Gran Tierra Energy (GTE) 10-Q 2 Nov 21 2021 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2021	Oct. 29, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
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		367,144,500
Entity Central Index Key	0001273441
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
OIL SALES (Note 8)	$ 135,319	$ 53,142	$ 327,435	$ 173,045
EXPENSES
Operating	37,567	20,721	92,623	84,673
Transportation	3,021	1,286	8,448	8,549
COVID-19 related costs (Note 9)	990	1,108	3,026	1,529
Depletion, depreciation and accretion	38,055	31,340	98,300	131,118
Goodwill impairment (Note 5)	0	0	0	102,581
Asset impairment (Note 5)	0	104,731	0	507,093
General and administrative	6,497	4,562	25,072	16,476
Severance	0	122	919	1,469
Foreign exchange loss	2,650	4,275	15,824	20,094
Derivative instruments loss (gain) (Note 12)	2,603	(2,173)	47,540	(9,417)
Other financial instruments (gain) loss (Note 12)	(13,634)	1,460	(12,425)	61,286
Other loss	0	67	0	67
Interest expense (Note 6)	13,608	14,029	41,355	40,204
EXPENSES	91,357	181,528	320,682	965,722
INTEREST INCOME	0	0	0	345
INCOME (LOSS) BEFORE INCOME TAXES	43,962	(128,386)	6,753	(792,332)
INCOME TAX EXPENSE (RECOVERY)
Current (Note 10)	0	637	(14)	560
Deferred (Note 10)	8,955	(21,202)	26,809	(62,796)
INCOME TAX EXPENSE (RECOVERY)	8,955	(20,565)	26,795	(62,236)
NET AND COMPREHENSIVE INCOME (LOSS)	35,007	(107,821)	(20,042)	(730,096)
NET AND COMPREHENSIVE INCOME (LOSS)	$ 35,007	$ (107,821)	$ (20,042)	$ (730,096)
NET INCOME (LOSS) PER SHARE
BASIC (in dollars per share)	$ 0.10	$ (0.29)	$ (0.05)	$ (1.99)
DILUTED (in dollars per share)	$ 0.10	$ (0.29)	$ (0.05)		$ (1.99)
WEIGHTED AVERAGE SHARES OUTSTANDING - BASIC (Note 7) (in shares)	366,992,802	366,981,556	366,985,646	366,981,556
WEIGHTED AVERAGE SHARES OUTSTANDING - DILUTED (Note 7) (in shares)	367,740,722	366,981,556	366,985,646	366,981,556

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current Assets
Cash and cash equivalents (Note 13)	$ 16,600	$ 14,114
Accounts receivable	26,431	8,044
Investment (Note 12)	44,116	48,323
Taxes receivable (Note 3)	47,772	49,925
Other current assets	17,141	13,459
Total Current Assets	152,060	133,865
Oil and Gas Properties
Proved	833,069	797,355
Unproved	158,483	161,763
Total Oil and Gas Properties	991,552	959,118
Other capital assets	3,085	5,364
Total Property, Plant and Equipment (Note 4)	994,637	964,482
Other Long-Term Assets
Deferred tax assets	13,349	57,318
Taxes receivable (Note 3)	14,447	42,635
Restricted cash and cash equivalents (Note 13)	3,532	3,409
Other	3,233	16
Total Other Long-Term Assets	34,561	103,378
Total Assets	1,181,258	1,201,725
Current Liabilities
Accounts payable and accrued liabilities	114,785	100,784
Derivatives (Note 12)	14,737	12,050
Taxes payable (Note 3)	5,938	0
Equity compensation award liability (Note 7 and 12)	2,132	805
Total Current Liabilities	137,592	113,639
Long-Term Liabilities
Long-term debt (Notes 6 and 12)	735,411	774,770
Asset retirement obligation	54,356	48,214
Equity compensation award liability (Note 7 and 12)	11,469	3,955
Other long-term liabilities	3,563	4,113
Total Long-Term Liabilities	804,799	831,052
Contingencies (Note 11)
Shareholders' Equity
Common Stock (Note 7) (367,038,454 and 366,981,556 shares issued and outstanding of Common Stock, par value $0.001 per share, as at September 30, 2021, and December 31, 2020, respectively)	10,270	10,270
Additional paid-in capital	1,286,893	1,285,018
Deficit	(1,058,296)	(1,038,254)
Total Shareholders' Equity	238,867	257,034
Total Liabilities and Shareholders’ Equity	$ 1,181,258	$ 1,201,725

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Common Stock, shares issued (in shares)	367,038,454	366,981,556
Common Stock, shares outstanding (in shares)	367,038,454	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 ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating Activities
Net loss	$ (20,042)	$ (730,096)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depletion, depreciation and accretion	98,300	131,118
Goodwill impairment (Note 5)	0	102,581
Asset impairment (Note 5)	0	507,093
Deferred tax expense (recovery)	26,809	(62,796)
Stock-based compensation expense (recovery) (Note 7)	6,597	(707)
Amortization of debt issuance costs (Note 6)	2,682	2,774
Unrealized foreign exchange loss	16,945	22,335
Derivative instruments loss (gain) (Note 12)	47,540	(9,417)
Cash settlements on derivatives instruments	(45,041)	9,970
Other financial instruments (gain) loss (Note 12)	(12,425)	61,286
Other non-cash loss	0	2,026
Cash settlement of asset retirement obligation	(483)	(199)
Non-cash lease expenses	1,222	1,494
Lease payments	(1,239)	(1,404)
Net change in assets and liabilities from operating activities (Note 13)	17,956	23,288
Net cash provided by operating activities	138,821	59,346
Investing Activities
Additions to property, plant and equipment	(109,650)	(56,378)
Proceeds on disposition of investment, net of transaction costs (Note 12)	14,632	0
Changes in non-cash investing working capital (Note 13)	709	(69,549)
Net cash used in investing activities	(94,309)	(125,927)
Financing Activities
Proceeds from debt, net of issuance costs (Note 6)	(125)	88,382
Repayment of debt (Note 6)	(40,000)	(7,000)
Proceeds from exercise of stock options	19	0
Lease payments	(1,269)	(307)
Net cash (used in) provided by financing activities	(41,375)	81,075
Foreign exchange loss on cash, cash equivalents and restricted cash and cash equivalents	(528)	(754)
Net increase in cash, cash equivalents and restricted cash and cash equivalents	2,609	13,740
Cash, cash equivalents and restricted cash and cash equivalents, beginning of period (Note 13)	17,523	11,075
Cash, cash equivalents and restricted cash and cash equivalents, end of period (Note 13)	$ 20,132	$ 24,815

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Share Capital	Additional Paid-in Capital	Deficit
Balance, beginning of period at Dec. 31, 2019		$ 10,270	$ 1,282,627	$ (260,287)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options			0
Stock-based compensation (Note 7)			1,778
Net income (loss)	$ (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)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options			0
Stock-based compensation (Note 7)			607
Net income (loss)	(107,821)			(107,821)
Balance, end of period at Sep. 30, 2020	304,292	10,270	1,284,405	(990,383)
Balance, beginning of period at Dec. 31, 2020		10,270	1,285,018	(1,038,254)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options			18
Stock-based compensation (Note 7)			1,857
Net income (loss)	(20,042)			(20,042)
Balance, end of period at Sep. 30, 2021	238,867	10,270	1,286,893	(1,058,296)
Balance, beginning of period at Jun. 30, 2021		10,270	1,286,235	(1,093,303)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options			10
Stock-based compensation (Note 7)			648
Net income (loss)	35,007			35,007
Balance, end of period at Sep. 30, 2021	$ 238,867	$ 10,270	$ 1,286,893	$ (1,058,296)

Description of Business

Description of Business	9 Months Ended
	Sep. 30, 2021
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 international oil and natural gas exploration and production with assets currently in Colombia and Ecuador.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
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, 2020, included in the Company's 2020 Annual Report on Form 10-K.

Taxes Receivable and Payable

Taxes Receivable and Payable	9 Months Ended
	Sep. 30, 2021
Tax Receivable Agreement [Abstract]
Taxes Receivable and Payable	Taxes Receivable and Payable The table below shows the break-down of taxes receivable and payable, which are comprised of value added tax ("VAT") and income tax: (Thousands of U.S. Dollars) As at September 30, 2021 As at December 31, 2020 Taxes Receivable Current VAT Receivable $ 31,890 $ 35,977 Income Tax Receivable 15,882 13,948 $ 47,772 $ 49,925 Long-Term VAT Receivable $ — $ 28,485 Income Tax Receivable 14,447 14,150 $ 14,447 $ 42,635 Taxes Payable Current VAT Payable $ 5,938 $ — Total Taxes Receivable net of Taxes Payable $ 56,281 $ 92,560 The following table shows the movement of VAT and income tax receivables for the period identified below: (Thousands of U.S. Dollars) Net VAT Receivable Income Tax Receivable Total Net Taxes Receivable Balance, as at December 31, 2020 $ 64,462 $ 28,098 $ 92,560 Collected through direct government refunds (518) (14,228) (14,746) Collected through sales contracts (70,881) — (70,881) Taxes paid (1) 38,278 19,923 58,201 Foreign exchange loss (5,389) (3,464) (8,853) Balance, as at September 30, 2021 $ 25,952 $ 30,329 $ 56,281 (1) VAT is paid on certain goods and services in Colombia at a rate of 19%

Property, Plant and Equipment

Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment (Thousands of U.S. Dollars) As at September 30, 2021 As at December 31, 2020 Oil and natural gas properties Proved $ 4,236,548 $ 4,106,768 Unproved 158,483 161,763 4,395,031 4,268,531 Other (1) 32,779 32,135 4,427,810 4,300,666 Accumulated depletion and depreciation and impairment (3,433,173) (3,336,184) $ 994,637 $ 964,482 (1) The "other" category includes right-of-use assets for operating and finance leases of $11.7 million, which had a net book value of $2.5 million as at September 30, 2021 (December 31, 2020 - $11.4 million which had a net book value of $4.4 million).

Impairment

Impairment	9 Months Ended
	Sep. 30, 2021
Impairment Disclosure [Abstract]
Impairment	Impairment Asset impairment (i) Oil and gas property impairment For the three and nine months ended September 30, 2021, the Company had no ceiling test impairment losses. For each of the three and nine months ended September 30, 2020, Gran Tierra had $104.7 million and $502.9 million of ceiling test impairment losses. The Company used an average Brent price of $60.12 and $47.95 per bbl for the September 30, 2021 and 2020, ceiling test calculations, respectively. (ii) Inventory impairment For the three and nine months ended September 30, 2021, the Company had no inventory impairment. For the three and nine months ended September 30, 2020, the Company recorded $0.1 million and $4.2 million, respectively, of inventory impairment. Goodwill impairment The entire goodwill balance of $102.6 million was impaired during the nine months ended September 30, 2020, due to the reporting unit's carrying value exceeding its fair value due to the impact of lower forecasted commodity prices.

Debt and Debt Issuance Costs

Debt and Debt Issuance Costs	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Debt and Debt Issuance Costs	Debt and Debt Issuance CostsThe Company's debt at September 30, 2021, and December 31, 2020, was as follows: (Thousands of U.S. Dollars) As at September 30, 2021 As at December 31, 2020 6.25% Senior Notes, due February 2025 $ 300,000 $ 300,000 7.75% Senior Notes, due May 2027 300,000 300,000 Revolving credit facility 150,000 190,000 Unamortized debt issuance costs (15,566) (18,124) Long-term debt 734,434 771,876 Long-term lease obligation (1) 977 2,894 $ 735,411 $ 774,770 (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 $2.9 million as at September 30, 2021 (December 31, 2020 - $3.3 million). As at September 30, 2021, the borrowing base of the Company's Senior Secured Credit Facility (the "revolving credit facility") was $215 million. The maturity date of the revolving credit facility is October 2022 and the next re-determination to occur no later than November 2021. The Company is required to comply with various covenants, which were modified in response to market conditions including the COVID-19 pandemic until October 1, 2021 ("the covenant relief period"). During the covenant relief period, the Company's ratio of total debt to Covenant EBITDAX ("EBITDAX") was permitted to be greater than 4.0 to 1.0, Senior Secured Debt to EBITDAX ratio could 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 quarter ended September 30, 2021, was required to be 2.0 to 1.0. As of September 30, 2021, the Company was in compliance with all applicable covenants in the revolving credit facility. Commencing on October 1, 2021, 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. Amounts drawn down under the revolving credit facility bear interest, at the Company's option, at the USD LIBOR rate plus a margin ranging from 2.90% to 4.90%, or an alternate base rate plus a margin ranging from 1.90% to 3.90%, in each case based on the borrowing base utilization percentage. The alternate base rate is currently the U.S. prime rate. We pay a commitment fee on undrawn amounts under the revolving credit facility, which ranges from 0.73% to 1.23% per annum, based on the average daily amount of unused commitments. The Company's revolving credit facility is guaranteed by and secured against the assets of certain of the Company's subsidiaries (the "Credit Facility Group"). Under the terms of the revolving credit facility, the Company is subject to certain restrictions on its ability to distribute funds to entities outside of the Credit Facility Group, including restrictions on the ability to pay dividends to shareholders of the Company. 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) 2021 2020 2021 2020 Contractual interest and other financing expenses $ 12,701 $ 13,191 $ 38,673 $ 37,430 Amortization of debt issuance costs 907 838 2,682 2,774 $ 13,608 $ 14,029 $ 41,355 $ 40,204

Share Capital

Share Capital	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Share Capital	Share Capital Shares of Common Stock Balance, December 31, 2020 366,981,556 Shares issued on option exercise 56,898 Balance, September 30, 2021 367,038,454 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, 2021: 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, 2020 23,273,404 4,067,897 15,444,949 1.50 Granted 13,428,840 1,310,122 5,834,014 0.80 Exercised (2,733,209) — (56,898) 0.33 Forfeited (3,492,165) — (1,628,591) 0.90 Expired — — (1,279,641) 3.17 Balance, September 30, 2021 30,476,870 5,378,019 18,313,833 1.22 Net Income (Loss) per Share Basic net income (loss) per share is calculated by dividing net income (loss) attributable to common shareholders by the weighted average number of shares of common stock issued and outstanding during each period. Diluted net income (loss) per share is calculated using the treasury stock method for share-based compensation arrangements. The treasury stock method assumes that any proceeds obtained on the exercise of share-based compensation arrangements would be used to purchase common shares at the average market price during the period. The weighted average number of shares is then adjusted by the difference between the number of shares issued from the exercise of share-based compensation arrangements and shares repurchased from the related proceeds. Anti-dilutive shares represent potentially dilutive securities excluded from the computation of diluted income or loss per share as their impact would be anti-dilutive. Weighted Average Shares Outstanding Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Weighted average number of common shares outstanding 366,992,802 366,981,556 366,985,646 366,981,556 Shares issuable pursuant to stock options 1,574,305 — — — Shares assumed to be purchased from proceeds of stock options (826,385) — — — Weighted average number of diluted common shares outstanding 367,740,722 366,981,556 366,985,646 366,981,556

Revenue

Revenue	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Revenue	RevenueThe Company's revenues are generated from oil sales at prices that reflect the blended prices received upon shipment by the purchaser at defined sales points or 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, 2021, 100% (three and nine months ended September 30, 2020 - 100%) of the Company's revenue resulted from oil sales. During the three and nine months ended September 30, 2021, quality and transportation discounts were 16% and 15%, respectively, of the average ICE Brent price (three and nine months ended September 30, 2020 - 22% and 27%, respectively). During the three and nine months ended September 30, 2021, the Company's production was sold primarily to two major customers in Colombia (three and nine months ended September 30, 2020 - two).As at September 30, 2021, accounts receivable included nil of accrued sales revenue related to September 2021 production (December 31, 2020 - $0.1 million related to December 2020 production).

COVID-19 Costs

COVID-19 Costs	9 Months Ended
	Sep. 30, 2021
Unusual or Infrequent Items, or Both [Abstract]
COVID-19 Costs	COVID-19 Costs The COVID-19 pandemic has resulted in additional ongoing 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) 2021 2020 2021 2020 Operating expenses $ 881 $ 1,012 $ 2,743 $ 1,433 Transportation costs 109 96 283 96 Total COVID-19 costs $ 990 $ 1,108 $ 3,026 $ 1,529

Taxes

Taxes	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Taxes	TaxesThe Company's effective tax rate was 397% for the nine months ended September 30, 2021, compared to 8% in the comparative period of 2020. Current income tax was in a recovery position for the nine months ended September 30, 2021, versus an expense position for the comparative period in 2020, primarily as a result of changes in the previous estimation of presumptive minimum tax. The deferred income tax expense for the nine months ended September 30, 2021, resulted from excess tax depreciation compared to accounting depreciation and the use of tax losses to offset taxable income in Colombia. The deferred income tax recovery in the comparative period of 2020 was mainly the result of a ceiling test impairment loss in Colombia, partially offset by losses incurred in Colombia that are now fully offset by a valuation allowance. For the nine months ended September 30, 2021, the difference between the effective tax rate of 397% and the 31% Colombian tax rate was primarily due to the non-deductibility of derivative instrument losses and financing costs; foreign currency translation adjustments, and stock based compensation. These were partially offset by a decrease in the valuation allowance and the non-taxable portion (50%) of the unrealized gain on PetroTal Corp. ("PetroTal") shares. In the third quarter of 2021, Congressional authorities in Colombia enacted a new tax legislation, which includes an increase to the corporate income tax rate to 35% from 31%, effective January 1, 2022. Accordingly, the tax rates applied to the calculation of deferred income taxes, before valuation allowance, have been adjusted to reflect this change. 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, the non-deductibility of goodwill impairment for tax purposes, foreign translation adjustments and the non-deductible portion (50%) of the unrealized loss on PetroTal Corp. ("PetroTal") shares.

Contingencies

Contingencies	9 Months Ended
	Sep. 30, 2021
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 high price share royalties. 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, 2021, the Company had provided letters of credit and other credit support totaling $102.4 million (December 31, 2020 - $100.6 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, 2021
Fair Value Disclosures [Abstract]
Financial Instruments and Fair Value Measurement	Financial Instruments and Fair Value Measurement Financial Instruments At September 30, 2021, the Company’s financial instruments recognized on the balance sheet consisted of cash and cash equivalents, restricted cash and cash equivalents, accounts receivable, investment, other long-term assets, accounts payable and accrued liabilities, derivatives, equity compensation award liability, long-term debt, and other long-term liabilities. Fair Value Measurement The fair value of investment, derivatives, and equity compensation award liability is remeasured to the estimated fair value at the end of each reporting period. Investment in PetroTal The estimated fair value of the Company's investment in PetroTal was $44.1 million at September 30, 2021 ($48.3 million at December 31, 2020), based on the closing stock price of PetroTal of $0.41 CAD ($0.25 CAD at December 31, 2020) and the foreign exchange rate at that date. During the nine months ended September 30, 2021, the Company sold 44% (109 million common shares) of its interest in PetroTal for cash proceeds net of transaction costs of $14.6 million, resulting in a loss on sale of $5.1 million. 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'. As at September 30, 2021, Gran Tierra holds approximately 137 million common shares representing approximately 17% of PetroTal's issued and outstanding common shares. 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 estimated fair value of the PSUs liability is 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, 2021, and December 31, 2020, was as follows: (Thousands of U.S. Dollars) As at September 30, 2021 As at December 31, 2020 Investment $ 44,116 $ 48,323 Derivative liability $ 14,737 $ 12,050 PSUs and DSUs liability 13,601 4,760 $ 28,338 $ 16,810 The following table presents gains or losses on derivatives and other 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) 2021 2020 2021 2020 Commodity price derivatives loss (gain) $ 2,586 $ (2,206) $ 47,435 $ (12,983) Foreign currency derivatives loss 17 33 105 3,566 Derivative instruments loss (gain) $ 2,603 $ (2,173) $ 47,540 $ (9,417) Unrealized PetroTal investment (gain) loss $ (13,616) $ 1,055 $ (17,477) $ 60,124 Loss on sale of PetroTal shares — — 5,070 — Financial instruments (gain) loss (18) 405 (18) 1,162 Other financial instruments (gain) loss $ (13,634) $ 1,460 $ (12,425) $ 61,286 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, 2021, the carrying amounts of the 6.25% Senior Notes and the 7.75% Senior Notes were $293.5 million and $291.7 million, respectively, which represented the aggregate principal amount less unamortized debt issuance costs, and the fair values were $262.6 million and $260.1 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, 2021, the fair value of the investment and DSUs liability was determined using Level 1 inputs. The fair value of the derivative 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 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 flows to assure it can execute at least a portion of its planned capital spending. At September 30, 2021, 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) Swap Price ($/bbl, Weighted Average) Three-way Collars: 7,000 ICE Brent 47.14 57.14 68.95 n/a Swaps: October 1, to December 31, 2021 3,000 ICE Brent n/a n/a n/a 56.75 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, 2021, 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, 2021 3,000 782 COP 3,500 3,630 (1) At September 30, 2021 foreign exchange rate.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	9 Months Ended
	Sep. 30, 2021
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information The following table provides a reconciliation of cash and cash equivalents and restricted cash and cash equivalents shown as a sum of these amounts in the interim unaudited condensed consolidated statements of cash flows: (Thousands of U.S. Dollars) As at September 30, As at December 31, 2021 2020 2020 2019 Cash and cash equivalents $ 16,600 $ 21,808 $ 14,114 $ 8,817 Restricted cash and cash equivalents - 3,532 3,007 3,409 2,258 $ 20,132 $ 24,815 $ 17,523 $ 11,075 Net changes in assets and liabilities from operating activities were as follows: Nine Months Ended September 30, (Thousands of U.S. Dollars) 2021 2020 Accounts receivable and other long-term assets $ (18,582) $ 31,108 Derivatives (2,427) 694 Inventory (2,920) (2,377) Prepaids 42 (183) Accounts payable and accrued and other long-term liabilities 14,417 (57,621) Taxes receivable and payable 27,426 51,667 Net changes in assets and liabilities from operating activities $ 17,956 $ 23,288 Changes in non-cash investing working capital for the nine months ended September 30, 2021, are comprised of an increase in accounts payable and accrued liabilities of $0.6 million and a decrease in accounts receivable of $0.1 million (nine months ended September 30, 2020, a decrease in accounts payable and accrued liabilities of $69.9 million and a decrease in accounts receivable of $0.3 million). The following table provides additional supplemental cash flow disclosures: Nine Months Ended September 30, (Thousands of U.S. Dollars) 2021 2020 Cash paid for income taxes $ 20,433 $ 11,603 Cash paid for interest $ 37,259 $ 35,408 Non-cash investing activities: Net liabilities related to property, plant and equipment, end of period $ 29,420 $ 7,805

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
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.

Taxes Receivable and Payable (T

Taxes Receivable and Payable (Tables)	9 Months Ended
	Sep. 30, 2021
Tax Receivable Agreement [Abstract]
Schedule of Taxes Receivable Components	The table below shows the break-down of taxes receivable and payable, which are comprised of value added tax ("VAT") and income tax: (Thousands of U.S. Dollars) As at September 30, 2021 As at December 31, 2020 Taxes Receivable Current VAT Receivable $ 31,890 $ 35,977 Income Tax Receivable 15,882 13,948 $ 47,772 $ 49,925 Long-Term VAT Receivable $ — $ 28,485 Income Tax Receivable 14,447 14,150 $ 14,447 $ 42,635 Taxes Payable Current VAT Payable $ 5,938 $ — Total Taxes Receivable net of Taxes Payable $ 56,281 $ 92,560
Schedule of Taxes Receivable Roll Forward	The following table shows the movement of VAT and income tax receivables for the period identified below: (Thousands of U.S. Dollars) Net VAT Receivable Income Tax Receivable Total Net Taxes Receivable Balance, as at December 31, 2020 $ 64,462 $ 28,098 $ 92,560 Collected through direct government refunds (518) (14,228) (14,746) Collected through sales contracts (70,881) — (70,881) Taxes paid (1) 38,278 19,923 58,201 Foreign exchange loss (5,389) (3,464) (8,853) Balance, as at September 30, 2021 $ 25,952 $ 30,329 $ 56,281 (1) VAT is paid on certain goods and services in Colombia at a rate of 19%

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	9 Months Ended
	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	(Thousands of U.S. Dollars) As at September 30, 2021 As at December 31, 2020 Oil and natural gas properties Proved $ 4,236,548 $ 4,106,768 Unproved 158,483 161,763 4,395,031 4,268,531 Other (1) 32,779 32,135 4,427,810 4,300,666 Accumulated depletion and depreciation and impairment (3,433,173) (3,336,184) $ 994,637 $ 964,482 (1) The "other" category includes right-of-use assets for operating and finance leases of $11.7 million, which had a net book value of $2.5 million as at September 30, 2021 (December 31, 2020 - $11.4 million which had a net book value of $4.4 million).

Debt and Debt Issuance Costs (T

Debt and Debt Issuance Costs (Tables)	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Schedule of Debt	The Company's debt at September 30, 2021, and December 31, 2020, was as follows: (Thousands of U.S. Dollars) As at September 30, 2021 As at December 31, 2020 6.25% Senior Notes, due February 2025 $ 300,000 $ 300,000 7.75% Senior Notes, due May 2027 300,000 300,000 Revolving credit facility 150,000 190,000 Unamortized debt issuance costs (15,566) (18,124) Long-term debt 734,434 771,876 Long-term lease obligation (1) 977 2,894 $ 735,411 $ 774,770 (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 $2.9 million as at September 30, 2021 (December 31, 2020 - $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) 2021 2020 2021 2020 Contractual interest and other financing expenses $ 12,701 $ 13,191 $ 38,673 $ 37,430 Amortization of debt issuance costs 907 838 2,682 2,774 $ 13,608 $ 14,029 $ 41,355 $ 40,204

Share Capital (Tables)

Share Capital (Tables)	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Schedule of Common Stock	Shares of Common Stock Balance, December 31, 2020 366,981,556 Shares issued on option exercise 56,898 Balance, September 30, 2021 367,038,454
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, 2021: 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, 2020 23,273,404 4,067,897 15,444,949 1.50 Granted 13,428,840 1,310,122 5,834,014 0.80 Exercised (2,733,209) — (56,898) 0.33 Forfeited (3,492,165) — (1,628,591) 0.90 Expired — — (1,279,641) 3.17 Balance, September 30, 2021 30,476,870 5,378,019 18,313,833 1.22
Schedule of Weighted Average Shares Outstanding	Weighted Average Shares Outstanding Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Weighted average number of common shares outstanding 366,992,802 366,981,556 366,985,646 366,981,556 Shares issuable pursuant to stock options 1,574,305 — — — Shares assumed to be purchased from proceeds of stock options (826,385) — — — Weighted average number of diluted common shares outstanding 367,740,722 366,981,556 366,985,646 366,981,556

COVID-19 Costs (Tables)

COVID-19 Costs (Tables)	9 Months Ended
	Sep. 30, 2021
Unusual or Infrequent Items, or Both [Abstract]
Schedule Cost Incurred due to Catastrophic Events	The COVID-19 pandemic has resulted in additional ongoing 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) 2021 2020 2021 2020 Operating expenses $ 881 $ 1,012 $ 2,743 $ 1,433 Transportation costs 109 96 283 96 Total COVID-19 costs $ 990 $ 1,108 $ 3,026 $ 1,529

Financial Instruments and Fai_2

Financial Instruments and Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2021
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, 2021, and December 31, 2020, was as follows: (Thousands of U.S. Dollars) As at September 30, 2021 As at December 31, 2020 Investment $ 44,116 $ 48,323 Derivative liability $ 14,737 $ 12,050 PSUs and DSUs liability 13,601 4,760 $ 28,338 $ 16,810
Schedule of Gains or Losses on Financial Instruments Recognized	The following table presents gains or losses on derivatives and other 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) 2021 2020 2021 2020 Commodity price derivatives loss (gain) $ 2,586 $ (2,206) $ 47,435 $ (12,983) Foreign currency derivatives loss 17 33 105 3,566 Derivative instruments loss (gain) $ 2,603 $ (2,173) $ 47,540 $ (9,417) Unrealized PetroTal investment (gain) loss $ (13,616) $ 1,055 $ (17,477) $ 60,124 Loss on sale of PetroTal shares — — 5,070 — Financial instruments (gain) loss (18) 405 (18) 1,162 Other financial instruments (gain) loss $ (13,634) $ 1,460 $ (12,425) $ 61,286
Schedule of Commodity Price Derivative Positions and Commodity Foreign Currency Contracts	At September 30, 2021, 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 ($/bbl, Weighted Average) Swap Price ($/bbl, Weighted Average) Three-way Collars: 7,000 ICE Brent 47.14 57.14 68.95 n/a Swaps: October 1, to December 31, 2021 3,000 ICE Brent n/a n/a n/a 56.75
Schedule of Outstanding Foreign Currency Derivative Positions	At September 30, 2021, 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, 2021 3,000 782 COP 3,500 3,630 (1) At September 30, 2021 foreign exchange rate.

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2021
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 shown as a sum of these amounts in the interim unaudited condensed consolidated statements of cash flows: (Thousands of U.S. Dollars) As at September 30, As at December 31, 2021 2020 2020 2019 Cash and cash equivalents $ 16,600 $ 21,808 $ 14,114 $ 8,817 Restricted cash and cash equivalents - 3,532 3,007 3,409 2,258 $ 20,132 $ 24,815 $ 17,523 $ 11,075
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) 2021 2020 Accounts receivable and other long-term assets $ (18,582) $ 31,108 Derivatives (2,427) 694 Inventory (2,920) (2,377) Prepaids 42 (183) Accounts payable and accrued and other long-term liabilities 14,417 (57,621) Taxes receivable and payable 27,426 51,667 Net changes in assets and liabilities from operating activities $ 17,956 $ 23,288
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) 2021 2020 Cash paid for income taxes $ 20,433 $ 11,603 Cash paid for interest $ 37,259 $ 35,408 Non-cash investing activities: Net liabilities related to property, plant and equipment, end of period $ 29,420 $ 7,805

Taxes Receivable and Payable (D

Taxes Receivable and Payable (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Current
VAT Receivable	$ 31,890	$ 35,977
Income Tax Receivable	15,882	13,948
Tax Receivable	47,772	49,925
Long-Term
VAT Receivable	0	28,485
Income Tax Receivable	14,447	14,150
Tax Receivable	14,447	42,635
Current
VAT Payable	5,938	0
Total Taxes Receivable net of Taxes Payable	56,281	$ 92,560
Net VAT Receivable
Beginning balance	64,462
Collected through direct government refunds	(518)
Collected through sales contracts	(70,881)
Taxes paid	38,278
Foreign exchange loss	(5,389)
Ending Balance	25,952
Income Tax Receivable
Beginning balance	28,098
Collected through direct government refunds	(14,228)
Collected through sales contracts	0
Taxes paid	19,923
Foreign exchange loss	(3,464)
Ending balance	30,329
Total Net Taxes Receivable
Beginning balance	92,560
Collected through direct government refunds	(14,746)
Collected through sales contracts	(70,881)
Taxes paid	58,201
Foreign exchange loss	(8,853)
Ending balance	$ 56,281
Colombia
Taxes Receivable [Line Items]
Value added tax, percent	19.00%

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 4,427,810	$ 4,300,666
Accumulated depletion and depreciation and impairment	(3,433,173)	(3,336,184)
Total Property, Plant and Equipment (Note 4)	994,637	964,482
Right-of-use asset, gross	11,700	11,400
Right-of-use asset, net	2,500	4,400
Oil and natural gas properties
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,395,031	4,268,531
Proved
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,236,548	4,106,768
Unproved
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	158,483	161,763
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 32,779	$ 32,135

Impairment (Details)

Impairment (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)$ / bbl	Sep. 30, 2020USD ($)$ / bbl
Property, Plant and Equipment [Line Items]
Impairment of oil and gas properties	$ 0	$ 104,700,000	$ 0	$ 502,900,000
Inventory impairment	0	100,000	0	4,200,000
Goodwill impairment	$ 0	$ 0	$ 0	$ 102,581,000
Crude Oil and NGL
Property, Plant and Equipment [Line Items]
Average Brent price per barrel (in USD per barrel) | $ / bbl			60.12	47.95

Debt and Debt Issuance Costs -

Debt and Debt Issuance Costs - Schedule of Debt (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ (15,566,000)	$ (18,124,000)
Long-term debt	734,434,000	771,876,000
Long-term lease obligation	977,000	2,894,000
Long-term debt excluding current maturity	$ 735,411,000	774,770,000
Senior notes | 6.25% Senior Notes, due February 2025
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, due May 2027
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	150,000,000	190,000,000
Lease obligations | Accounts payable
Debt Instrument [Line Items]
Current portion of lease obligation	$ 2,900,000	$ 3,300,000

Debt and Debt Issuance Costs _2

Debt and Debt Issuance Costs - Narrative (Details) - Revolving credit facility - Revolving credit facility	3 Months Ended	9 Months Ended
	Sep. 30, 2021USD ($)	Sep. 30, 2021USD ($)	Oct. 01, 2021	Jun. 01, 2020
Line of Credit Facility [Line Items]
Borrowing base	$ 215,000,000	$ 215,000,000
Minimum
Line of Credit Facility [Line Items]
Debt to EBITDAX ratio				4
EBITDAX to interest expense, ratio, current quarter	2
Unused capacity, commitment fee percentage		0.73%
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 | Subsequent Event
Line of Credit Facility [Line Items]
EBITDAX to interest expense, ratio			2.5
Maximum
Line of Credit Facility [Line Items]
Senior secured debt to EBITDAX ratio				2.5
Unused capacity, commitment fee percentage		1.23%
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 | Subsequent Event
Line of Credit Facility [Line Items]
Debt to EBITDAX ratio			4
Senior secured debt to EBITDAX ratio			3

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, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Debt Disclosure [Abstract]
Contractual interest and other financing expenses	$ 12,701	$ 13,191	$ 38,673	$ 37,430
Amortization of debt issuance costs	907	838	2,682	2,774
Total interest expense recognized	$ 13,608	$ 14,029	$ 41,355	$ 40,204

Share Capital - Schedule of Com

Share Capital - Schedule of Common Stock (Details)	9 Months Ended
	Sep. 30, 2021shares
Increase (Decrease) in Common Stock
Common shares outstanding, as at beginning of period (in shares)	366,981,556
Shares issued on option exercise (in shares)	56,898
Common shares outstanding, as at period end (in shares)	367,038,454
Shares of Common Stock
Increase (Decrease) in Common Stock
Common shares outstanding, as at beginning of period (in shares)	366,981,556
Shares issued on option exercise (in shares)	56,898
Common shares outstanding, as at period end (in shares)	367,038,454

Share Capital - Schedule of PSU

Share Capital - Schedule of PSU, DSU, RSU and Stock Option Activity (Details)	9 Months Ended
	Sep. 30, 2021$ / sharesshares
Number of Outstanding Stock Options
Beginning Balance (in shares)	15,444,949
Granted (in shares)	5,834,014
Exercised (in shares)	(56,898)
Forfeited (in shares)	(1,628,591)
Expired (in shares)	(1,279,641)
Ending Balance (in shares)	18,313,833
Weighted Average Exercise Price/Stock Option ($)
Beginning balance (in dollars per share) | $ / shares	$ 1.50
Granted (in dollars per share) | $ / shares	0.80
Exercised (in dollars per share) | $ / shares	0.33
Forfeited (in dollars per share) | $ / shares	0.90
Expired (in dollars per share) | $ / shares	3.17
Ending balance (in dollars per share) | $ / shares	$ 1.22
PSUs
Number of Outstanding Share Units
Beginning Balance (in shares)	23,273,404
Granted (in shares)	13,428,840
Exercised (in shares)	(2,733,209)
Forfeited (in shares)	(3,492,165)
Expired (in shares)	0
Ending Balance (in shares)	30,476,870
DSUs
Number of Outstanding Share Units
Beginning Balance (in shares)	4,067,897
Granted (in shares)	1,310,122
Exercised (in shares)	0
Forfeited (in shares)	0
Expired (in shares)	0
Ending Balance (in shares)	5,378,019

Share Capital - Equity Compensa

Share Capital - Equity Compensation Awards (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense (recovery)	$ 1.1	$ 0.1	$ 6.6	$ (0.7)
Unrecognized compensation cost	$ 14.2		$ 14.2		$ 5.9
Weighted average period for recognition			1 year 9 months 18 days
PSUs | Vested on December 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payments for units vested in period			$ 0.6
PSUs | Vested on December 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payments for units vested in period				$ 3.2

Share Capital - Weighted Averag

Share Capital - Weighted Average Shares Outstanding (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Weighted average number of common shares outstanding, basic (in shares)	366,992,802	366,981,556	366,985,646	366,981,556
Shares issuable pursuant to stock options (in shares)	1,574,305	0	0	0
Shares assumed to be purchased from proceeds of stock options (in shares)	(826,385)	0	0	0
Weighted average number of common shares outstanding, diluted (in shares)	367,740,722	366,981,556	366,985,646	366,981,556

Share Capital - Antidilutive Se

Share Capital - Antidilutive Securities (Details)	3 Months Ended
	Sep. 30, 2021shares
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from diluted income (loss) per share calculation (in shares)	16,362,882

Revenue (Details)

Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Concentration Risk [Line Items]
Variable adjustment for transportation, location, quality, and other elements, percentage	16.00%	22.00%	15.00%	27.00%
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, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Unusual or Infrequent Items, or Both [Abstract]
Operating expenses	$ 881	$ 1,012	$ 2,743	$ 1,433
Transportation costs	109	96	283	96
Total COVID-19 costs	$ 990	$ 1,108	$ 3,026	$ 1,529

Taxes (Details)

Taxes (Details)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Income Tax Contingency [Line Items]
Effective tax rate	397.00%	8.00%
PetroTal
Income Tax Contingency [Line Items]
Goodwill, nondeductible amount, percent	50.00%	50.00%
Colombia
Income Tax Contingency [Line Items]
Effective tax rate	31.00%	32.00%

Contingencies (Details)

Contingencies (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Letters of credit and other credit support provided	$ 102.4	$ 100.6

Financial Instruments and Fai_3

Financial Instruments and Fair Value Measurement - Narrative (Details) $ in Thousands, shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)shares	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)shares	Sep. 30, 2020USD ($)	Sep. 30, 2021$ / shares	Dec. 31, 2020USD ($)	Dec. 31, 2020$ / shares
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	$ 44,116		$ 44,116			$ 48,323
Proceeds on disposition of investment			$ 14,632	$ 0
Unrealized PetroTal investment (gain) loss	$ (13,600)	$ 1,100
Senior notes | 6.25% Senior Notes, due February 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	6.25%		6.25%
Senior notes | 7.75% Senior Notes, due May 2027
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	7.75%		7.75%
Fair value | Senior notes | 6.25% Senior Notes, due February 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	$ 262,600		$ 262,600
Fair value | Senior notes | 7.75% Senior Notes, due May 2027
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	260,100		260,100
Carrying amount | Senior notes | 6.25% Senior Notes, due February 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	293,500		293,500
Carrying amount | Senior notes | 7.75% Senior Notes, due May 2027
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	291,700		291,700
PetroTal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	$ 44,100		$ 44,100
Closing share price (in dollars per share) | $ / shares					$ 0.41		$ 0.25
PetroTal | Fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment owned, balance (in shares) | shares	137		137
Investment owned, percent of total shares	17.00%		17.00%
Petro Tal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of shares disposed, percent			44.00%
Number of shares disposed (in shares) | shares			109
Proceeds on disposition of investment			$ 14,600
Loss on disposition of stock			$ 5,100	$ 0

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, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Investment	$ 44,116	$ 48,323
Derivative liability	14,737	12,050
PSU and DSU liability	13,601	4,760
Liabilities, fair value disclosure	$ 28,338	$ 16,810

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, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments loss (gain)	$ 2,603	$ (2,173)	$ 47,540	$ (9,417)
Unrealized PetroTal investment (gain) loss	(13,616)	1,055	(17,477)	60,124
Loss on sale of PetroTal shares	0	0	5,070	0
Financial instruments (gain) loss	(18)	405	(18)	1,162
Other financial instruments (gain) loss	(13,634)	1,460	(12,425)	61,286
Commodity price derivatives loss (gain)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments loss (gain)	2,586	(2,206)	47,435	(12,983)
Foreign currency derivatives loss
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments loss (gain)	$ 17	$ 33	$ 105	$ 3,566

Financial Instruments and Fai_6

Financial Instruments and Fair Value Measurement - Schedule of Commodity Price Derivative Positions and Commodity Foreign Currency Contracts (Details) - Forecast - Commodity Hedge	6 Months Ended
	Dec. 31, 2021$ / bblbbl
Three-way Collars: October 1, to December 31, 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (in barrels of oil per day) | bbl	7,000
Three-way Collars: October 1, to December 31, 2021 | Sold | Put
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Sold Price (Weighted Average) (in dollars per bbl)	47.14
Three-way Collars: October 1, to December 31, 2021 | Sold | Call
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Sold Price (Weighted Average) (in dollars per bbl)	68.95
Three-way Collars: October 1, to December 31, 2021 | Purchased | Put
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Purchased Put (in dollars per barrel)	57.14
Swaps: October 1, to December 31, 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume (in barrels of oil per day) | bbl	3,000
Premium (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, 2021 $ in Thousands, $ in Thousands	Dec. 31, 2021COP ($)$ / collar	Dec. 31, 2021USD ($)$ / collar
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount Hedged	$ 3,000,000	$ 782
Sold | Put
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Floor Price (COP, Weighted Average)	3,500	3,500
Purchased | Call
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cap Price (COP, Weighted Average)	3,630	3,630

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, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents	$ 16,600	$ 14,114	$ 21,808	$ 8,817
Restricted cash and cash equivalents - long-term	3,532	3,409	3,007	2,258
Cash, cash equivalents and restricted cash and cash equivalents	$ 20,132	$ 17,523	$ 24,815	$ 11,075

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, 2021	Sep. 30, 2020
Supplemental Cash Flow Elements [Abstract]
Accounts receivable and other long-term assets	$ (18,582)	$ 31,108
Derivatives	(2,427)	694
Inventory	(2,920)	(2,377)
Prepaids	42	(183)
Accounts payable and accrued and other long-term liabilities	14,417	(57,621)
Taxes receivable and payable	27,426	51,667
Net changes in assets and liabilities from operating activities	17,956	23,288
Increase (decrease) in accounts payable and accrued liabilities	600	(69,900)
Increase (decrease) in accounts receivable	$ (100)	$ (300)

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, 2021	Sep. 30, 2020
Supplemental Cash Flow Elements [Abstract]
Cash paid for income taxes	$ 20,433	$ 11,603
Cash paid for interest	37,259	35,408
Non-cash investing activities:
Net liabilities related to property, plant and equipment, end of period	$ 29,420	$ 7,805