Gran Tierra Energy (GTE) 10-Q 7 May 14 2014 Q1 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	3 Months Ended
	Mar. 31, 2014	1-May-14
Document and Entity Information [Abstract]	'	'
Entity Registrant Name	'GRAN TIERRA ENERGY INC.	'
Entity Central Index Key	'0001273441	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	272,948,937
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations and Retained Earnings (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
REVENUE AND OTHER INCOME	'	'
Oil and natural gas sales	$168,525	$204,780
Interest income	1,154	591
Total revenue and other income	169,679	205,371
EXPENSES	'	'
Operating	28,293	41,015
Depletion, depreciation, accretion and impairment	53,157	58,412
General and administrative	15,204	11,421
Foreign exchange loss (gain)	126	-5,229
Financial instruments gain (Note 9)	-2,409	0
Other loss (Notes 8 and 9)	0	4,400
Total expenses	94,371	110,019
INCOME BEFORE INCOME TAXES	75,308	95,352
Income tax expense (Note 7)	-30,179	-37,439
NET INCOME AND COMPREHENSIVE INCOME	45,129	57,913
RETAINED EARNINGS, BEGINNING OF PERIOD	410,961	284,673
RETAINED EARNINGS, END OF PERIOD	$456,090	$342,586
NET INCOME PER SHARE — BASIC (in dollars per share)	$0.16	$0.21
NET INCOME PER SHARE — DILUTED (in dollars per share)	$0.16	$0.20
WEIGHTED AVERAGE SHARES OUTSTANDING - BASIC (Note 5)	283,235,202	282,138,525
WEIGHTED AVERAGE SHARES OUTSTANDING - DILUTED (Note 5)	288,636,904	285,026,183

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current Assets	'	'
Cash and cash equivalents	$390,953	$428,800
Restricted cash	394	1,478
Accounts receivable	106,517	49,703
Other financial instruments (Note 9)	2,409	0
Inventory (Note 4)	14,407	13,725
Taxes receivable	13,921	9,980
Prepaids	7,025	6,450
Deferred tax assets (Note 7)	770	2,256
Total Current Assets	536,396	512,392
Oil and Gas Properties (using the full cost method of accounting)	'	'
Proved	795,830	794,069
Unproved	489,817	456,001
Total Oil and Gas Properties	1,285,647	1,250,070
Other capital assets	10,059	10,102
Total Property, Plant and Equipment (Note 4)	1,295,706	1,260,172
Other Long-Term Assets	'	'
Restricted cash	2,876	2,300
Deferred tax assets (Note 7)	1,375	1,407
Taxes receivable	14,246	18,535
Other long-term assets	6,815	7,163
Goodwill	102,581	102,581
Total Other Long-Term Assets	127,893	131,986
Total Assets	1,959,995	1,904,550
Current Liabilities	'	'
Accounts payable	51,734	72,400
Accrued liabilities	103,692	89,567
Taxes payable	121,877	102,887
Deferred tax liabilities (Note 7)	1,265	1,193
Asset retirement obligation (Note 6)	518	518
Total Current Liabilities	279,086	266,565
Long-Term Liabilities	'	'
Deferred tax liabilities (Note 7)	169,798	177,082
Asset retirement obligation (Note 6)	22,654	21,455
Other long-term liabilities	10,776	9,540
Total Long-Term Liabilities	203,228	208,077
Contingencies (Note 8)	'	'
Shareholders’ Equity	'	'
Common Stock (Note 5) (272,792,843 and 272,327,810 shares of Common Stock and 10,528,740 and 10,882,440 exchangeable shares, par value $0.001 per share, issued and outstanding as at March 31, 2014, and December 31, 2013, respectively)	10,187	10,187
Additional paid in capital	1,011,404	1,008,760
Retained earnings	456,090	410,961
Total Shareholders’ Equity	1,477,681	1,429,908
Total Liabilities and Shareholders’ Equity	$1,959,995	$1,904,550

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]	'	'
Common shares, par value (in dollars per share)	$0.00	$0.00
Common shares, issued	272,792,843	272,327,810
Common shares, outstanding	272,792,843	272,327,810
Exchangeable shares, issued	10,528,740	10,528,740
Exchangeable shares, outstanding	10,528,740	10,528,740

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Operating Activities	'	'
Net income	$45,129	$57,913
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depletion, depreciation, accretion and impairment	53,157	58,412
Deferred tax recovery (Note 7)	-2,260	-7,450
Stock-based compensation	1,591	2,067
Unrealized foreign exchange gain	-4,178	-6,744
Unrealized financial instrument gain (Note 9)	-2,409	0
Other loss (Notes 8 and 9)	0	4,400
Net change in assets and liabilities from operating activities	'	'
Accounts receivable and other long-term assets	-54,728	-29,387
Inventory	-318	11,643
Prepaids	-575	-258
Accounts payable and accrued and other liabilities	-19,259	-14,731
Taxes receivable and payable	20,014	33,926
Net cash provided by operating activities	36,164	109,791
Investing Activities	'	'
Decrease (increase) in restricted cash	507	-738
Additions to property, plant and equipment	-75,146	-87,378
Net cash used in investing activities	-74,639	-88,116
Financing Activities	'	'
Proceeds from issuance of shares of Common Stock (Note 5)	628	1,611
Net cash provided by financing activities	628	1,611
Net (decrease) increase in cash and cash equivalents	-37,847	23,286
Cash and cash equivalents, beginning of period	428,800	212,624
Cash and cash equivalents, end of period	390,953	235,910
Cash	368,142	230,767
Term deposits	22,811	5,143
Supplemental cash flow disclosures:	'	'
Cash paid for income taxes	7,453	13,103
Non-cash investing activities:	'	'
Net liabilities related to property, plant and equipment, end of period	$87,859	$66,536

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Shareholders' Equity (USD $)	Total	Share Capital [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]
In Thousands, unless otherwise specified
Balance, beginning of period at Dec. 31, 2011	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'
Issue of shares of Common Stock (Note 5)	'	$2,201	'	'
Exercise of stock options (Note 5)	'	'	1,570	'
Stock-based compensation (Note 5)	'	'	8,418	'
Net income	'	'	'	126,288
Balance, end of period at Dec. 31, 2012	'	7,986	998,772	284,673
Balance, beginning of period at Dec. 31, 2013	1,429,908	10,187	1,008,760	410,961
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'
Issue of shares of Common Stock (Note 5)	'	0	'	'
Exercise of stock options (Note 5)	'	'	628	'
Stock-based compensation (Note 5)	'	'	2,016	'
Net income	45,129	'	'	45,129
Balance, end of period at Mar. 31, 2014	$1,477,681	$10,187	$1,011,404	$456,090

Description_of_Business

Description of Business	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Description of Business	'
	Description of Business
	Gran Tierra Energy Inc., a Nevada corporation (the “Company” or “Gran Tierra”), is a publicly traded oil and gas company engaged in the acquisition, exploration, development and production of oil and natural gas properties. The Company’s principal business activities are in Colombia, Argentina, Peru and Brazil.

Significant_Accounting_Policie

Significant Accounting Policies	3 Months Ended
	Mar. 31, 2014
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, 2013, included in the Company’s 2013 Annual Report on Form 10-K, filed with the Securities and Exchange Commission (“SEC”) on February 26, 2014.
	The Company’s significant accounting policies are described in Note 2 of the consolidated financial statements which are included in the Company’s 2013 Annual Report on Form 10-K and are the same policies followed in these interim unaudited condensed consolidated financial statements, except as disclosed below. The Company has evaluated all subsequent events through to the date these interim unaudited condensed consolidated financial statements were issued.
	Foreign Currency Derivatives
	In February 2014, the Company purchased Colombian peso non-deliverable forward contracts for purposes of fixing the exchange rate at which it will purchase Colombian pesos to settle its income tax installment payments due in April and June 2014 (Note 9). The Company does not intend to issue or hold derivative financial instruments for speculative trading purposes.
	The Company records derivative instruments on the balance sheet as either an asset or liability measured at fair value. The accounting for changes in the fair value of a derivative instrument depends on the intended use of the derivative and the resulting designation, which is established at the inception of a derivative. Generally because of the short-term nature of the contracts and their limited use, the Company does not apply hedge accounting, and changes in the fair value of those contracts are reflected in net income as financial instrument gains or losses in the condensed consolidated statement of operations. Cash settlements of the Company's derivative arrangements are classified as operating cash flows.
	The fair value of foreign currency derivatives is based on the maturity value of the foreign exchange non-deliverable forward contracts, using applicable forward exchange rates. The most significant variable to the cash flow calculations is the estimation of forward foreign exchange rates. The resulting net future cash inflows or outflows at maturity of the contracts are the net value of the contract.
	Recently Adopted Accounting Pronouncements
	Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is fixed at the Reporting Date
	In February 2013, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2013- 04, “Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is fixed at the Reporting Date”. The ASU provides guidance for the recognition, measurement, and disclosure of obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date. Examples of obligations within the scope of this update include debt arrangements, other contractual obligations, and settled litigation and judicial rulings. The ASU was effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The implementation of this update did not materially impact the Company’s consolidated financial position, results of operations, cash flows or disclosure.
	Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists
	In July 2013, the FASB issued ASU 2013-11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists". The ASU provides guidance on the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The ASU was effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The implementation of this update did not materially impact the Company’s consolidated financial position, results of operations, cash flows, or disclosure.

Segment_and_Geographic_Reporti

Segment and Geographic Reporting	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segment and Geographic Reporting	'
	Segment and Geographic Reporting
	The Company is primarily engaged in the exploration and production of oil and natural gas. The Company’s reportable segments are Colombia, Argentina, Peru and Brazil based on geographic organization. The level of activity in Brazil was not significant at March 31, 2014, or December 31, 2013; however, the Company has separately disclosed its results of operations in Brazil as a reportable segment. The All Other category represents the Company’s corporate activities. The Company evaluates reportable segment performance based on income or loss before income taxes.
	The following tables present information on the Company’s reportable segments and other activities:
		Three Months Ended March 31, 2014
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Argentina			Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	144,935	$	17,420		$	—		$	6,170		$	—		$	168,525
	Interest income	137		404			—			425			188			1,154
	Depletion, depreciation, accretion and impairment	41,250		8,893			208			2,579			227			53,157
	Depletion, depreciation, accretion and impairment - per unit of production	25.44		32.23			—			38.89			—			27.07
	Income (loss) before income taxes	86,011		(4,152		)	(2,058		)	1,950			(6,443		)	75,308
	Segment capital expenditures	50,543		6,536			20,893			10,366			299			88,637
		Three Months Ended March 31, 2013
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Argentina			Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	180,003	$	18,540		$	—		$	6,237		$	—		$	204,780
	Interest income	161		243			14			9			164			591
	Depletion, depreciation, accretion and impairment	45,956		7,950			62			4,171			273			58,412
	Depletion, depreciation, accretion and impairment - per unit of production	26.32		26.68			—			65.34			—			27.71
	Income (loss) before income taxes	101,668		(1,636		)	(1,227		)	(439		)	(3,014		)	95,352
	Segment capital expenditures	30,407		4,805			29,247			14,539			11			79,009
	The Company’s revenues are derived principally from uncollateralized sales to customers in the oil and natural gas industry. The concentration of credit risk in a single industry affects the Company’s overall exposure to credit risk because customers may be similarly affected by changes in economic and other conditions.
	In the three months ended March 31, 2014, the Company had two significant customers in Colombia: Ecopetrol S.A. ("Ecopetrol") and one other customer, which accounted for 43% and 37%, respectively, of the Company's consolidated oil and natural gas sales. In the three months ended March 31, 2013, the Company had three significant customers in Colombia, Ecopetrol and two other customers, which accounted for 54%, 21% and 11%, respectively, of the Company's consolidated oil and natural gas sales.
		As at March 31, 2014
	(Thousands of U.S. Dollars)	Colombia		Argentina			Peru			Brazil			All Other			Total
	Property, plant and equipment	$	859,500	$	92,103		$	199,216		$	141,773		$	3,114		$	1,295,706
	Goodwill	102,581		—			—			—			—			102,581
	All other assets	262,269		35,646			27,850			24,336			211,607			561,708
	Total Assets	$	1,224,350	$	127,749		$	227,066		$	166,109		$	214,721		$	1,959,995
		As at December 31, 2013
	(Thousands of U.S. Dollars)	Colombia		Argentina			Peru			Brazil			All Other			Total
	Property, plant and equipment	$	850,359	$	94,366		$	178,531		$	133,874		$	3,042		$	1,260,172
	Goodwill	102,581		—			—			—			—			102,581
	All other assets	233,336		39,209			24,240			24,477			220,535			541,797
	Total Assets	$	1,186,276	$	133,575		$	202,771		$	158,351		$	223,577		$	1,904,550

Property_Plant_and_Equipment_a

Property, Plant and Equipment and Inventory	3 Months Ended
	Mar. 31, 2014
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment and Inventory	'
	Property, Plant and Equipment and Inventory
	Property, Plant and Equipment
		As at March 31, 2014							As at December 31, 2013
	(Thousands of U.S. Dollars)	Cost		Accumulated			Net book value		Cost		Accumulated			Net book value
				depletion,							depletion,
				depreciation							depreciation
				and							and
				impairment							impairment
	Oil and natural gas properties
	Proved	$	1,853,547	$	(1,057,717	)	$	795,830	$	1,799,544	$	(1,005,475	)	$	794,069
	Unproved	489,817		—			489,817		456,001		—			456,001
		2,343,364		(1,057,717		)	1,285,647		2,255,545		(1,005,475		)	1,250,070
	Furniture and fixtures and leasehold improvements	9,182		(6,989		)	2,193		8,919		(6,568		)	2,351
	Computer equipment	15,297		(8,019		)	7,278		14,786		(7,605		)	7,181
	Automobiles	1,425		(837		)	588		1,381		(811		)	570
	Total Property, Plant and Equipment	$	2,369,268	$	(1,073,562	)	$	1,295,706	$	2,280,631	$	(1,020,459	)	$	1,260,172
	Depletion and depreciation expense on property, plant and equipment for the three months ended March 31, 2014, was $53.1 million (three months ended March 31, 2013 - $54.6 million). A portion of depletion and depreciation expense was recorded as inventory in each period and adjusted for inventory changes.
	In Brazil, the exploration phase of the concession agreements on Blocks REC-T-129, REC-T-142 and REC-T-155 were each due to expire on November 24, 2013, and the exploration phase of the concession agreement on Block REC-T-224 was due to expire on December 11, 2013; however, under the concession agreements the Company was able and did submit applications to the Agência Nacional de Petróleo, Gás Natural e Biocombustíveis ("ANP") for extensions or suspensions of the exploration phases of these blocks. The Company has not yet received a decision from the ANP regarding these extension or suspension applications. At March 31, 2014, unproved properties included $71.9 million relating to exploration expenditures on these four blocks. Management assessed these blocks for impairment at March 31, 2014, and concluded no impairment had occurred.
	In Argentina, Rio Negro Province has enacted legislation that changes the royalty regime associated with concession agreement extensions. The Company is negotiating concession agreement extensions and royalty rates for its Puesto Morales, Puesto Morales Este, Rinconada Norte and Rinconada Sur Blocks and expects that royalty rates in Rio Negro Province will likely increase and a bonus payment, not determinable at this time, may be payable for the concession agreement extensions.
	Unproved oil and natural gas properties consist of exploration lands held in Colombia, Argentina, Peru and Brazil. As at March 31, 2014, the Company had $184.0 million (December 31, 2013 - $176.1 million) of unproved assets in Colombia, $17.7 million (December 31, 2013 - $18.2 million) of unproved assets in Argentina, $198.1 million (December 31, 2013 - $177.5 million) of unproved assets in Peru, and $90.0 million (December 31, 2013 - $84.2 million) of unproved assets in Brazil for a total of $489.8 million (December 31, 2013 - $456.0 million). These properties are being held for their exploration value and are not being depleted pending determination of the existence of proved reserves. Gran Tierra will continue to assess the unproved properties over the next several years as proved reserves are established and as exploration warrants whether or not future areas will be developed.
	Inventory
	At March 31, 2014, oil and supplies inventories were $12.1 million and $2.3 million, respectively (December 31, 2013 - $11.7 million and $2.0 million, respectively).

Share_Capital

Share Capital	3 Months Ended
	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Share Capital	'
	Share Capital
	The Company’s authorized share capital consists of 595,000,002 shares of capital stock, of which 570 million are designated as Common Stock, par value $0.001 per share, 25 million are designated as Preferred Stock, par value $0.001 per share, and two shares are designated as special voting stock, par value $0.001 per share.
	As at March 31, 2014, outstanding share capital consists of 272,792,843 shares of Common Stock of the Company, 5,994,613 exchangeable shares of Gran Tierra Exchangeco Inc., (the "Exchangeco exchangeable shares") and 4,534,127 exchangeable shares of Gran Tierra Goldstrike Inc. (the "Goldstrike exchangeable shares"). The redemption date for the Exchangeco exchangeable shares and the Goldstrike exchangeable shares is a date to be established by the applicable Board of Directors. During the three months ended March 31, 2014, 111,333 shares of Common Stock were issued upon the exercise of stock options and 353,700 shares of Common Stock were issued upon the exchange of the Exchangeco exchangeable shares.
	The holders of shares of Common Stock are entitled to one vote for each share on all matters submitted to a stockholder vote and are entitled to share in all dividends that the Company’s Board of Directors, in its discretion, declares from legally available funds. The holders of Common Stock have no pre-emptive rights, no conversion rights, and there are no redemption provisions applicable to the shares. Holders of exchangeable shares have substantially the same rights as holders of shares of Common Stock. Each exchangeable share is exchangeable into one share of Common Stock of the Company.
	Restricted Stock Units and Stock Options
	The Company grants time-vested restricted stock units ("RSUs") to certain officers, employees and consultants. Additionally, the Company grants options to purchase shares of Common Stock to certain directors, officers, employees and consultants. The following table provides information about RSU and stock option activity for the three months ended March 31, 2014:
		RSUs			Options
		Number of Outstanding Share Units			Number of Outstanding Options			Weighted Average Exercise Price $/Option
	Balance, December 31, 2013	922,045			15,668,458			5.41
	Granted	835,490			2,237,630			7.09
	Exercised	(292,608	)		(111,333	)		(5.64	)
	Forfeited	(17,984	)		(84,156	)		(6.57	)
	Expired	—			(67,668	)		(6.81	)
	Balance, March 31, 2014	1,446,943			17,642,931			5.61
	For the three months ended March 31, 2014, 111,333 shares of Common Stock were issued for cash proceeds of $0.6 million upon the exercise of 111,333 stock options (three months ended March 31, 2013 - $1.6 million).
	The weighted average grant date fair value for options granted in the three months ended March 31, 2014, was $2.52 (three months ended March 31, 2013 - $3.33).
	The amounts recognized for stock-based compensation were as follows:
	(Thousands of U.S. Dollars)		Three Months Ended March 31,
			2014				2013
	Compensation costs for stock options		$	2,016			$	2,231
	Compensation costs for RSUs		1,244				—
			3,260				2,231
	Less: stock-based compensation costs capitalized		(783		)		(182		)
	Stock-based compensation costs expensed		$	2,477			$	2,049
	Of the total compensation expense for the three months ended March 31, 2014, $2.2 million (three months ended March 31, 2013 – $1.8 million) was recorded in general and administrative expenses and $0.3 million (three months ended March 31, 2013 – $0.2 million) was recorded in operating expenses.
	At March 31, 2014, there was $16.1 million (December 31, 2013 - $8.1 million) of unrecognized compensation cost related to unvested stock options and RSUs which is expected to be recognized over a weighted average period of 2.2 years.
	Net income per share
	Basic net income per share is calculated by dividing net income attributable to common shareholders by the weighted average number of shares of Common Stock and exchangeable shares issued and outstanding during each period. Diluted net income per share is calculated by adjusting the weighted average number of shares of Common Stock and exchangeable shares outstanding for the dilutive effect, if any, of share equivalents. The Company uses the treasury stock method to determine the dilutive effect. This method assumes that all Common Stock equivalents have been exercised at the beginning of the period (or at the time of issuance, if later), and that the funds obtained thereby were used to purchase shares of Common Stock of the Company at the volume weighted average trading price of shares of Common Stock during the period.
			Three Months Ended March 31,
			2014			2013
	Weighted average number of common and exchangeable shares outstanding		283,235,202			282,138,525
	Shares issuable pursuant to stock options		14,553,754			5,482,456
	Shares assumed to be purchased from proceeds of stock options		(9,152,052	)		(2,594,798	)
	Weighted average number of diluted common and exchangeable shares outstanding		288,636,904			285,026,183
	For the three months ended March 31, 2014, 3,175,152 options (three months ended March 31, 2013 - 9,392,605 options) were excluded from the diluted income per share calculation as the options were anti-dilutive.

Asset_Retirement_Obligation

Asset Retirement Obligation	3 Months Ended
	Mar. 31, 2014
Asset Retirement Obligation [Abstract]	'
Asset Retirement Obligation	'
	Asset Retirement Obligation
	Changes in the carrying amounts of the asset retirement obligation associated with the Company’s oil and natural gas properties were as follows:
		Three Months Ended			Year Ended
	(Thousands of U.S. Dollars)	March 31, 2014			December 31, 2013
	Balance, beginning of year	$	21,973		$	18,292
	Settlements	—			(2,068		)
	Liability incurred	786			2,623
	Foreign exchange	(5		)	(25		)
	Accretion	418			1,279
	Revisions in estimated liability	—			1,872
	Balance, end of period	$	23,172		$	21,973
	Asset retirement obligation - current	$	518		$	518
	Asset retirement obligation - long-term	22,654			21,455
	Balance, end of period	$	23,172		$	21,973
	Revisions to estimated liabilities relate primarily to changes in estimates of asset retirement costs and include, but are not limited to, revisions of estimated inflation rates, changes in property lives and the expected timing of settling the asset retirement obligation. At March 31, 2014, the fair value of assets that are legally restricted for purposes of settling the asset retirement obligation was $2.0 million (December 31, 2013 - $1.9 million). These assets are included in restricted cash on the Company's balance sheet.

Taxes

Taxes	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Taxes	'
	Taxes
	The income tax expense reported differs from the amount computed by applying the U.S. statutory rate to income before income taxes for the following reasons:
		Three Months Ended March 31,
	(Thousands of U.S. Dollars)	2014			2013
	Income (loss) before income taxes
	United States	$	(5,078	)	$	(2,091	)
	Foreign	80,386			97,443
		75,308			95,352
		35		%	35		%
	Income tax expense expected	26,358			33,373
	Foreign currency translation adjustments	4,160			(1,878		)
	Impact of foreign taxes	(1,093		)	(224		)
	Stock-based compensation	760			686
	(Decrease) increase in valuation allowance	(2,439		)	1,844
	Branch and other foreign loss pick-up	254			(827		)
	Non-deductible third party royalty in Colombia	2,223			3,547
	Other permanent differences	(44		)	918
	Total income tax expense	$	30,179		$	37,439
	Current income tax expense
	United States	$	357		$	306
	Foreign	32,082			44,583
		32,439			44,889
	Deferred income tax recovery
	United States	—			—
	Foreign	(2,260		)	(7,450		)
		(2,260		)	(7,450		)
	Total income tax expense	$	30,179		$	37,439
		As at
	(Thousands of U.S. Dollars)	March 31, 2014			31-Dec-13
	Deferred Tax Assets
	Tax benefit of operating loss carryforwards	$	45,630		$	47,154
	Tax basis in excess of book basis	57,340			59,168
	Foreign tax credits and other accruals	35,619			34,894
	Tax benefit of capital loss carryforwards	4,838			4,769
	Deferred tax assets before valuation allowance	143,427			145,985
	Valuation allowance	(141,282		)	(142,322		)
		$	2,145		$	3,663
	Deferred tax assets - current	$	770		$	2,256
	Deferred tax assets - long-term	1,375			1,407
		2,145			3,663
	Deferred tax liabilities - current	(1,265		)	(1,193		)
	Deferred tax liabilities - long-term	(169,798		)	(177,082		)
		(171,063		)	(178,275		)
	Net Deferred Tax Liabilities	$	(168,918	)	$	(174,612	)
	As at March 31, 2014, the Company had operating loss carryforwards of $206.8 million (December 31, 2013 - $215.4 million) and capital loss carryforwards of $32.8 million (December 31, 2013 – $32.6 million) before valuation allowance. Of these operating loss carryforwards and capital loss carryforwards, $203.5 million (December 31, 2013 - $213.8 million) were losses generated by the foreign subsidiaries of the Company. In certain jurisdictions, the operating loss carryforwards expire between 2014 and 2033 and the capital loss carryforwards expire between 2016 and 2017, while certain other jurisdictions allow operating losses to be carried forward indefinitely.
	As at March 31, 2014, the total amount of Gran Tierra’s unrecognized tax benefit was $22.5 million (December 31, 2013 - $22.1 million), approximately $12.8 million of which, if recognized, would affect the Company’s effective tax rate. To the extent interest and penalties may be assessed by taxing authorities on any underpayment of income tax, such amounts have been accrued and are classified as a component of income taxes in the consolidated statement of operations.
	Changes in the Company's unrecognized tax benefit are as follows:
		Three Months Ended March 31,
		2014			2013
	(Thousands of U.S. Dollars)
	Unrecognized tax benefit at beginning of period	$	22,100		$	21,800
	Decreases for positions relating to prior year	(1,100		)	—
	Additions to tax position related to the current year	1,500			—
	Unrecognized tax benefit at end of period	$	22,500		$	21,800
	The Company and its subsidiaries file income tax returns in U.S. federal and state jurisdictions and certain other foreign jurisdictions. The Company is potentially subject to income tax examinations for the tax years 2006 through 2013 in certain jurisdictions. The Company does not anticipate any material changes to the unrecognized tax benefit disclosed above within the next twelve months.
	At March 31, 2014, and December 31, 2013, accounts payable included the remaining unpaid balance of equity tax liability,
	a Colombian tax of 6% on a legislated measure calculated based on the Company’s Colombian segment’s balance sheet equity for tax purposes at January 1, 2011. The tax is payable in eight semi-annual installments over four years, but was expensed in the first quarter of 2011 at the commencement of the four-year period. The equity tax liability also partially related to an equity tax liability assumed upon an acquisition in 2011.

Contingencies

Contingencies	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Contingencies	'
	Contingencies
	Gran Tierra Energy Colombia, Ltd. and Petrolifera Petroleum (Colombia) Ltd (collectively “GTEC”) and Ecopetrol, the contracting parties of the Guayuyaco Association Contract, are engaged in a dispute regarding the interpretation of the procedure for allocation of oil produced and sold during the long-term test of the Guayuyaco-1 and Guayuyaco-2 wells, prior to GTEC's purchase of the companies originally involved in the dispute. There has been no agreement between the parties, and Ecopetrol filed a lawsuit in the Contravention Administrative Tribunal in the District of Cauca (the "Tribunal") regarding this matter. During the first quarter of 2013, the Tribunal ruled in favor of Ecopetrol and awarded Ecopetrol 44,025 bbl of oil. GTEC has filed an appeal of the ruling to the Supreme Administrative Court (Consejo de Estado) in a second instance procedure. During the three months ended March 31, 2013, based on market oil prices in Colombia, Gran Tierra accrued $4.4 million in the condensed consolidated financial statements in relation to this dispute (Note 9).
	Gran Tierra’s production from the Costayaco Exploitation Area is subject to an additional royalty (the "HPR royalty"), which applies when cumulative gross production from an Exploitation Area is greater than five MMbbl. The HPR royalty is calculated on the difference between a trigger price defined in the Chaza Block exploration and production contract (the "Chaza Contract") and the sales price. The Agencia Nacional de Hidrocarburos (National Hydrocarbons Agency) (“ANH”) has interpreted the Chaza Contract as requiring that the HPR royalty must be paid with respect to all production from the Moqueta Exploitation Area and initiated a noncompliance procedure under the Chaza Contract, which was contested by Gran Tierra because the Moqueta Exploitation Area and the Costayaco Exploitation Area are separate Exploitation Areas. ANH did not proceed with that noncompliance procedure. Gran Tierra also believes that the evidence shows that the Costayaco and Moqueta fields are two clearly separate and independent hydrocarbon accumulations. Therefore, it is Gran Tierra’s view that, pursuant to the terms of the Chaza Contract, the HPR royalty is only to be paid with respect to production from the Moqueta Exploitation Area when the accumulated oil production from that Exploitation Area exceeds five MMbbl. Discussions with the ANH have not resolved this issue and Gran Tierra has initiated the dispute resolution process under the Chaza Contract and filed an arbitration claim seeking a decision that the HPR royalty is not payable until production from the Moqueta Exploitation Area exceeds five MMbbl. The ANH filed a response to the claim seeking a declaration that its interpretation is correct and a counterclaim seeking, amongst other remedies, declarations that Gran Tierra breached the Chaza Contract by not paying the disputed HPR royalty, that the amount of the alleged HPR royalty that is payable, and that the Chaza Contract be terminated. Gran Tierra filed a response to the ANH's counterclaim and filed its comments on the ANH's responses to Gran Tierra's claim. The ANH filed an amended counterclaim and Gran Tierra filed a response to the ANH's amended counterclaim. As at March 31, 2014, total cumulative production from the Moqueta Exploitation Area was 2.7 MMbbl. The estimated compensation which would be payable on cumulative production to that date if the ANH is successful in the arbitration is $44.9 million. At this time no amount has been accrued in the condensed consolidated financial statements nor deducted from the Company's reserves for the disputed HPR royalty as Gran Tierra does not consider it probable that a loss will be incurred.
	Additionally, the ANH and Gran Tierra are engaged in discussions regarding the interpretation of whether certain transportation and related costs are eligible to be deducted in the calculation of the HPR royalty. Discussions with the ANH are ongoing. Based on the Company's understanding of the ANH's position, the estimated compensation which would be payable if the ANH’s interpretation is correct could be up to $31.7 million as at March 31, 2014. At this time no amount has been accrued in the financial statements as Gran Tierra does not consider it probable that a loss will be incurred.
	In addition to the above, Gran Tierra has several other lawsuits and claims pending. Although the outcome of these other 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
	At March 31, 2014, the Company had provided promissory notes totaling $52.5 million (December 31, 2013 - $52.5 million) as security for letters of credit relating to work commitment guarantees contained in exploration contracts and other capital or operating requirements.

Financial_Instruments_Fair_Val

Financial Instruments, Fair Value Measurements and Credit Risk	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Financial Instruments, Fair Value Measurements and Credit Risk	'
	Financial Instruments, Fair Value Measurements and Credit Risk
	At March 31, 2014, the Company’s financial instruments recognized in the balance sheet consist of cash and cash equivalents, restricted cash, accounts receivable, accounts payable, accrued liabilities, foreign currency derivatives included in current assets and contingent consideration and contingent liability included in other long-term liabilities.
	The fair value of long-term restricted cash approximates its carrying value because interest rates are variable and reflective of market rates.
	The fair value of foreign currency derivatives is based on the maturity value of foreign exchange non-deliverable forward contracts using applicable forward exchange rates. The most significant variable to the cash flow calculations is the estimation of forward foreign exchange rates. The resulting future cash inflows or outflows at maturity of the contracts are the net value of the contract.
	Contingent consideration, which relates to the acquisition of the remaining 30% working interest in certain properties in Brazil, was recorded on the balance sheet at the acquisition date fair value based on the consideration expected to be transferred and discounted back to present value by applying an appropriate discount rate that reflected the risk factors associated with the payment streams. The discount rate used was determined at the time of measurement in accordance with accepted valuation methods.
	The fair value of the contingent liability which relates to a dispute with Ecopetrol (Note 8) was estimated based on the fair value of the amount awarded using market oil prices in Colombia.
	The fair value of the foreign currency derivatives, contingent consideration and contingent liability are being remeasured at the estimated fair value at each reporting period with the change in fair value recognized as financial instruments gains or losses in net income. The fair value of the foreign currency derivatives, contingent consideration and the contingent liability at March 31, 2014, and December 31, 2013, were as follows:
		As at
	(Thousands of U.S. Dollars)	31-Mar-14			31-Dec-13
	Foreign currency derivative asset	$	2,409		$	—
	Contingent consideration	$	1,061		$	1,061
	Contingent liability (Note 8)	$	4,400		$	4,400
	The following table presents gains or losses on financial instruments recognized in the accompanying condensed consolidated statements of operations:
	(Thousands of U.S. Dollars)	Three Months Ended March 31,
		2014			2013
	Foreign currency derivative gains	$	2,409		$	—
	These gains are presented as financial instrument gain in the condensed consolidated statements of operations and cash flows.
	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 March 31, 2014, and December 31, 2013, the fair value of the contingent liability which relates to a dispute with Ecopetrol (Note 8) was determined using Level 1 inputs and the fair value of the contingent consideration payable in connection with the Brazil acquisition was determined using Level 3 inputs. At March 31, 2014, the fair value of the foreign currency derivatives was determined using Level 2 inputs. The disclosure in the paragraph above regarding the fair value of cash and restricted cash is based on Level 1 inputs.
	The Company’s non-recurring fair value measurements include asset retirement obligation. 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. The significant level 3 inputs used to calculate such liabilities include estimates of costs to be incurred, the Company’s credit-adjusted risk-free interest rate, inflation rates and estimated dates of abandonment. Accretion expense is recognized over time as the discounted liabilities are accreted to their expected settlement value, while the asset retirement cost is amortized over the estimated productive life of the related assets.
	Credit risk arises from the potential that the Company may incur a loss if a counterparty to a financial instrument fails to meet its obligation in accordance with agreed terms. The Company’s financial instruments that are exposed to concentrations of credit risk consist primarily of cash, accounts receivables and foreign currency derivatives. The carrying value of cash, accounts receivable and foreign currency derivatives reflects management’s assessment of credit risk.
	At March 31, 2014, cash and cash equivalents and restricted cash included balances in savings and checking accounts, as well as term deposits and certificates of deposit, placed primarily with financial institutions with strong investment grade ratings or governments, or the equivalent in the Company’s operating areas. In February 2014, the Company purchased non-deliverable forward contracts for purposes of fixing the exchange rate at which it will purchase Colombian pesos to settle its income tax installment payments due in April and June 2014.With the exception of these foreign currency derivatives, any foreign currency transactions are conducted on a spot basis with major financial institutions in the Company’s operating areas.
	At March 31, 2014, the Company had the following open foreign currency derivative position:
	Forward contracts
	Currency	Contract Type	Notional (Billions of Colombian Pesos)	Weighted Average Fixed Rate Received (Colombian Pesos - U.S. Dollars)		Expiration
	Colombian pesos	Buy	109.3	2,037		Apr-14
	Colombian pesos	Buy	40.5	2,045		Jun-14
			149.8
	Most of the Company’s accounts receivable relate to uncollateralized sales to customers in the oil and natural gas industry and are exposed to typical industry credit risks. The concentration of revenues in a single industry affects the Company’s overall exposure to credit risk because customers may be similarly affected by changes in economic and other conditions. The Company manages this credit risk by entering into sales contracts with only credit worthy entities and reviewing its exposure to individual entities on a regular basis. For the three months ended March 31, 2014, the Company had two customers which were significant to the Colombian segment, three customers which were significant to the Argentina segment and one customer which was significant to the Brazilian segment.
	To reduce the concentration of exposure to any individual counterparty, the Company utilizes a group of investment-grade rated counterparties, primarily financial institutions, for its derivative transactions. The Company monitors counterparty creditworthiness on an ongoing basis; however, it cannot predict sudden changes in counterparties’ creditworthiness. In addition, even if such changes are not sudden, the Company may be limited in its ability to mitigate an increase in counterparty credit risk. Should one of these counterparties not perform, the Company may not realize the benefit of some of its foreign currency derivative instruments.
	For the three months ended March 31, 2014, 85% (three months ended March 31, 2013 - 88%) of the Company's revenue and other income was generated in Colombia.
	The Argentina government has imposed a number of monetary and currency exchange control measures that include restrictions on the free disposition of funds deposited with banks and tight restrictions on transferring funds abroad, with certain exceptions for transfers related to foreign trade and other authorized transactions approved by the Argentina Central Bank. The Argentina Central Bank may require prior authorization and may or may not grant such authorization for Gran Tierra's Argentina subsidiaries to make dividends or loan payments to the Company. At March 31, 2014, $15.1 million, or 4%, of the Company's cash and cash equivalents was deposited with banks in Argentina in Argentina pesos. The Company expects to use these funds for the Argentina work program and operations in 2014 and is exposed to foreign exchange gains and losses on its net monetary position.
	Additionally, unrealized foreign exchange gains and losses result from fluctuation of the U.S. dollar to the Colombian peso due to Gran Tierra’s current and deferred tax liabilities, which are monetary liabilities mainly denominated in the local currency of the Colombian operations. As a result, foreign exchange gains and losses must be calculated on conversion to the U.S. dollar functional currency. A strengthening in the Colombian peso against the U.S. dollar results in foreign exchange losses, estimated at $87,000 for each one peso decrease in the exchange rate of the Colombian peso to one U.S. dollar.
	In Colombia, the company receives 100% of its revenues in U.S. dollars and the majority of its capital expenditures are in U.S. dollars or are based on U.S. dollar prices. In Argentina and Brazil, prices for oil are in U.S. dollars, but revenues are received in local currency translated according to current exchange rates. The majority of the Company's capital expenditures within Argentina and Brazil are based on U.S. dollar prices, but are paid in local currency translated according to current exchange rates. In Peru, capital expenditures are based on U.S. dollar prices and may be paid in local currency or U.S. dollars.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Foreign Currency Derivatives	'
	Foreign Currency Derivatives
	In February 2014, the Company purchased Colombian peso non-deliverable forward contracts for purposes of fixing the exchange rate at which it will purchase Colombian pesos to settle its income tax installment payments due in April and June 2014 (Note 9). The Company does not intend to issue or hold derivative financial instruments for speculative trading purposes.
	The Company records derivative instruments on the balance sheet as either an asset or liability measured at fair value. The accounting for changes in the fair value of a derivative instrument depends on the intended use of the derivative and the resulting designation, which is established at the inception of a derivative. Generally because of the short-term nature of the contracts and their limited use, the Company does not apply hedge accounting, and changes in the fair value of those contracts are reflected in net income as financial instrument gains or losses in the condensed consolidated statement of operations. Cash settlements of the Company's derivative arrangements are classified as operating cash flows.
	The fair value of foreign currency derivatives is based on the maturity value of the foreign exchange non-deliverable forward contracts, using applicable forward exchange rates. The most significant variable to the cash flow calculations is the estimation of forward foreign exchange rates. The resulting net future cash inflows or outflows at maturity of the contracts are the net value of the contract.
Recently Issued Accounting Pronouncements	'
	Recently Adopted Accounting Pronouncements
	Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is fixed at the Reporting Date
	In February 2013, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2013- 04, “Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is fixed at the Reporting Date”. The ASU provides guidance for the recognition, measurement, and disclosure of obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date. Examples of obligations within the scope of this update include debt arrangements, other contractual obligations, and settled litigation and judicial rulings. The ASU was effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The implementation of this update did not materially impact the Company’s consolidated financial position, results of operations, cash flows or disclosure.
	Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists
	In July 2013, the FASB issued ASU 2013-11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists". The ASU provides guidance on the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The ASU was effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The implementation of this update did not materially impact the Company’s consolidated financial position, results of operations, cash flows, or disclosure.

Segment_and_Geographic_Reporti1

Segment and Geographic Reporting (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Reportable Geographic Segments	'
	The following tables present information on the Company’s reportable segments and other activities:
		Three Months Ended March 31, 2014
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Argentina			Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	144,935	$	17,420		$	—		$	6,170		$	—		$	168,525
	Interest income	137		404			—			425			188			1,154
	Depletion, depreciation, accretion and impairment	41,250		8,893			208			2,579			227			53,157
	Depletion, depreciation, accretion and impairment - per unit of production	25.44		32.23			—			38.89			—			27.07
	Income (loss) before income taxes	86,011		(4,152		)	(2,058		)	1,950			(6,443		)	75,308
	Segment capital expenditures	50,543		6,536			20,893			10,366			299			88,637
		Three Months Ended March 31, 2013
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Argentina			Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	180,003	$	18,540		$	—		$	6,237		$	—		$	204,780
	Interest income	161		243			14			9			164			591
	Depletion, depreciation, accretion and impairment	45,956		7,950			62			4,171			273			58,412
	Depletion, depreciation, accretion and impairment - per unit of production	26.32		26.68			—			65.34			—			27.71
	Income (loss) before income taxes	101,668		(1,636		)	(1,227		)	(439		)	(3,014		)	95,352
	Segment capital expenditures	30,407		4,805			29,247			14,539			11			79,009
Long-lived Assets by Geographical Area	'
		As at March 31, 2014
	(Thousands of U.S. Dollars)	Colombia		Argentina			Peru			Brazil			All Other			Total
	Property, plant and equipment	$	859,500	$	92,103		$	199,216		$	141,773		$	3,114		$	1,295,706
	Goodwill	102,581		—			—			—			—			102,581
	All other assets	262,269		35,646			27,850			24,336			211,607			561,708
	Total Assets	$	1,224,350	$	127,749		$	227,066		$	166,109		$	214,721		$	1,959,995
		As at December 31, 2013
	(Thousands of U.S. Dollars)	Colombia		Argentina			Peru			Brazil			All Other			Total
	Property, plant and equipment	$	850,359	$	94,366		$	178,531		$	133,874		$	3,042		$	1,260,172
	Goodwill	102,581		—			—			—			—			102,581
	All other assets	233,336		39,209			24,240			24,477			220,535			541,797
	Total Assets	$	1,186,276	$	133,575		$	202,771		$	158,351		$	223,577		$	1,904,550

Property_Plant_and_Equipment_a1

Property, Plant and Equipment and Inventory (Tables)	3 Months Ended
	Mar. 31, 2014
Property, Plant and Equipment [Abstract]	'
Schedule of Property, Plant and Equipment	'
	Property, Plant and Equipment
		As at March 31, 2014							As at December 31, 2013
	(Thousands of U.S. Dollars)	Cost		Accumulated			Net book value		Cost		Accumulated			Net book value
				depletion,							depletion,
				depreciation							depreciation
				and							and
				impairment							impairment
	Oil and natural gas properties
	Proved	$	1,853,547	$	(1,057,717	)	$	795,830	$	1,799,544	$	(1,005,475	)	$	794,069
	Unproved	489,817		—			489,817		456,001		—			456,001
		2,343,364		(1,057,717		)	1,285,647		2,255,545		(1,005,475		)	1,250,070
	Furniture and fixtures and leasehold improvements	9,182		(6,989		)	2,193		8,919		(6,568		)	2,351
	Computer equipment	15,297		(8,019		)	7,278		14,786		(7,605		)	7,181
	Automobiles	1,425		(837		)	588		1,381		(811		)	570
	Total Property, Plant and Equipment	$	2,369,268	$	(1,073,562	)	$	1,295,706	$	2,280,631	$	(1,020,459	)	$	1,260,172

Share_Capital_Tables

Share Capital (Tables)	3 Months Ended
	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
RSU's and Stock options outstanding	'
	The following table provides information about RSU and stock option activity for the three months ended March 31, 2014:
		RSUs			Options
		Number of Outstanding Share Units			Number of Outstanding Options			Weighted Average Exercise Price $/Option
	Balance, December 31, 2013	922,045			15,668,458			5.41
	Granted	835,490			2,237,630			7.09
	Exercised	(292,608	)		(111,333	)		(5.64	)
	Forfeited	(17,984	)		(84,156	)		(6.57	)
	Expired	—			(67,668	)		(6.81	)
	Balance, March 31, 2014	1,446,943			17,642,931			5.61
Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan	'
	The amounts recognized for stock-based compensation were as follows:
	(Thousands of U.S. Dollars)		Three Months Ended March 31,
			2014				2013
	Compensation costs for stock options		$	2,016			$	2,231
	Compensation costs for RSUs		1,244				—
			3,260				2,231
	Less: stock-based compensation costs capitalized		(783		)		(182		)
	Stock-based compensation costs expensed		$	2,477			$	2,049
Weighted average shares outstanding	'
			Three Months Ended March 31,
			2014			2013
	Weighted average number of common and exchangeable shares outstanding		283,235,202			282,138,525
	Shares issuable pursuant to stock options		14,553,754			5,482,456
	Shares assumed to be purchased from proceeds of stock options		(9,152,052	)		(2,594,798	)
	Weighted average number of diluted common and exchangeable shares outstanding		288,636,904			285,026,183

Asset_Retirement_Obligation_Ta

Asset Retirement Obligation (Tables)	3 Months Ended
	Mar. 31, 2014
Asset Retirement Obligation [Abstract]	'
Changes in Asset Retirement Obligations	'
	Changes in the carrying amounts of the asset retirement obligation associated with the Company’s oil and natural gas properties were as follows:
		Three Months Ended			Year Ended
	(Thousands of U.S. Dollars)	March 31, 2014			December 31, 2013
	Balance, beginning of year	$	21,973		$	18,292
	Settlements	—			(2,068		)
	Liability incurred	786			2,623
	Foreign exchange	(5		)	(25		)
	Accretion	418			1,279
	Revisions in estimated liability	—			1,872
	Balance, end of period	$	23,172		$	21,973
	Asset retirement obligation - current	$	518		$	518
	Asset retirement obligation - long-term	22,654			21,455
	Balance, end of period	$	23,172		$	21,973

Taxes_Tables

Taxes (Tables)	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Income tax expense reported reconciliation to computed statutory rate	'
	The income tax expense reported differs from the amount computed by applying the U.S. statutory rate to income before income taxes for the following reasons:
		Three Months Ended March 31,
	(Thousands of U.S. Dollars)	2014			2013
	Income (loss) before income taxes
	United States	$	(5,078	)	$	(2,091	)
	Foreign	80,386			97,443
		75,308			95,352
		35		%	35		%
	Income tax expense expected	26,358			33,373
	Foreign currency translation adjustments	4,160			(1,878		)
	Impact of foreign taxes	(1,093		)	(224		)
	Stock-based compensation	760			686
	(Decrease) increase in valuation allowance	(2,439		)	1,844
	Branch and other foreign loss pick-up	254			(827		)
	Non-deductible third party royalty in Colombia	2,223			3,547
	Other permanent differences	(44		)	918
	Total income tax expense	$	30,179		$	37,439
	Current income tax expense
	United States	$	357		$	306
	Foreign	32,082			44,583
		32,439			44,889
	Deferred income tax recovery
	United States	—			—
	Foreign	(2,260		)	(7,450		)
		(2,260		)	(7,450		)
	Total income tax expense	$	30,179		$	37,439
Deferred tax assets and liabilities	'
		As at
	(Thousands of U.S. Dollars)	March 31, 2014			31-Dec-13
	Deferred Tax Assets
	Tax benefit of operating loss carryforwards	$	45,630		$	47,154
	Tax basis in excess of book basis	57,340			59,168
	Foreign tax credits and other accruals	35,619			34,894
	Tax benefit of capital loss carryforwards	4,838			4,769
	Deferred tax assets before valuation allowance	143,427			145,985
	Valuation allowance	(141,282		)	(142,322		)
		$	2,145		$	3,663
	Deferred tax assets - current	$	770		$	2,256
	Deferred tax assets - long-term	1,375			1,407
		2,145			3,663
	Deferred tax liabilities - current	(1,265		)	(1,193		)
	Deferred tax liabilities - long-term	(169,798		)	(177,082		)
		(171,063		)	(178,275		)
	Net Deferred Tax Liabilities	$	(168,918	)	$	(174,612	)
Schedule of Unrecognized Tax Benefits Roll Forward	'
	Changes in the Company's unrecognized tax benefit are as follows:
		Three Months Ended March 31,
		2014			2013
	(Thousands of U.S. Dollars)
	Unrecognized tax benefit at beginning of period	$	22,100		$	21,800
	Decreases for positions relating to prior year	(1,100		)	—
	Additions to tax position related to the current year	1,500			—
	Unrecognized tax benefit at end of period	$	22,500		$	21,800

Financial_Instruments_Fair_Val1

Financial Instruments, Fair Value Measurements and Credit Risk (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair Value of Foreign Currency Derivatives, Contingent Consideration and Contingent Liability	'
	The fair value of the foreign currency derivatives, contingent consideration and the contingent liability at March 31, 2014, and December 31, 2013, were as follows:
		As at
	(Thousands of U.S. Dollars)	31-Mar-14			31-Dec-13
	Foreign currency derivative asset	$	2,409		$	—
	Contingent consideration	$	1,061		$	1,061
	Contingent liability (Note 8)	$	4,400		$	4,400
Gains Associated with Foreign Currency Derivatives	'
	The following table presents gains or losses on financial instruments recognized in the accompanying condensed consolidated statements of operations:
	(Thousands of U.S. Dollars)	Three Months Ended March 31,
		2014			2013
	Foreign currency derivative gains	$	2,409		$	—
Open Foreign Currency Derivative Positions	'
	At March 31, 2014, the Company had the following open foreign currency derivative position:
	Forward contracts
	Currency	Contract Type	Notional (Billions of Colombian Pesos)	Weighted Average Fixed Rate Received (Colombian Pesos - U.S. Dollars)		Expiration
	Colombian pesos	Buy	109.3	2,037		Apr-14
	Colombian pesos	Buy	40.5	2,045		Jun-14
			149.8

Segment_and_Geographic_Reporti2

Segment and Geographic Reporting - Reportable Segments (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Oil and natural gas sales	$168,525	$204,780
Interest income	1,154	591
Depletion, depreciation, accretion and impairment	53,157	58,412
Depletion, depreciation, accretion and impairment - per unit of production	27.07	27.71
Income (loss) before income taxes	75,308	95,352
Segment capital expenditures	88,637	79,009
Colombia [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Oil and natural gas sales	144,935	180,003
Interest income	137	161
Depletion, depreciation, accretion and impairment	41,250	45,956
Depletion, depreciation, accretion and impairment - per unit of production	25.44	26.32
Income (loss) before income taxes	86,011	101,668
Segment capital expenditures	50,543	30,407
Argentina [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Oil and natural gas sales	17,420	18,540
Interest income	404	243
Depletion, depreciation, accretion and impairment	8,893	7,950
Depletion, depreciation, accretion and impairment - per unit of production	32.23	26.68
Income (loss) before income taxes	-4,152	-1,636
Segment capital expenditures	6,536	4,805
Peru [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Oil and natural gas sales	0	0
Interest income	0	14
Depletion, depreciation, accretion and impairment	208	62
Depletion, depreciation, accretion and impairment - per unit of production	0	0
Income (loss) before income taxes	-2,058	-1,227
Segment capital expenditures	20,893	29,247
Brazil [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Oil and natural gas sales	6,170	6,237
Interest income	425	9
Depletion, depreciation, accretion and impairment	2,579	4,171
Depletion, depreciation, accretion and impairment - per unit of production	38.89	65.34
Income (loss) before income taxes	1,950	-439
Segment capital expenditures	10,366	14,539
All Other [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Oil and natural gas sales	0	0
Interest income	188	164
Depletion, depreciation, accretion and impairment	227	273
Depletion, depreciation, accretion and impairment - per unit of production	0	0
Income (loss) before income taxes	-6,443	-3,014
Segment capital expenditures	$299	$11

Segment_and_Geographic_Reporti3

Segment and Geographic Reporting - Assets (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	$1,295,706	$1,260,172
Goodwill	102,581	102,581
All other assets	561,708	541,797
Total Assets	1,959,995	1,904,550
Colombia [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	859,500	850,359
Goodwill	102,581	102,581
All other assets	262,269	233,336
Total Assets	1,224,350	1,186,276
Argentina [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	92,103	94,366
Goodwill	0	0
All other assets	35,646	39,209
Total Assets	127,749	133,575
Peru [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	199,216	178,531
Goodwill	0	0
All other assets	27,850	24,240
Total Assets	227,066	202,771
Brazil [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	141,773	133,874
Goodwill	0	0
All other assets	24,336	24,477
Total Assets	166,109	158,351
All Other [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	3,114	3,042
Goodwill	0	0
All other assets	211,607	220,535
Total Assets	$214,721	$223,577

Segment_and_Geographic_Reporti4

Segment and Geographic Reporting - Narrative (Details) (Colombia [Member])	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
	customer	customer
Concentration Risk [Line Items]	'	'
Number of significant customers	2	3
Number of other significant customers	1	2
Ecopetrol [Member]	'	'
Concentration Risk [Line Items]	'	'
Sales to Ecopetrol, as a percentage of total revenue (in hundredths)	43.00%	54.00%
Other Customer Number One [Member]	'	'
Concentration Risk [Line Items]	'	'
Sales to Ecopetrol, as a percentage of total revenue (in hundredths)	37.00%	21.00%
Other Customer Number Two [Member]	'	'
Concentration Risk [Line Items]	'	'
Sales to Ecopetrol, as a percentage of total revenue (in hundredths)	'	11.00%

Property_Plant_and_Equipment_a2

Property, Plant and Equipment and Inventory (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'
Cost	$2,369,268	$2,280,631
Accumulated depletion, depreciation and impairment	-1,073,562	-1,020,459
Total Property, Plant and Equipment (Note 4)	1,295,706	1,260,172
Unproved oil and gas property full cost accounting	489,817	456,001
Proved [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	1,853,547	1,799,544
Accumulated depletion, depreciation and impairment	-1,057,717	-1,005,475
Total Property, Plant and Equipment (Note 4)	795,830	794,069
Unproved [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Accumulated depletion, depreciation and impairment	0	0
Total Property, Plant and Equipment (Note 4)	489,817	456,001
Unproved oil and gas property full cost accounting	489,817	456,001
Oil and natural gas properties depletable base under full cost accounting [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	2,343,364	2,255,545
Accumulated depletion, depreciation and impairment	-1,057,717	-1,005,475
Total Property, Plant and Equipment (Note 4)	1,285,647	1,250,070
Furniture and fixtures and leasehold improvements [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	9,182	8,919
Accumulated depletion, depreciation and impairment	-6,989	-6,568
Total Property, Plant and Equipment (Note 4)	2,193	2,351
Computer equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	15,297	14,786
Accumulated depletion, depreciation and impairment	-8,019	-7,605
Total Property, Plant and Equipment (Note 4)	7,278	7,181
Automobiles [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	1,425	1,381
Accumulated depletion, depreciation and impairment	-837	-811
Total Property, Plant and Equipment (Note 4)	$588	$570

Property_Plant_and_Equipment_a3

Property, Plant and Equipment and Inventory - Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Property, Plant and Equipment [Line Items]	'	'	'
Depreciation and depletion	$53,100,000	$54,600,000	'
Unproven properties relating to four blocks	1,295,706,000	'	1,260,172,000
Unproved assets by cost center	489,800,000	'	456,000,000
Crude oil inventories	12,100,000	'	11,700,000
Supplies	2,300,000	'	2,000,000
Colombia [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Unproved assets by cost center	184,000,000	'	176,100,000
Argentina [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Unproved assets by cost center	17,700,000	'	18,200,000
Peru [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Unproved assets by cost center	198,100,000	'	177,500,000
Brazil [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Unproved assets by cost center	90,000,000	'	84,200,000
Brazil [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Number of unproved reserves blocks	4	'	'
Four out of Seven Blocks Unproved Oil and Gas Properties [Member] | Brazil [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Unproven properties relating to four blocks	$71,900,000	'	'

Share_Capital_Details

Share Capital (Details) (USD $)	3 Months Ended
	Mar. 31, 2014
Number of Outstanding Options	'
Balance, December 31, 2012 (in shares)	15,668,458
Granted (in shares)	2,237,630
Exercised (in shares)	-111,333
Forfeited (in shares)	-84,156
Expired (in shares)	-67,668
Balance, June 30, 2013 (in shares)	17,642,931
Weighted Average Exercise Price $/Option	'
Weighted Average Exercise Price $/Option, beginning balance (in dollars per share)	$5.41
Weighted Average Exercise Price $/Option, Granted (in dollars per share)	$7.09
Weighted Average Exercise Price $/Options Exercised (in dollars per share)	($5.64)
Weighted Average Exercise Price $/Options, Forfeited (in dollars per share)	($6.57)
Weighted Average Exercise Price $/Options, Expired (in dollars per share)	($6.81)
Weighted Average Exercise Price $/Option, ending balance (in dollars per share)	$5.61
RSUs [Member]	'
Number of Outstanding Share Units	'
Balance, December 31, 2012 (in shares)	922,045
Granted (in shares)	835,490
Exercised (in shares)	-292,608
Forfeited (in shares)	-17,984
Expired (in shares)	0
Balance, June 30, 2013 (in shares)	1,446,943

Share_Capital_Allocation_of_Sh

Share Capital - Allocation of Share Based Compensation (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Compensation cost	$3,260	$2,231
Less: stock-based compensation costs capitalized	-783	-182
Stock-based compensation costs expensed	2,477	2,049
Stock Options [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Compensation cost	2,016	2,231
RSUs [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Compensation cost	$1,244	$0

Share_Capital_Weighted_Average

Share Capital - Weighted Average Shares (Details)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'
Weighted average number of common and exchangeable shares outstanding	283,235,202	282,138,525
Shares issuable pursuant to stock options	14,553,754	5,482,456
Shares assumed to be purchased from proceeds of stock options	-9,152,052	-2,594,798
Weighted average number of diluted common and exchangeable shares outstanding	288,636,904	285,026,183

Share_Capital_Narrative_Detail

Share Capital - Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
	vote
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]	'	'	'
Authorized share capital	595,000,002	'	'
Common stock, authorized	570,000,000	'	'
Common shares, par value (in dollars per share)	$0.00	'	$0.00
Preferred stock, authorized	25,000,000	'	'
Preferred stock, par value (in dollars per share)	$0.00	'	'
Special voting stock-authorized (in shares)	2	'	'
Special voting stock-par value (in dollars per share)	$0.00	'	'
Common shares, outstanding	272,792,843	'	272,327,810
Stock issued during period upon exercise of stock options (in shares)	111,333	'	'
Votes per common stock	1	'	'
Common voting shares per exchangeable share (in shares)	1	'	'
Cash received from exercise of stock options	$600,000	$1,600,000	'
Stock option exercises in period (in shares)	-111,333	'	'
Stock Options [Abstract]	'	'	'
Stock-based compensation expense	2,477,000	2,049,000	'
Unvested stock options recognition period	'2 years 2 months 12 days	'	'
General and Administrative Expense [Member]	'	'	'
Stock Options [Abstract]	'	'	'
Stock-based compensation expense	2,200,000	1,800,000	'
Stock Options [Member]	'	'	'
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]	'	'	'
Weighted Average Grant Date Fair Value $/Option, Granted in Period	$2.52	$3.33	'
Stock Options [Abstract]	'	'	'
Unrecognized compensation cost related to unvested stock options	16,100,000	'	8,100,000
Earnings Per Share [Abstract]	'	'	'
Options excluded from the diluted income per share calculation	3,175,152	9,392,605	'
Stock Options [Member] | Operating Expense [Member]	'	'	'
Stock Options [Abstract]	'	'	'
Stock-based compensation expense	$300,000	$200,000	'
Gran Tierra Exchangeco Inc [Member]	'	'	'
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]	'	'	'
Exchangeable shares outstanding (in shares)	5,994,613	'	'
Exchange shares issued during period	353,700	'	'
Gran Tierra Goldstrike Inc [Member]	'	'	'
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]	'	'	'
Exchangeable shares outstanding (in shares)	4,534,127	'	'

Asset_Retirement_Obligation_De

Asset Retirement Obligation (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2012	Dec. 31, 2013
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]	'	'	'
Balance, beginning of year	$21,973,000	'	'
Settlements	0	-2,068,000	'
Liability incurred	786,000	2,623,000	'
Foreign exchange	-5,000	-25,000	'
Accretion	418,000	1,279,000	'
Revisions in estimated liability	0	1,872,000	'
Balance, end of period	23,172,000	18,292,000	'
Asset retirement obligation - current	518,000	'	518,000
Asset retirement obligation - long-term	22,654,000	'	21,455,000
Balance, end of period	23,172,000	18,292,000	'
Fair value of legally restricted assets	$2,000,000	'	$1,900,000

Taxes_Income_Tax_Reconciliatio

Taxes - Income Tax Reconciliation (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Income (loss) before income taxes	'	'
United States	($5,078)	($2,091)
Foreign	80,386	97,443
INCOME BEFORE INCOME TAXES	75,308	95,352
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]	'	'
Effective income tax rate	35.00%	35.00%
Income tax expense expected	26,358	33,373
Foreign currency translation adjustments	4,160	-1,878
Impact of foreign taxes	-1,093	-224
Stock-based compensation	760	686
(Decrease) increase in valuation allowance	-2,439	1,844
Branch and other foreign loss pick-up	254	-827
Non-deductible third party royalty in Colombia	2,223	3,547
Other permanent differences	-44	918
Total income tax expense	30,179	37,439
Current income tax expense	'	'
United States	357	306
Foreign	32,082	44,583
Total Current income tax expense	32,439	44,889
Deferred income tax recovery	'	'
United States	0	0
Foreign	-2,260	-7,450
Total Deferred income tax expense (recovery)	($2,260)	($7,450)

Taxes_Permanent_Differences_Re

Taxes - Permanent Differences Reconciliation (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Income Tax Disclosure [Abstract]	'	'
Tax benefit of operating loss carryforwards	$45,630	$47,154
Tax basis in excess of book basis	57,340	59,168
Foreign tax credits and other accruals	35,619	34,894
Tax benefit of capital loss carryforwards	4,838	4,769
Deferred tax assets before valuation allowance	143,427	145,985
Valuation allowance	-141,282	-142,322
Deferred tax assets, net	2,145	3,663
Deferred tax assets - current	770	2,256
Deferred tax assets - long-term	1,375	1,407
Deferred tax liabilities - current	-1,265	-1,193
Deferred tax liabilities - long-term	-169,798	-177,082
Deferred tax liabilities, net	-171,063	-178,275
Net Deferred Tax Liabilities	($168,918)	($174,612)

Taxes_Unrecognized_Tax_Benefit

Taxes - Unrecognized Tax Benefits Rollforward (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]	'	'
Unrecognized tax benefit at beginning of period	$22,100	$21,800
Changes for positions relating to prior year	-1,100	0
Additions to tax position related to the current year	1,500	0
Unrecognized tax benefit at end of period	$22,500	$21,800

Taxes_Narrative_Details

Taxes - Narrative (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2013	Mar. 31, 2013
		installment
Income Tax Disclosure [Abstract]	'	'	'	'	'
Operating loss carryforwards	$206,800,000	'	'	$215,400,000	'
Capital losses before valuation allowance	32,800,000	'	'	32,600,000	'
Net operating loss and capital loss carryforward from foreign subsidiaries	203,500,000	'	'	213,800,000	'
Unrecognized tax benefits	22,500,000	'	21,800,000	22,100,000	21,800,000
Unrecognized tax benefits that would impact effective tax rate	$12,800,000	'	'	'	'
Equity tax rate (in hundredths)	6.00%	'	6.00%	'	'
Equity tax for foreign operations - Columbia, number of semi-annual installments	'	8	'	'	'
Equity tax for foreign operations - Columbia, assessment term (in years)	'	'4 years	'	'	'

Contingencies_Details

Contingencies (Details) (USD $)	3 Months Ended	12 Months Ended	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2014
			Pending Litigation Escopetrol [Member]	Pending Litigation Escopetrol [Member]	Pending Litigation Moqueta Discovery [Member]	Pending Litigation Royalty, Transportation and Related Costs [Member]
				bbl	bbl
Loss Contingencies [Line Items]	'	'	'	'	'	'
Loss Contingency, Loss in Period, Barrels of Oil	'	'	'	44,025	'	'
Contingent liability (Note 8)	$4,400,000	$4,400,000	$4,400,000	'	$44,900,000	$31,700,000
Threshold by which additional royalty due (barrels)	'	'	'	'	5,000,000	'
Total cumulative production of oil field (barrels)	'	'	'	'	2,700,000	'
Promissory notes provided as collateral for letters of credit	$52,500,000	$52,500,000	'	'	'	'

Financial_Instruments_Fair_Val2

Financial Instruments, Fair Value Measurements and Credit Risk - Narrative (Details) (USD $)	3 Months Ended							0 Months Ended
	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2014	Oct. 08, 2012
		Colombia [Member]	Colombia [Member]	Colombia [Member]	Colombia [Member]	Argentina [Member]	Brazil [Member]	Block-Brazil [Member]
		customer	customer	Sales Revenue, Segment [Member]	Sales Revenue, Segment [Member]	customer	customer
				Geographic Concentration Risk [Member]	Geographic Concentration Risk [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'	'	'
Participating interest percentage oil and gas property, remaining percentage	'	'	'	'	'	'	'	30.00%
Number of significant customers	'	2	3	'	'	3	1	'
Concentration risk, percentage	'	'	'	85.00%	88.00%	'	'	'
Cash and cash equivalents on deposit with local Argentinian banks	'	'	'	'	'	$15,100,000	'	'
Cash and cash equivalents on deposit with local Argentinian bank, percent	'	'	'	'	'	4.00%	'	'
Foreign exchange losses, Colombian peso to U.S. dollar	$87,000	'	'	'	'	'	'	'

Financial_Instruments_Fair_Val3

Financial Instruments, Fair Value Measurements and Credit Risk - Fair Value of the Foreign Currency Derivatives, Contingent Consideration and the Contingent Liability (Details) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'	'
Foreign currency derivative asset	$2,409	$0
Contingent consideration	1,061	1,061
Contingent liability (Note 8)	$4,400	$4,400

Financial_Instruments_Fair_Val4

Financial Instruments, Fair Value Measurements and Credit Risk - Gains Recognized in the Statement of Operations (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Fair Value Disclosures [Abstract]	'	'
Foreign currency derivative gains	$2,409	$0

Financial_Instruments_Fair_Val5

Financial Instruments, Fair Value Measurements and Credit Risk - Open Foreign Currency Derivative Position (Details) (Foreign Exchange Forward [Member])	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014
In Billions, unless otherwise specified	USD ($)	Forward Contract Expiring April 2014 [Member]	Forward Contract Expiring June 2014 [Member]
		Long [Member]	Long [Member]
		COP	COP
Derivative [Line Items]	'	'	'
Notional amount	$149.80	109.3	40.5
Weighted Average Fixed Rate Received	'	2,037	2,045