an economic slowdown. Governments and central banks have reacted with significant monetary and fiscal interventions designed to stabilize economic conditions; however, the success of these interventions is not currently determinable. The current challenging economic climate is having and may continue to have significant adverse impacts on the Company including, but not exclusively: • material declines in revenue and cash flows as a result of the decline in commodity prices; • declines in revenue and operating activities due to reduced capital programs and the shut-in of production; • impairment charges (see Note 4); • inability to comply with covenants and restrictions in debt agreements; • inability to access financing sources; • increased risk of non-performance by the Company’s customers and suppliers; • interruptions in operations as the Company adjusts personnel to the dynamic environment; and • inability to operate or delay in operations as a result COVID-19 restrictions in the countries in which the Company operates. The unprecedented decline in oil prices has materially reduced the Company’s forecasted EBITDAX and the estimated value of its oil reserves. Based on current forecasted Brent pricing and production levels, which can change materially in very short time frames, the Company is forecasted to be in compliance with the amended financial covenants contained in the Company's Senior Secured Credit Facility (the "revolving credit facility") for at least the next year from the date of these financial statements. The amount available under the Company’s senior secured credit facility is based on the lenders determination of the borrowing base. The borrowing base is determined, by the lenders, based on the Company’s reserves and commodity prices. The next renewal of the borrowing base is scheduled for November 2020 and there is risk that the borrowing base may be reduced by the lenders. In addition, the Company’s ability to borrow under the credit facility may be limited by the terms of the indentures for the 6.25% Senior Notes and 7.75% Senior Notes. The risk of non-compliance with the covenants in the lending agreements and the risk associated with maintaining the borrowing base is heightened in the current period of volatility coupled with the unprecedented disruption caused by the COVID-19 pandemic. Management currently expects that the Company will continue to meet the terms of the credit facility or obtain further amendments or waivers if and when required. The Company also expects to be able to maintain the borrowing base at a level in excess of the amount borrowed. However, there can be no assurances that the Company’s liquidity can be maintained at or above current levels during this period of volatility and global economic uncertainty. The situation is dynamic and the ultimate duration and magnitude of the impact on the economy and the financial effect on the Company is not known at this time. Estimates and judgments made by management in the preparation of the financial statements are increasingly difficult and subject to a higher degree of measurement uncertainty during this volatile period. In the near term, matters in these financial statements that are most subject to be impacted by this volatile period are the Company's assessment of liquidity and access to capital, the carrying value of long-lived assets and the valuation of the deferred tax assets.

Property, Plant and Equipment

Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment (Thousands of U.S. Dollars) As at September 30, 2020 As at December 31, 2019 Oil and natural gas properties Proved $ 3,937,361 $ 3,850,565 Unproved 285,276 310,809 4,222,637 4,161,374 Other (1) 32,297 26,287 4,254,934 4,187,661 Accumulated depletion and depreciation and impairment (3,247,583) (2,610,268) $ 1,007,351 $ 1,577,393 (1) Included in other are right-of-use assets for operating and finance leases, net book value of which was $5.1 million as at September 30, 2020 ($5.7 million as at December 31, 2019).

Impairment

Impairment	9 Months Ended
	Sep. 30, 2020
Impairment Disclosure [Abstract]
Impairment	Impairment Asset Impairment (i) Oil and gas property impairment For the three and nine months ended September 30, 2020, Gran Tierra recorded ceiling test impairment losses of $104.7 and $502.9 million, respectively, as a result of lower oil prices. The Company follows the full cost method of accounting for its oil and gas properties. Under this method, the net book value of properties on a country-by-country basis, less related deferred income taxes, may not exceed a calculated “ceiling”. The ceiling is the estimated after-tax future net revenues from proved oil and gas properties, discounted at 10% per year. In calculating discounted future net revenues, oil and natural gas prices are determined using the average price for the 12-month period prior to the ending date of the period covered by the balance sheet, calculated as an unweighted arithmetic average of the first-day-of-the-month price for each month within such period. That average price is then held constant, except for changes which are fixed and determinable by existing contracts. Therefore, ceiling test estimates are based on historical prices discounted at 10% per year and it should not be assumed that estimates of future net revenues represent the fair market value of the Company's reserves. In accordance with GAAP, Gran Tierra used an average Brent price of $47.95 per bbl for the purposes of the September 30, 2020 ceiling test calculations (September 30, 2019 - $67.20). There was no ceiling test impairment for the three and nine months ended September 30, 2019. (ii) Inventory Impairment For the three and nine months ended September 30, 2020, the Company recorded $0.1 and $4.2 million, respectively, relating to the impairment of oil inventory due to the decline in commodity pricing. There was no inventory impairment for the three and nine months ended September 30, 2019. Goodwill Impairment For the three and nine months ended September 30, 2020, the Company recorded nil and $102.6 million, respectively, of goodwill impairment relating to its Colombia business unit. The impairment was due to the carrying value of the unit exceeding its fair value as a result of the impact of lower forecasted commodity prices. The estimated fair value of the Colombia business unit for the goodwill impairment test was based on the discounted after-tax cash flows associated with the proved and probable reserves of the reporting unit. There was no goodwill impairment for the three and nine months ended September 30, 2019.

Debt and Debt Issuance Costs

Debt and Debt Issuance Costs	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Debt and Debt Issuance Costs	Debt and Debt Issuance Costs The Company's debt at September 30, 2020 and December 31, 2019 was as follows: (Thousands of U.S. Dollars) As at September 30, 2020 As at December 31, 2019 6.25% Senior Notes $ 300,000 $ 300,000 7.75% Senior Notes 300,000 300,000 Revolving credit facility 200,000 118,000 Unamortized debt issuance costs (18,925) (21,081) Long-term debt 781,075 696,919 Long-term lease obligation (1) 3,236 3,540 $ 784,311 $ 700,459 (1) The current portion of the lease obligation has been included in accounts payable and accrued liabilities on the Company's balance sheet and totaled $3.3 million as at September 30, 2020 (December 31, 2019 - $3.3 million). On June 1, 2020, the Company completed the semi-annual re-determination of the Company's revolving credit facility resulting in a reduction of the borrowing base from $300 million to $225 million with the next re-determination to occur in November 2020. Management has obtained a relief from compliance with certain financial covenants until October 1, 2021 ("the covenant relief period"), permitting the ratio of total debt to Covenant EBITDAX ("EBITDAX") to be greater than 4.0 to 1.0, Senior Secured Debt to EBITDAX ratio must not exceed 2.5 to 1.0, and EBITDAX to interest expense ratio for the trailing four quarter periods measured as of the last day of the fiscal quarters ending June 30, 2020 and September 30, 2020, must be at least 2.5 to 1.0; as of the last day of the fiscal quarters ending December 31, 2020 and March 31, 2021, must be at least 2.0 to 1.0; and back to at least 2.5 to 1.0 thereafter. The Company is required to comply with various covenants, which as disclosed above, have been modified in response to the current market conditions and the COVID-19 pandemic. As of September 30, 2020, the Company was in compliance with all applicable covenants in the revolving credit facility. In addition to the covenant relief, the amendment to the credit agreement in connection with the semi-annual re-determination also amended the interest rate to either, at the borrower’s option, LIBOR plus a spread ranging from 2.90% to 4.90%, or base rate plus a spread ranging from 1.90% to 3.90%, with such spread in each case dependent upon our Senior Secured Leverage Ratio (as defined in the credit agreement), provided that during the covenant relief period the spread is increased by 125 basis points, (i) provided for a borrowing condition that we shall not have cash and cash equivalents (other than Excluded Cash, as defined in the credit agreement) in excess of $15.0 million, (ii) added certain mandatory prepayments, including for cash balances in excess of $15.0 million and (iii) amended and added certain negative covenants, including, without limitation, certain additional limitations on occurrence of indebtedness, liens and investments, the making of restricted payments, prepayments of indebtedness, and acquisitions and mergers. After the expiration of covenant relief period, the Company must maintain compliance with the following financial covenants: limitations on Company's ratio of debt to EBITDAX to a maximum of 4.0 to 1.0; limitations on Company's ratio of Senior Secured Debt to EBITDAX to a maximum of 3.0 to 1.0; and the maintenance of a ratio of EBITDAX to interest expense of at least 2.5 to 1.0. If the Company fails to comply with these financial covenants, it would result in a default under the terms of the credit agreement, which could result in an acceleration of repayment of all indebtedness under the Company's revolving credit facility. Interest Expense The following table presents total interest expense recognized in the accompanying interim unaudited condensed consolidated statements of operations: Three Months Ended September 30, Nine Months Ended September 30, (Thousands of U.S. Dollars) 2020 2019 2020 2019 Contractual interest and other financing expenses $ 13,191 $ 11,364 $ 37,430 $ 28,081 Amortization of debt issuance costs 838 789 2,774 2,574 $ 14,029 $ 12,153 $ 40,204 $ 30,655

Share Capital

Share Capital	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Share Capital	Share Capital Shares of Common Stock Balance at December 31, 2019 and September 30, 2020 366,981,556 Equity Compensation Awards The following table provides information about p erformance stock units (“PSUs”), deferred share units (“DSUs”), and stock option activity for the nine months ended September 30, 2020: PSUs DSUs Stock Options Number of Outstanding Share Units Number of Outstanding Share Units Number of Outstanding Stock Options Weighted Average Exercise Price/Stock Option ($) Balance, December 31, 2019 11,371,367 1,251,994 10,612,872 2.78 Granted 16,063,219 1,708,720 8,653,255 0.71 Exercised (2,531,995) — — — Forfeited (1,629,187) — (992,287) 2.02 Expired — — (2,847,970) 3.48 Balance, September 30, 2020 23,273,404 2,960,714 15,425,870 1.56 Weighted Average Shares Outstanding Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Weighted average number of common shares outstanding 366,981,556 372,195,176 366,981,556 379,701,405 Shares issuable pursuant to stock options — — — 14,315 Shares assumed to be purchased from proceeds of stock options — — — (14,056) Weighted average number of diluted common shares outstanding 366,981,556 372,195,176 366,981,556 379,701,664 Common shares outstanding, as at period end 366,981,556 366,981,556 366,981,556 366,981,556

Revenue

Revenue	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Revenue	RevenueThe Company's revenues are generated from oil sales at prices which reflect the blended prices received upon shipment by the purchaser at defined sales points or are defined by contract relative to ICE Brent and adjusted for Vasconia or Castilla crude differentials, quality, and transportation discounts each month. For the three and nine months ended September 30, 2020, 100% (three and nine months ended September 30, 2019 - 100%) of the Company's revenue resulted from oil sales. During the three and nine months ended September 30, 2020, quality and transportation discounts were 22% and 27%, respectively, of the average ICE Brent price (three and nine months ended September 30, 2019 - 16% and 15%, respectively). During the three and nine months ended September 30, 2020, the Company's production was sold primarily to two major customers in Colombia (three and nine months ended September 30, 2019 - three).As at September 30, 2020, accounts receivable included nil of accrued sales revenue related to September 2020 production (December 31, 2019 - $0.1 million related to December 31, 2019 production).

COVID-19 Costs

COVID-19 Costs	9 Months Ended
	Sep. 30, 2020
Unusual or Infrequent Items, or Both [Abstract]
COVID-19 Costs	COVID-19 Costs The COVID-19 pandemic resulted in extra operating and transportation costs related to COVID-19 health and safety preventative measures including incremental sanitation requirements and enhanced procedures for trucking barrels and crew changes in the field. Below is a break-down of the costs: Three Months Ended September 30, Nine Months Ended September 30, (Thousands of U.S. Dollars) 2020 2019 2020 2019 Operating expenses $ 1,012 $ — $ 1,433 $ — Transportation costs 96 — 96 — COVID-19 costs $ 1,108 $ — $ 1,529 $ —

Taxes

Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Taxes	Taxes The Company's effective tax rate was 8% for the nine months ended September 30, 2020, compared to 79% in the comparative period of 2019. Current income tax expense was lower in the nine months ended September 30, 2020, compared to the corresponding period in 2019, primarily as a result of lower income in Colombia. The deferred income tax recovery for the nine months ended September 30, 2020, was the result of a ceiling test impairment loss in Colombia; which was partially offset by losses incurred in Colombia that are now fully offset by a valuation allowance. The deferred income tax expense in the comparative period of 2019 was mainly the result of tax depreciation being higher than accounting depreciation in Colombia. For the nine months ended September 30, 2020, the difference between the effective tax rate of 8% and the 32% Colombian tax rate was primarily due to an increase in the valuation allowance, foreign translation adjustments, the non-deductibility of goodwill impairment for tax purposes, and the non-deductible portion (50%) of the unrealized loss on the PetroTal shares.

Contingencies

Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Contingencies Legal Proceedings Gran Tierra has a number of lawsuits and claims pending, including a dispute with the Agencia Nacional de Hidrocarburos (National Hydrocarbons Agency) ("ANH") relating to the calculation of HPR royalties. Discussions with the ANH are ongoing. Although the outcome of these lawsuits and disputes cannot be predicted with certainty, Gran Tierra believes the resolution of these matters would not have a material adverse effect on the Company’s consolidated financial position, results of operations or cash flows. Gran Tierra records costs as they are incurred or become probable and determinable. Letters of credit and other credit support At September 30, 2020, the Company had provided letters of credit and other credit support totaling $96.6 million (December 31, 2019 - $120.6 million) as security relating to work commitment guarantees in Colombia and Ecuador contained in exploration contracts and other capital or operating requirements.

Financial Instruments and Fair

Financial Instruments and Fair Value Measurement	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Financial Instruments and Fair Value Measurement	Financial Instruments and Fair Value Measurement Financial Instruments At September 30, 2020, the Company’s financial instruments recognized on the balance sheet consisted of: cash and cash equivalents, restricted cash and cash equivalents, accounts receivable, investment, accounts payable and accrued liabilities, derivatives, long-term debt, equity compensation award liability and other long-term liabilities. Fair Value Measurement The fair value of investment, derivatives and equity compensation award liability is remeasured at the estimated fair value at the end of each reporting period. Investment in PetroTal The fair value of the Company's investment in PetroTal was estimated to be $33.2 million at September 30, 2020, based on the closing stock price of PetroTal of $0.18 CAD and the foreign exchange rate at that date. PetroTal is a publicly-traded energy company incorporated and domiciled in Canada engaged in exploration, appraisal and development of crude oil and natural gas in Peru. PetroTal's shares are listed on the Toronto Stock Exchange Venture under the trading symbol 'TAL' and on the London Stock Exchange Alternative Investment Market under the trading symbol 'PTAL'. Gran Tierra through a subsidiary holds approximately 246 million common shares representing approximately 30% of PetroTal's issued and outstanding common shares. Gran Tierra has the right to nominate two directors to the board of PetroTal. Commodity and Foreign Currency Derivatives The fair value of commodity price and foreign currency derivatives is estimated based on various factors, including quoted market prices in active markets and quotes from third parties. The Company also performs an internal valuation to ensure the reasonableness of third party quotes. In consideration of counterparty credit risk, the Company assessed the possibility of whether the counterparty to the derivative would default by failing to make any contractually required payments. Additionally, the Company considers that it is of substantial credit quality and has the financial resources and willingness to meet its potential repayment obligations associated with the derivative transactions. PSUs and DSUs The fair value of the PSUs liability was estimated based on a pricing model using inputs such as quoted market prices in an active market, and PSUs performance factor. The fair value of DSUs liability is measured using quoted market prices in an active market. The fair value of investment, derivatives and PSUs and DSUs liability at September 30, 2020, and December 31, 2019, was as follows: (Thousands of U.S. Dollars) As at September 30, 2020 As at December 31, 2019 Investment $ 33,209 $ 94,741 Derivative liability $ 3,184 $ 775 PSUs and DSUs liability 2,327 7,859 $ 5,511 $ 8,634 The following table presents gains or losses on financial instruments recognized in the accompanying interim unaudited condensed consolidated statements of operations: Three Months Ended September 30, Nine Months Ended September 30, (Thousands of U.S. Dollars) 2020 2019 2020 2019 Commodity price derivative (gain) loss $ (2,206) $ (24) $ (12,983) $ 464 Foreign currency derivatives loss 33 337 3,566 392 Investment loss (gain) 1,055 11,972 60,124 (3,746) Financial instruments loss 405 — 1,162 — $ (713) $ 12,285 $ 51,869 $ (2,890) Financial instruments not recorded at fair value include the Company's 6.25% Senior Notes due 2025 (the "6.25% Senior Notes") and 7.75% Senior Notes due 2027 (the "7.75% Senior Notes"). At September 30, 2020, the carrying amounts of the 6.25% Senior Notes and the 7.75% Senior Notes were $291.9 million and $290.6 million, respectively, which represented the aggregate principal amount less unamortized debt issuance costs, and the fair values were $103.6 million and $105.6 million, respectively. The fair value of long-term restricted cash and cash equivalents and the revolving credit facility approximated their carrying value because interest rates are variable and reflective of market rates. The fair values of other financial instruments approximate their carrying amounts due to the short-term maturity of these instruments. GAAP establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. This hierarchy consists of three broad levels. Level 1 inputs consist of quoted prices (unadjusted) in active markets for identical assets and liabilities and have the highest priority. Level 2 and 3 inputs are based on significant other observable inputs and significant unobservable inputs, respectively, and have lower priorities. The Company uses appropriate valuation techniques based on the available inputs to measure the fair values of assets and liabilities. At September 30, 2020, the fair value of the investment and DSUs liability was determined using Level 1 inputs, the fair value of derivatives and PSUs liability was determined using Level 2 inputs. The Company uses available market data and valuation methodologies to estimate the fair value of debt. The fair value of debt is the estimated amount the Company would have to pay a third party to assume the debt, including a credit spread for the difference between the issue rate and the period end market rate. The credit spread is the Company’s default or repayment risk. The credit spread (premium or discount) is determined by comparing the Company’s Senior Notes and revolving credit facility to new issuances (secured and unsecured) and secondary trades of similar size and credit statistics for both public and private debt. The disclosure in the paragraph above regarding the fair value of cash and restricted cash and cash equivalents and Senior Notes was based on Level 1 inputs and the fair value of credit facility was based on Level 2 inputs. The Company’s non-recurring fair value measurements include asset retirement obligations. The fair value of an asset retirement obligation is measured by reference to the expected future cash outflows required to satisfy the retirement obligation discounted at the Company’s credit-adjusted risk-free interest rate. Commodity Price Derivatives The Company utilizes commodity price derivatives to manage the variability in cash flows associated with the forecasted sale of its oil production, reduce commodity price risk and provide a base level of cash flow in order to assure it can execute at least a portion of its capital spending. At September 30, 2020, the Company had outstanding commodity price derivative positions as follows: Period and type of instrument Volume, Reference Sold Put ($/bbl, Weighted Average) Purchased Put ($/bbl, Weighted Average) Sold Call ($/bbl, Weighted Average) Premium ($/bbl, Weighted Average) Collars: October 1, to December 31, 2020 11,000 ICE Brent 27.05 35.68 43.43 0.54 Collars: January 1, to June 30, 2021 9,000 ICE Brent 35.56 45.22 52.48 n/a Swaptions: July 1, to December 31, 2021 3,000 ICE Brent n/a n/a 56.75 n/a Foreign Currency Derivatives The Company utilizes foreign currency derivatives to manage the variability in cash flows associated with the Company's forecasted Colombian peso ("COP") denominated expenses. At September 30, 2020, the Company had outstanding foreign currency derivative positions as follows: Period and type of instrument Amount Hedged U.S. Dollar Equivalent of Amount Hedged (Thousands of U.S. Dollars) (1) Reference Floor Price Cap Price (COP, Weighted Average) Collars: October 1, to December 31, 2020 36,750 9,474 COP 3,306 3,425 (1) At September 30, 2020 foreign exchange rate.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	9 Months Ended
	Sep. 30, 2020
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow InformationThe following table provides a reconciliation of cash and cash equivalents and restricted cash and cash equivalents with the Company's interim unaudited condensed consolidated balance sheet that sum to the total of the same such amounts shown in the interim unaudited condensed consolidated statements of cash flows: (Thousands of U.S. Dollars) As at September 30, As at December 31, 2020 2019 2019 2018 Cash and cash equivalents $ 21,385 $ 13,959 $ 8,301 $ 51,040 Restricted cash and cash equivalents - current 423 676 516 1,269 Restricted cash and cash equivalents - 3,007 2,119 2,258 1,999 $ 24,815 $ 16,754 $ 11,075 $ 54,308 Net changes in assets and liabilities from operating activities were as follows: Nine Months Ended September 30, (Thousands of U.S. Dollars) 2020 2019 Accounts receivable and other long-term assets $ 31,108 $ 3,476 Derivatives 694 (658) Inventory (2,377) (3,403) Prepaids (183) 353 Accounts payable and accrued and other long-term liabilities (57,621) (21,687) Taxes receivable and payable 51,667 (61,687) Net changes in assets and liabilities from operating activities $ 23,288 $ (83,606) Changes in non-cash investing working capital for the nine months ended September 30, 2020, are comprised of a decrease in accounts payable and accrued liabilities of $69.9 million and an increase in accounts receivable of $0.3 million (nine months ended September 30, 2019, an increase in accounts payable and accrued liabilities of $19.7 million and an increase in accounts receivable of $0.4 million). The following table provides additional supplemental cash flow disclosures: Nine Months Ended September 30, (Thousands of U.S. Dollars) 2020 2019 Cash paid for income taxes $ 11,603 $ 38,022 Cash paid for interest $ 35,408 $ 25,850 Non-cash investing activities: Net liabilities related to property, plant and equipment, end of period $ 7,805 $ 105,342

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation	These interim unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”). The information furnished herein reflects all normal recurring adjustments that are, in the opinion of management, necessary for the fair presentation of results for the interim periods.
Recently Adopted Accounting Pronouncements/Recently Issued but Not Yet Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements Financial Instruments - Credit Losses (ASC 326) In June 2016, the FASB issued ASU 2016-13, "Financial Instruments - Credit Losses". This ASU replaces the incurred loss impairment methodology with a methodology that reflects expected credit losses and requires a broader range of reasonable and supportable information to support credit loss estimates. In December 2019, the FASB issued ASU 2019-10, "Financial Instruments - Credit Losses, Derivatives and Hedging and Leases", which is codification improvement of ASU 2016-13. The Company adopted this ASU on January 1, 2020, the adoption of which had no impact on the Company. At each reporting date, the Company assesses the expected lifetime credit losses on initial recognition of trade accounts receivable. Credit risk is assessed based on the number of days the receivable has been outstanding and the internal credit assessment of the customer. The expected loss rates are based on payment profiles over a period of 36 months prior to the period-end and the corresponding historical credit losses experienced within this period. Historical loss rates are adjusted to reflect current and forward looking economic factors of the country where the Company sells oil that affect the ability of the customers to settle the receivables. Trade receivables are written off when there is no reasonable expectation of recovery. Risks and Measurement Uncertainty In March 2020, the outbreak of the COVID-19 virus, which was declared a pandemic by the World Health Organization, has spread across the globe and impacted worldwide economic activity. In addition, global commodity prices declined significantly due to disputes between major oil producing countries combined with the impact of the COVID-19 pandemic and associated reductions in global demand for oil. Governments worldwide, including those in Colombia and Ecuador, the countries where the Company operates, enacted emergency measures to combat the spread of the virus. These measures, which include the implementation of travel bans, self-imposed quarantine periods and physical distancing, caused material disruption to businesses globally resulting in an economic slowdown. Governments and central banks have reacted with significant monetary and fiscal interventions designed to stabilize economic conditions; however, the success of these interventions is not currently determinable. The current challenging economic climate is having and may continue to have significant adverse impacts on the Company including, but not exclusively: • material declines in revenue and cash flows as a result of the decline in commodity prices; • declines in revenue and operating activities due to reduced capital programs and the shut-in of production; • impairment charges (see Note 4); • inability to comply with covenants and restrictions in debt agreements; • inability to access financing sources; • increased risk of non-performance by the Company’s customers and suppliers; • interruptions in operations as the Company adjusts personnel to the dynamic environment; and • inability to operate or delay in operations as a result COVID-19 restrictions in the countries in which the Company operates. The unprecedented decline in oil prices has materially reduced the Company’s forecasted EBITDAX and the estimated value of its oil reserves. Based on current forecasted Brent pricing and production levels, which can change materially in very short time frames, the Company is forecasted to be in compliance with the amended financial covenants contained in the Company's Senior Secured Credit Facility (the "revolving credit facility") for at least the next year from the date of these financial statements. The amount available under the Company’s senior secured credit facility is based on the lenders determination of the borrowing base. The borrowing base is determined, by the lenders, based on the Company’s reserves and commodity prices. The next renewal of the borrowing base is scheduled for November 2020 and there is risk that the borrowing base may be reduced by the lenders. In addition, the Company’s ability to borrow under the credit facility may be limited by the terms of the indentures for the 6.25% Senior Notes and 7.75% Senior Notes. The risk of non-compliance with the covenants in the lending agreements and the risk associated with maintaining the borrowing base is heightened in the current period of volatility coupled with the unprecedented disruption caused by the COVID-19 pandemic. Management currently expects that the Company will continue to meet the terms of the credit facility or obtain further amendments or waivers if and when required. The Company also expects to be able to maintain the borrowing base at a level in excess of the amount borrowed. However, there can be no assurances that the Company’s liquidity can be maintained at or above current levels during this period of volatility and global economic uncertainty. The situation is dynamic and the ultimate duration and magnitude of the impact on the economy and the financial effect on the Company is not known at this time. Estimates and judgments made by management in the preparation of the financial statements are increasingly difficult and subject to a higher degree of measurement uncertainty during this volatile period. In the near term, matters in these financial statements that are most subject to be impacted by this volatile period are the Company's assessment of liquidity and access to capital, the carrying value of long-lived assets and the valuation of the deferred tax assets.

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	9 Months Ended
	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	(Thousands of U.S. Dollars) As at September 30, 2020 As at December 31, 2019 Oil and natural gas properties Proved $ 3,937,361 $ 3,850,565 Unproved 285,276 310,809 4,222,637 4,161,374 Other (1) 32,297 26,287 4,254,934 4,187,661 Accumulated depletion and depreciation and impairment (3,247,583) (2,610,268) $ 1,007,351 $ 1,577,393 (1) Included in other are right-of-use assets for operating and finance leases, net book value of which was $5.1 million as at September 30, 2020 ($5.7 million as at December 31, 2019).

Debt and Debt Issuance Costs (T

Debt and Debt Issuance Costs (Tables)	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Schedule of Debt	The Company's debt at September 30, 2020 and December 31, 2019 was as follows: (Thousands of U.S. Dollars) As at September 30, 2020 As at December 31, 2019 6.25% Senior Notes $ 300,000 $ 300,000 7.75% Senior Notes 300,000 300,000 Revolving credit facility 200,000 118,000 Unamortized debt issuance costs (18,925) (21,081) Long-term debt 781,075 696,919 Long-term lease obligation (1) 3,236 3,540 $ 784,311 $ 700,459 (1) The current portion of the lease obligation has been included in accounts payable and accrued liabilities on the Company's balance sheet and totaled $3.3 million as at September 30, 2020 (December 31, 2019 - $3.3 million).
Schedule of Interest Expense Recognized	The following table presents total interest expense recognized in the accompanying interim unaudited condensed consolidated statements of operations: Three Months Ended September 30, Nine Months Ended September 30, (Thousands of U.S. Dollars) 2020 2019 2020 2019 Contractual interest and other financing expenses $ 13,191 $ 11,364 $ 37,430 $ 28,081 Amortization of debt issuance costs 838 789 2,774 2,574 $ 14,029 $ 12,153 $ 40,204 $ 30,655

Share Capital (Tables)

Share Capital (Tables)	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Schedule of Common Stock	Shares of Common Stock Balance at December 31, 2019 and September 30, 2020 366,981,556
Schedule of PSU, DSU, RSU and Stock Option Activity	The following table provides information about p erformance stock units (“PSUs”), deferred share units (“DSUs”), and stock option activity for the nine months ended September 30, 2020: PSUs DSUs Stock Options Number of Outstanding Share Units Number of Outstanding Share Units Number of Outstanding Stock Options Weighted Average Exercise Price/Stock Option ($) Balance, December 31, 2019 11,371,367 1,251,994 10,612,872 2.78 Granted 16,063,219 1,708,720 8,653,255 0.71 Exercised (2,531,995) — — — Forfeited (1,629,187) — (992,287) 2.02 Expired — — (2,847,970) 3.48 Balance, September 30, 2020 23,273,404 2,960,714 15,425,870 1.56
Schedule of Weighted Average Shares Outstanding	Weighted Average Shares Outstanding Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Weighted average number of common shares outstanding 366,981,556 372,195,176 366,981,556 379,701,405 Shares issuable pursuant to stock options — — — 14,315 Shares assumed to be purchased from proceeds of stock options — — — (14,056) Weighted average number of diluted common shares outstanding 366,981,556 372,195,176 366,981,556 379,701,664 Common shares outstanding, as at period end 366,981,556 366,981,556 366,981,556 366,981,556

COVID-19 Costs (Tables)

COVID-19 Costs (Tables)	9 Months Ended
	Sep. 30, 2020
Unusual or Infrequent Items, or Both [Abstract]
Schedule Cost Incurred due to Catastrophic Events	The COVID-19 pandemic resulted in extra operating and transportation costs related to COVID-19 health and safety preventative measures including incremental sanitation requirements and enhanced procedures for trucking barrels and crew changes in the field. Below is a break-down of the costs: Three Months Ended September 30, Nine Months Ended September 30, (Thousands of U.S. Dollars) 2020 2019 2020 2019 Operating expenses $ 1,012 $ — $ 1,433 $ — Transportation costs 96 — 96 — COVID-19 costs $ 1,108 $ — $ 1,529 $ —

Financial Instruments and Fai_2

Financial Instruments and Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Derivatives and RSU, PSU and DSU Liabilities	The fair value of investment, derivatives and PSUs and DSUs liability at September 30, 2020, and December 31, 2019, was as follows: (Thousands of U.S. Dollars) As at September 30, 2020 As at December 31, 2019 Investment $ 33,209 $ 94,741 Derivative liability $ 3,184 $ 775 PSUs and DSUs liability 2,327 7,859 $ 5,511 $ 8,634
Schedule of Gains or Losses on Financial Instruments Recognized	The following table presents gains or losses on financial instruments recognized in the accompanying interim unaudited condensed consolidated statements of operations: Three Months Ended September 30, Nine Months Ended September 30, (Thousands of U.S. Dollars) 2020 2019 2020 2019 Commodity price derivative (gain) loss $ (2,206) $ (24) $ (12,983) $ 464 Foreign currency derivatives loss 33 337 3,566 392 Investment loss (gain) 1,055 11,972 60,124 (3,746) Financial instruments loss 405 — 1,162 — $ (713) $ 12,285 $ 51,869 $ (2,890)
Schedule of Commodity Price Derivative Positions and Commodity Foreign Currency Contracts	At September 30, 2020, the Company had outstanding commodity price derivative positions as follows: Period and type of instrument Volume, Reference Sold Put ($/bbl, Weighted Average) Purchased Put ($/bbl, Weighted Average) Sold Call ($/bbl, Weighted Average) Premium ($/bbl, Weighted Average) Collars: October 1, to December 31, 2020 11,000 ICE Brent 27.05 35.68 43.43 0.54 Collars: January 1, to June 30, 2021 9,000 ICE Brent 35.56 45.22 52.48 n/a Swaptions: July 1, to December 31, 2021 3,000 ICE Brent n/a n/a 56.75 n/a
Schedule of Outstanding Foreign Currency Derivative Positions	At September 30, 2020, the Company had outstanding foreign currency derivative positions as follows: Period and type of instrument Amount Hedged U.S. Dollar Equivalent of Amount Hedged (Thousands of U.S. Dollars) (1) Reference Floor Price Cap Price (COP, Weighted Average) Collars: October 1, to December 31, 2020 36,750 9,474 COP 3,306 3,425 (1) At September 30, 2020 foreign exchange rate.

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2020
Supplemental Cash Flow Elements [Abstract]
Reconciliation of Cash, Cash Equivalents and Restricted Cash and Cash Equivalents	The following table provides a reconciliation of cash and cash equivalents and restricted cash and cash equivalents with the Company's interim unaudited condensed consolidated balance sheet that sum to the total of the same such amounts shown in the interim unaudited condensed consolidated statements of cash flows: (Thousands of U.S. Dollars) As at September 30, As at December 31, 2020 2019 2019 2018 Cash and cash equivalents $ 21,385 $ 13,959 $ 8,301 $ 51,040 Restricted cash and cash equivalents - current 423 676 516 1,269 Restricted cash and cash equivalents - 3,007 2,119 2,258 1,999 $ 24,815 $ 16,754 $ 11,075 $ 54,308
Schedule of Net Changes in Assets and Liabilities	Net changes in assets and liabilities from operating activities were as follows: Nine Months Ended September 30, (Thousands of U.S. Dollars) 2020 2019 Accounts receivable and other long-term assets $ 31,108 $ 3,476 Derivatives 694 (658) Inventory (2,377) (3,403) Prepaids (183) 353 Accounts payable and accrued and other long-term liabilities (57,621) (21,687) Taxes receivable and payable 51,667 (61,687) Net changes in assets and liabilities from operating activities $ 23,288 $ (83,606)
Schedule of Additional Supplemental Cash Flow Disclosures	The following table provides additional supplemental cash flow disclosures: Nine Months Ended September 30, (Thousands of U.S. Dollars) 2020 2019 Cash paid for income taxes $ 11,603 $ 38,022 Cash paid for interest $ 35,408 $ 25,850 Non-cash investing activities: Net liabilities related to property, plant and equipment, end of period $ 7,805 $ 105,342

Significant Accounting Polici_3

Significant Accounting Policies (Details) - Senior notes	Sep. 30, 2020
6.25% Senior Notes
Debt Instrument [Line Items]
Stated interest rate	6.25%
7.75% Senior Notes
Debt Instrument [Line Items]
Stated interest rate	7.75%

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 4,254,934	$ 4,187,661
Accumulated depletion and depreciation and impairment	(3,247,583)	(2,610,268)
Total Property, Plant and Equipment (Notes 5)	1,007,351	1,577,393
Right-of-use asset	5,100	5,700
Oil and natural gas properties
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,222,637	4,161,374
Proved
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	3,937,361	3,850,565
Unproved
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	285,276	310,809
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 32,297	$ 26,287

Impairment (Details)

Impairment (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)$ / bbl	Sep. 30, 2019USD ($)$ / bbl
Property, Plant and Equipment [Line Items]
Impairment of oil and gas properties	$ 104,700,000		$ 502,900,000
Oil and gas properties, discounted rate			10.00%
Historical prices, discounted rate			10.00%
Ceiling test impairment		$ 0	$ 0
Inventory impairment	100,000	0	4,200,000	$ 0
Goodwill impairment	$ 0	$ 0	$ 102,581,000	$ 0
Crude Oil and NGL
Property, Plant and Equipment [Line Items]
Average Brent price per barrel (in USD per barrel) | $ / bbl			47.95	67.20

Debt and Debt Issuance Costs -

Debt and Debt Issuance Costs - Schedule of Debt (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ (18,925,000)	$ (21,081,000)
Long-term debt	781,075,000	696,919,000
Long-term lease obligation	3,236,000	3,540,000
Long-term debt excluding current maturity	$ 784,311,000	700,459,000
Senior notes | 6.25% Senior Notes
Debt Instrument [Line Items]
Stated interest rate	6.25%
Convertible senior notes and revolving credit facility	$ 300,000,000	300,000,000
Senior notes | 7.75% Senior Notes
Debt Instrument [Line Items]
Stated interest rate	7.75%
Convertible senior notes and revolving credit facility	$ 300,000,000	300,000,000
Revolving credit facility | Revolving credit facility
Debt Instrument [Line Items]
Convertible senior notes and revolving credit facility	200,000,000	118,000,000
Lease obligations | Accounts payable
Debt Instrument [Line Items]
Current portion of lease obligation	$ 3,300,000	$ 3,300,000

Debt and Debt Issuance Costs _2

Debt and Debt Issuance Costs - Narrative (Details) - Revolving credit facility - Revolving credit facility - USD ($)	3 Months Ended
	Sep. 30, 2020	Oct. 01, 2021	Jun. 01, 2020	May 31, 2020
Line of Credit Facility [Line Items]
Borrowing base			$ 225,000,000	$ 300,000,000
Increase in spread during covenant relief	1.25%
Requirements for borrowing condition, maximum balance of cash and cash equivalents	$ 15,000,000
Minimum
Line of Credit Facility [Line Items]
Debt to EBITDAX ratio			400.00%
Minimum | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	2.90%
Minimum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.90%
Minimum | March 31, 2021
Line of Credit Facility [Line Items]
EBITDAX to interest expense, ratio			200.00%
Maximum
Line of Credit Facility [Line Items]
Senior secured debt to EBITDAX ratio			250.00%
Maximum | Forecast
Line of Credit Facility [Line Items]
Debt to EBITDAX ratio		400.00%
Senior secured debt to EBITDAX ratio		300.00%
EBITDAX to interest expense, ratio		250.00%
Maximum | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	4.90%
Maximum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	3.90%
Maximum | Until December 31.2020
Line of Credit Facility [Line Items]
EBITDAX to interest expense, ratio			250.00%

Debt and Debt Issuance Costs _3

Debt and Debt Issuance Costs - Schedule of Interest Expense Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Debt Disclosure [Abstract]
Contractual interest and other financing expenses	$ 13,191	$ 11,364	$ 37,430	$ 28,081
Amortization of debt issuance costs	838	789	2,774	2,574
Total interest expense recognized	$ 14,029	$ 12,153	$ 40,204	$ 30,655

Share Capital - Schedule of Com

Share Capital - Schedule of Common Stock (Details) - shares	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Increase (Decrease) in Common Stock
Common Stock, shares outstanding (in shares)	366,981,556	366,981,556	366,981,556
Shares of Common Stock
Increase (Decrease) in Common Stock
Common Stock, shares outstanding (in shares)	366,981,556	366,981,556

Share Capital - Schedule of PSU

Share Capital - Schedule of PSU, DSU, RSU and Stock Option Activity (Details)	9 Months Ended
	Sep. 30, 2020$ / sharesshares
Number of Outstanding Stock Options
Beginning Balance (in shares)	10,612,872
Granted (in shares)	8,653,255
Exercised (in shares)	0
Forfeited (in shares)	(992,287)
Expired (in shares)	(2,847,970)
Ending Balance (in shares)	15,425,870
Weighted Average Exercise Price/Stock Option ($)
Beginning balance (in dollars per share) | $ / shares	$ 2.78
Granted (in dollars per share) | $ / shares	0.71
Exercised (in dollars per share) | $ / shares	0
Forfeited (in dollars per share) | $ / shares	2.02
Expired (in dollars per share) | $ / shares	3.48
Ending balance (in dollars per share) | $ / shares	$ 1.56
PSUs
Number of Outstanding Share Units
Beginning Balance (in shares)	11,371,367
Granted (in shares)	16,063,219
Exercised (in shares)	(2,531,995)
Forfeited (in shares)	(1,629,187)
Expired (in shares)	0
Ending Balance (in shares)	23,273,404
DSUs
Number of Outstanding Share Units
Beginning Balance (in shares)	1,251,994
Granted (in shares)	1,708,720
Exercised (in shares)	0
Forfeited (in shares)	0
Expired (in shares)	0
Ending Balance (in shares)	2,960,714

Share Capital - Equity Compensa

Share Capital - Equity Compensation Awards (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 1.3	$ 0	$ (0.7)	$ 1.1
Unrecognized compensation cost	$ 5.3		$ 5.3		$ 6.7
Weighted average period for recognition			1 year 9 months 18 days
PSUs | Vested December 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payments for units vested in period			$ 3.2
PSUs | Vested December 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payments for units vested in period				$ 10.2

Share Capital - Schedule of Wei

Share Capital - Schedule of Weighted Average Shares Outstanding (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Weighted average number of common shares outstanding (in shares)	366,981,556	372,195,176	366,981,556	379,701,405
Shares issuable pursuant to stock options (in shares)	0	0	0	14,315
Shares assumed to be purchased from proceeds of stock options (in shares)	0	0	0	(14,056)
Weighted average number of diluted common shares outstanding (in shares)	366,981,556	372,195,176	366,981,556	379,701,664
Common shares outstanding, as at period end (in shares)	366,981,556	366,981,556	366,981,556	366,981,556	366,981,556

Share Capital - Weighted Averag

Share Capital - Weighted Average Shares Outstanding (Narrative) (Details) - shares	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Options excluded from diluted income (loss) per share calculation (in shares)	10,316,496	10,247,016

Revenue (Details)

Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Concentration Risk [Line Items]
Variable adjustment for transportation, location, quality, and other elements, percentage	(22.00%)	(16.00%)	(27.00%)	(15.00%)
Accrued sales revenue	$ 0		$ 0		$ 0.1
Product Concentration Risk | Revenue from Contract with Customer
Concentration Risk [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%

COVID-19 Costs (Details)

COVID-19 Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Unusual or Infrequent Items, or Both [Abstract]
Operating expenses	$ 1,012	$ 0	$ 1,433	$ 0
Transportation costs	96	0	96	0
COVID-19 costs	$ 1,108	$ 0	$ 1,529	$ 0

Taxes (Details)

Taxes (Details)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Income Tax Contingency [Line Items]
Effective tax rate	8.00%	79.00%
Unrealized loss of investment as percent of non-deductible portion	50.00%
Colombia
Income Tax Contingency [Line Items]
Statutory income tax rate	32.00%	33.00%

Contingencies (Details)

Contingencies (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Letters of credit and other credit support provided	$ 96.6	$ 120.6

Financial Instruments and Fai_3

Financial Instruments and Fair Value Measurement - Narrative (Details) $ in Thousands, shares in Millions	Sep. 30, 2020USD ($)shares	Sep. 30, 2020$ / shares	Dec. 31, 2019USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	$ 33,209		$ 94,741
Senior notes | 6.25% Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	6.25%
Senior notes | 7.75% Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	7.75%
Fair value | Senior notes | 6.25% Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	$ 103,600
Fair value | Senior notes | 7.75% Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	105,600
Carrying amount | Senior notes | 6.25% Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	291,900
Carrying amount | Senior notes | 7.75% Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	290,600
PetroTal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	$ 33,200
Closing share price (in dollars per share) | $ / shares		$ 0.18
PetroTal | Fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment owned, balance (in shares) | shares	246
Investment owned, percent of total shares	30.00%

Financial Instruments and Fai_4

Financial Instruments and Fair Value Measurement - Schedule of Fair Value of Derivatives and RSU, PSU and DSU Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Investment	$ 33,209	$ 94,741
Derivative liability	3,184	775
PSU and DSU liability	2,327	7,859
Liabilities, fair value disclosure	$ 5,511	$ 8,634

Financial Instruments and Fai_5

Financial Instruments and Fair Value Measurement - Schedule of Gains or Losses on Financial Instruments Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Investment loss (gain)	$ 1,055	$ 11,972	$ 60,124	$ (3,746)
Financial instruments loss	405	0	1,162	0
Financial instruments (gain) loss	(713)	12,285	51,869	(2,890)
Commodity price derivative (gain) loss
Derivative Instruments, Gain (Loss) [Line Items]
Derivative (gain) loss	(2,206)	(24)	(12,983)	464
Foreign currency derivatives loss
Derivative Instruments, Gain (Loss) [Line Items]
Derivative (gain) loss	$ 33	$ 337	$ 3,566	$ 392

Financial Instruments and Fai_6

Financial Instruments and Fair Value Measurement - Schedule of Commodity Price Derivative Positions and Commodity Foreign Currency Contracts (Details) - Forecast	3 Months Ended	6 Months Ended
	Dec. 31, 2020$ / bbl$ / collarbbl	Dec. 31, 2021$ / bblbbl	Jun. 30, 2021$ / bblbbl
Collars: October 1, to December 31, 2020 | Sold | Put
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Purchased Put (in dollars per barrel) | $ / collar	3,306
Collars: October 1, to December 31, 2020 | Purchased | Call
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Sold Price (Weighted Average) (in dollars per bbl) | $ / collar	3,425
Commodity Hedge | Collars: October 1, to December 31, 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (in barrels of oil per day) | bbl	11,000
Premium (Weighted Average) (in dollars per bbl)	0.54
Commodity Hedge | Collars: October 1, to December 31, 2020 | Sold | Put
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Sold Price (Weighted Average) (in dollars per bbl)	27.05
Commodity Hedge | Collars: October 1, to December 31, 2020 | Sold | Call
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Sold Price (Weighted Average) (in dollars per bbl)	43.43
Commodity Hedge | Collars: October 1, to December 31, 2020 | Purchased | Put
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Purchased Put (in dollars per barrel)	35.68
Commodity Hedge | Collars: January 1, to June 30, 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (in barrels of oil per day) | bbl			9,000
Commodity Hedge | Collars: January 1, to June 30, 2021 | Sold | Put
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Sold Price (Weighted Average) (in dollars per bbl)			35.56
Commodity Hedge | Collars: January 1, to June 30, 2021 | Sold | Call
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Sold Price (Weighted Average) (in dollars per bbl)			52.48
Commodity Hedge | Collars: January 1, to June 30, 2021 | Purchased | Put
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Purchased Put (in dollars per barrel)			45.22
Commodity Hedge | Swaptions: July 1, to December 31, 2021 [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (in barrels of oil per day) | bbl		3,000
Commodity Hedge | Swaptions: July 1, to December 31, 2021 [Member] | Sold | Call
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Sold Price (Weighted Average) (in dollars per bbl)		56.75

Financial Instruments and Fai_7

Financial Instruments and Fair Value Measurement - Schedule of Outstanding Foreign Currency Derivative Positions (Details) - Forecast - Collars: October 1, to December 31, 2020 $ in Thousands, $ in Thousands	Dec. 31, 2020COP ($)$ / collar	Dec. 31, 2020USD ($)$ / collar
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount Hedged	$ 36,750	$ 9,474
Sold | Put
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Floor Price (COP, Weighted Average)	3,306	3,306
Purchased | Call
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cap Price (COP, Weighted Average)	3,425	3,425

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information - Reconciliation of Cash, Cash Equivalents and Restricted Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents	$ 21,385	$ 8,301	$ 13,959	$ 51,040
Restricted cash and cash equivalents - current	423	516	676	1,269
Restricted cash and cash equivalents - long-term (included in other long-term assets)	3,007	2,258	2,119	1,999
Cash, cash equivalents and restricted cash and cash equivalents	$ 24,815	$ 11,075	$ 16,754	$ 54,308

Supplemental Cash Flow Inform_4

Supplemental Cash Flow Information - Schedule of Net Changes in Assets and Liabilities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Accounts receivable and other long-term assets	$ 31,108	$ 3,476
Derivatives	694	(658)
Inventory	(2,377)	(3,403)
Prepaids	(183)	353
Accounts payable and accrued and other long-term liabilities	(57,621)	(21,687)
Taxes receivable and payable	51,667	(61,687)
Net changes in assets and liabilities from operating activities	23,288	(83,606)
Increase (decrease) in accounts payable and accrued liabilities	(69,900)	19,700
Increase in accounts receivable	$ 300	$ 400

Supplemental Cash Flow Inform_5

Supplemental Cash Flow Information - Schedule of Additional Supplemental Cash Flow Disclosures (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Cash paid for income taxes	$ 11,603	$ 38,022
Cash paid for interest	35,408	25,850
Non-cash investing activities:
Net liabilities related to property, plant and equipment, end of period	$ 7,805	$ 105,342