Gran Tierra Energy (GTE) 10-K 26 Feb 14 2013 FY Annual report Financial data

Document_And_Entity_Informatio

Document And Entity Information (USD $)	12 Months Ended
In Billions, except Share data, unless otherwise specified	Dec. 31, 2013	Feb. 19, 2014	Jun. 30, 2013
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 Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Public Float	'	'	$1.60
Entity Common Stock, Shares Outstanding	'	272,341,810	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Document Type	'10-K	'	'
Amendment Flag	'false	'	'
Document Period End Date	31-Dec-13	'	'

Consolidated_Statements_of_Ope

Consolidated Statements of Operations and Retained Earnings (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
REVENUE AND OTHER INCOME	'	'	'
Oil and natural gas sales	$720,450	$583,109	$596,191
Interest income	3,193	2,078	1,216
Total revenue and other income	723,643	585,187	597,407
EXPENSES	'	'	'
Operating	149,059	124,903	86,497
Depletion, depreciation, accretion and impairment	267,146	182,037	231,235
General and administrative	53,400	58,882	60,389
Other gain (Note 9)	0	-9,336	0
Other loss (Notes 11 and 12)	4,400	0	0
Equity tax (Note 9)	0	0	8,271
Financial instruments gain (Note 3)	0	0	-1,522
Gain on acquisition (Note 3)	0	0	-21,699
Foreign exchange (gain) loss	-12,198	31,338	-11
Total expenses	461,807	387,824	363,160
INCOME BEFORE INCOME TAXES	261,836	197,363	234,247
Income tax expense (Note 9)	-135,548	-97,704	-107,330
NET INCOME AND COMPREHENSIVE INCOME	126,288	99,659	126,917
RETAINED EARNINGS, BEGINNING OF YEAR	284,673	185,014	58,097
RETAINED EARNINGS, END OF YEAR	$410,961	$284,673	$185,014
NET INCOME PER SHARE — BASIC (in dollars per share)	$0.45	$0.35	$0.46
NET INCOME PER SHARE — DILUTED (in dollars per share)	$0.44	$0.35	$0.45
WEIGHTED AVERAGE SHARES OUTSTANDING - BASIC (Note 7)	282,808,497	280,741,255	273,491,564
WEIGHTED AVERAGE SHARES OUTSTANDING - DILUTED (Note 7)	286,127,897	284,172,254	281,287,002

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current Assets	'	'
Cash and cash equivalents	$428,800	$212,624
Restricted cash	1,478	1,404
Accounts receivable (Note 5)	49,703	119,844
Inventory (Note 5)	13,725	33,468
Taxes receivable	9,980	39,922
Prepaids	6,450	4,074
Deferred tax assets (Note 9)	2,256	2,517
Total Current Assets	512,392	413,853
Oil and Gas Properties (using the full cost method of accounting)	'	'
Proved	794,069	813,247
Unproved	456,001	383,414
Total Oil and Gas Properties	1,250,070	1,196,661
Other capital assets	10,102	8,765
Total Property, Plant and Equipment (Note 6)	1,260,172	1,205,426
Other Long-Term Assets	'	'
Restricted cash	2,300	1,619
Deferred tax assets (Note 9)	1,407	1,401
Taxes receivable	18,535	1,374
Other long-term assets	7,163	6,621
Goodwill (Note 2)	102,581	102,581
Total Other Long-Term Assets	131,986	113,596
Total Assets	1,904,550	1,732,875
Current Liabilities	'	'
Accounts payable (Note 10)	72,400	102,263
Accrued liabilities (Note 10)	89,567	66,418
Taxes payable	102,887	22,339
Deferred tax liabilities (Note 9)	1,193	337
Asset retirement obligation (Note 8)	518	28
Total Current Liabilities	266,565	191,385
Long-Term Liabilities	'	'
Deferred tax liabilities (Note 9)	177,082	225,195
Equity tax payable	0	3,562
Asset retirement obligation (Note 8)	21,455	18,264
Other long-term liabilities	9,540	3,038
Total Long-Term Liabilities	208,077	250,059
Commitments and Contingencies (Note 11)	'	'
Shareholders’ Equity	'	'
Common Stock (Note 7) (272,327,810 and 268,482,445 shares of Common Stock and 10,882,440 and 13,421,488 exchangeable shares, par value $0.001 per share, issued and outstanding as at December 31, 2013 and December 31, 2012, respectively)	10,187	7,986
Additional paid in capital	1,008,760	998,772
Retained earnings	410,961	284,673
Total Shareholders’ Equity	1,429,908	1,291,431
Total Liabilities and Shareholders’ Equity	$1,904,550	$1,732,875

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]	'	'
Common shares, par value (in dollars per share)	$0.00	$0.00
Common shares, issued	272,327,810	268,482,445
Common shares, outstanding	272,327,810	268,482,445
Exchangeable shares, issued	10,882,440	13,421,488
Exchangeable shares, outstanding	10,882,440	13,421,488

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Activities	'	'	'
Net income	$126,288	$99,659	$126,917
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'
Depletion, depreciation, accretion and impairment	267,146	182,037	231,235
Deferred tax (recovery) expense (Note 9)	-29,499	26,274	-28,685
Stock-based compensation (Note 7)	8,918	12,006	12,767
Unrealized gain on financial instruments (Note 3)	0	0	-1,354
Unrealized foreign exchange (gain) loss	-18,911	17,054	-2,232
Cash settlement of asset retirement obligation (Note 8)	-2,068	-404	-345
Other gain (Note 9)	0	-9,336	0
Other loss (Notes 11 and 12)	4,400	0	0
Equity tax	-3,345	-3,534	2,442
Gain on acquisition (Note 3)	0	0	-21,699
Net change in assets and liabilities from operating activities	'	'	'
Accounts receivable and other long-term assets	67,034	-56,669	-15,627
Inventory	13,947	-18,195	-548
Prepaids	-2,375	-477	-1,321
Accounts payable and accrued and other liabilities	-5,170	-8,387	16,780
Taxes receivable and payable	94,496	-83,709	35,422
Net cash provided by operating activities	520,861	156,319	353,752
Investing Activities	'	'	'
(Increase) decrease in restricted cash	-755	11,859	-10,197
Additions to property, plant and equipment	-367,322	-276,084	-333,194
Proceeds from oil and gas properties (Note 6)	59,621	0	4,450
Cash paid for acquisition (Note 3)	0	-35,495	0
Cash acquired on acquisition (Note 3)	0	0	7,747
Proceeds on sale of asset-backed commercial paper (Note 3)	0	0	22,679
Net cash used in investing activities	-308,456	-299,720	-308,515
Financing Activities	'	'	'
Settlement of bank debt (Note 3)	0	0	-54,103
Proceeds from issuance of shares of Common Stock	3,771	4,340	5,123
Net cash provided by (used in) financing activities	3,771	4,340	-48,980
Net increase (decrease) in cash and cash equivalents	216,176	-139,061	-3,743
Cash and cash equivalents, beginning of year	212,624	351,685	355,428
Cash and cash equivalents, end of year	428,800	212,624	351,685
Cash	408,568	207,392	172,645
Term deposits	20,232	5,232	179,040
Cash and cash equivalents, end of year	428,800	212,624	351,685
Supplemental cash flow disclosures:	'	'	'
Cash paid for interest (Note 3)	0	0	1,604
Cash paid for income taxes	51,183	143,498	67,053
Non-cash investing activities:	'	'	'
Non-cash net assets and liabilities related to property, plant and equipment, end of year	$75,580	$75,393	$43,333

Consolidated_Statements_of_Sha

Consolidated Statements of Shareholders' Equity (USD $)	Total	Share Capital [Member]	Additional Paid-in Capital [Member]	Warrants [Member]	Retained Earnings [Member]
In Thousands
Balance, beginning of year at Dec. 31, 2010	'	$4,797	$821,781	$2,191	$58,097
Issue of shares of Common Stock	'	2,713	142,109	'	'
Exercise of warrants (Note 7)	'	'	411	-411	'
Expiry of warrants (Note 7)	'	'	0	0	'
Exercise of stock options (Note 7)	'	'	1,990	'	'
Stock-based compensation (Note 7)	'	'	13,723	'	'
Net income	126,917	'	'	'	126,917
Balance, end of year at Dec. 31, 2011	1,174,318	7,510	980,014	1,780	185,014
Issue of shares of Common Stock	'	476	2,902	'	'
Exercise of warrants (Note 7)	'	'	1,590	-1,590	'
Expiry of warrants (Note 7)	'	'	190	-190	'
Exercise of stock options (Note 7)	'	'	960	'	'
Stock-based compensation (Note 7)	'	'	13,116	'	'
Net income	99,659	'	'	'	99,659
Balance, end of year at Dec. 31, 2012	1,291,431	7,986	998,772	0	284,673
Issue of shares of Common Stock	'	2,201	0	'	'
Exercise of warrants (Note 7)	'	'	0	0	'
Expiry of warrants (Note 7)	'	'	0	0	'
Exercise of stock options (Note 7)	'	'	1,570	'	'
Stock-based compensation (Note 7)	'	'	8,418	'	'
Net income	126,288	'	'	'	126,288
Balance, end of year at Dec. 31, 2013	$1,429,908	$10,187	$1,008,760	$0	$410,961

Description_of_Business

Description of Business	12 Months Ended
	Dec. 31, 2013
Description of Business [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	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Significant Accounting Policies	'
	Significant Accounting Policies
	The consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”). The Company believes that the information and disclosures presented are adequate to ensure the information presented is not misleading.
	Significant accounting policies are:
	Basis of consolidation
	These consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated.
	Use of estimates
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates made by management include: oil and natural gas reserves and related present value of future cash flows; depreciation, depletion, amortization and impairment (“DD&A”); impairment assessments of goodwill; timing of transfers from oil and gas properties not subject to depletion to the depletable base; asset retirement obligations; determining the value of the consideration transferred and the net identifiable assets acquired and liabilities assumed in connection with business combinations and determining goodwill; income taxes; legal and other contingencies; and stock-based compensation. Although management believes these estimates are reasonable, changes in facts and circumstances or discovery of new information may result in revised estimates, and actual results may differ from these estimates.
	Cash and cash equivalents
	The Company considers all highly liquid investments with an original maturity of three months or less to be cash equivalents.
	Restricted cash
	Restricted cash comprises cash and cash equivalents pledged to secure letters of credit and to settle asset retirement obligations. Letters of credit currently secured by cash relate to work commitment guarantees contained in exploration contracts. Cash and claims to cash that are restricted as to withdrawal or use for other than current operations or are designated for expenditure in the acquisition or construction of long-term assets are excluded from the current asset classification.
	Allowance for doubtful accounts
	The Company estimates losses on receivables based on known uncollectible accounts, if any, and historical experience of losses incurred and accrues a reserve on a receivable when, based on the judgment of management, it is probable that a receivable will not be collected and the amount of the reserve may be reasonably estimated. The allowance for doubtful receivables was nil at December 31, 2013, and 2012.
	Inventory
	Inventory consists of oil in tanks and third party pipelines, and supplies and is valued at the lower of cost or market value. The cost of inventory is determined using the weighted average method. Oil inventories include expenditures incurred to produce, upgrade and transport the product to the storage facilities and include operating, depletion and depreciation expenses and cash royalties.
	Income taxes
	Income taxes are recognized using the liability method, whereby deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the consolidated financial statement carrying amounts of existing assets and liabilities and their respective tax base, and operating loss and tax credit carry forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences and carryforwards are expected to be recovered or settled. Valuation allowances are provided if, after considering available evidence, it is not more likely than not that some or all of the deferred tax assets will be realized.
	The tax benefit from an uncertain tax position is recognized when it is more likely than not, based on the technical merits of the position, that the position will be sustained on examination by the taxing authorities. Additionally, the amount of the tax benefit recognized is the largest amount of benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. In evaluating whether a tax position has met the more-likely-than-not recognition threshold, the Company presumes that the position will be examined by the appropriate taxing authority that has full knowledge of all relevant information. The Company recognizes potential penalties and interest related to unrecognized tax benefits as a component of income tax expense.
	Oil and gas properties
	The Company uses the full cost method of accounting for its investment in oil and natural gas properties as defined by the Securities and Exchange Commission (“SEC”). Under this method, the Company capitalizes all acquisition, exploration and development costs incurred for the purpose of finding oil and natural gas reserves, including salaries, benefits and other internal costs directly attributable to these activities. Costs associated with production and general corporate activities; however, are expensed as incurred. Interest costs related to unproved properties and properties under development are also capitalized to oil and natural gas properties. Separate cost centers are maintained for each country in which the Company incurs costs.
	The Company computes depletion of oil and natural gas properties on a quarterly basis using the unit-of-production method based upon production and estimates of proved reserve quantities. Future development costs related to properties with proved reserves are also included in the amortization base for computation of depletion. The costs of unproved properties are excluded from the amortization base until the properties are evaluated. The cost of exploratory dry wells is transferred to proved properties, and thus is subject to amortization, immediately upon determination that a well is dry in those countries where proved reserves exist.
	The Company performs a ceiling test calculation each quarter in accordance with SEC Regulation S-X Rule 4-10. In performing its quarterly ceiling test, the Company limits, on a country-by-country basis, the capitalized costs of proved oil and natural gas properties, net of accumulated depletion and deferred income taxes, to the estimated future net cash flows from proved oil and natural gas reserves discounted at 10%, net of related tax effects, plus the lower of cost or fair value of unproved properties included in the costs being amortized. If such capitalized costs exceed the ceiling, the Company will record a write-down to the extent of such excess as a non-cash charge to net income. Any such write-down will reduce earnings in the period of occurrence and results in a lower DD&A rate in future periods. A write-down may not be reversed in future periods even though higher oil and natural gas prices may subsequently increase the ceiling.
	The Company calculates future net cash flows by applying the unweighted average of prices in effect on the first day of the month for the preceding 12-month period, adjusted for location and quality differentials. Such prices are utilized except where different prices are fixed and determinable from applicable contracts for the remaining term of those contracts.
	Unproved properties are not depleted pending the determination of the existence of proved reserves. Costs are transferred into the depletable base on an ongoing basis as the properties are evaluated and proved reserves are established or impairment is determined. Unproved properties are evaluated quarterly to ascertain whether impairment has occurred. This evaluation considers, among other factors, seismic data, requirements to relinquish acreage, drilling results and activity, remaining time in the commitment period, remaining capital plans, and political, economic, and market conditions. During any period in which factors indicate an impairment, the cumulative costs incurred to date for such property are transferred to the full cost pool and are then subject to depletion. For countries where a reserve base has not yet been established, the impairment is charged to earnings.
	In exploration areas, related geological and geophysical (“G&G”) costs are capitalized in unproved property and evaluated as part of the total capitalized costs associated with a property. G&G costs related to development projects are recorded in proved properties and therefore subject to depletion as incurred.
	Gains and losses on the sale or other disposition of oil and natural gas properties are not recognized, unless the gain or loss would significantly alter the relationship between capitalized costs and proved reserves of oil and natural gas attributable to a country.
	Asset retirement obligation
	The Company records an estimated liability for future costs associated with the abandonment of its oil and gas properties including the costs of reclamation of drilling sites. The Company records the fair value of a liability for a legal obligation to retire an asset in the period in which the liability is incurred with an offsetting increase to the related oil and gas properties. 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. 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. The accretion of the asset retirement obligation and amortization of the asset retirement cost are included in DD&A. If estimated future costs of an asset retirement obligation change, an adjustment is recorded to both the asset retirement obligation and oil and gas properties. Revisions to the estimated asset retirement obligation can result from changes in retirement cost estimates, revisions to estimated inflation rates and changes in the estimated timing of abandonment.
	Other capital assets
	Other capital assets, including additions and replacements, are recorded at cost upon acquisition and include furniture, fixtures and leasehold improvement, computer equipment and automobiles. Depreciation is provided using the declining-balance method at a 30% annual rate for furniture and fixtures, computer equipment and automobiles. Leasehold improvements are depreciated on a straight-line basis over the shorter of the estimated useful life and the term of the related lease. The cost of repairs and maintenance is charged to expense as incurred.
	Goodwill
	Goodwill represents the excess of the aggregate of the consideration transferred over the net identifiable assets acquired and liabilities assumed. The Company assesses qualitative factors annually, or more frequently if necessary, to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount and whether it is necessary to perform the two-step goodwill impairment test. The impairment test requires allocating goodwill and certain other assets and liabilities to assigned reporting units. The fair value of each reporting unit is estimated and compared with the net book value of the reporting unit. If the estimated fair value of the reporting unit is less than the net book value, including goodwill, then the goodwill is written down to the implied fair value of the goodwill through a charge to expense. Because quoted market prices are not available for the Company’s reporting units, the fair values of the reporting units are estimated based upon estimated future cash flows of the reporting unit.
	The Company recorded $87.6 million of goodwill in relation to the acquisition of Solana Resources Limited (“Solana”) in 2008 and $15.0 million of goodwill in relation to the Argosy Energy International L.P. acquisition in 2006. The goodwill relates entirely to the Colombia reportable segment. The Company performed a qualitative assessment of goodwill at December 31, 2013, and based on this assessment, no impairment of goodwill was identified.
	Revenue recognition
	Revenue from the production of oil and natural gas is recognized when the customer has taken title and has assumed the risks and rewards of ownership, prices are fixed or determinable, the sale is evidenced by a contract and collection of the revenue is reasonably assured.
	On February 1, 2012, the sales point for the Company’s Colombian oil sales to a significant customer in the Putumayo Basin changed. Gran Tierra’s customer, Ecopetrol S.A. (“Ecopetrol”), now takes title at the Port of Tumaco on the Pacific coast of Colombia rather than at the entry into the Ecopetrol-operated Trans-Andean oil pipeline (“the OTA pipeline”) at the Orito Station in the Putumayo Basin. In Colombia, the Company has other sales contracts where the sales point is the purchaser's facilities or when oil is loaded into a truck at Gran Tierra's loading facility or an export tanker.
	In Argentina, Gran Tierra transports oil from the field to the customer’s refinery or the oil terminal by pipeline or truck, where title is transferred. For the Company’s gas sales in Argentina, Gran Tierra’s customers take title when the gas is transferred to their pipeline. In Brazil, Gran Tierra transports product from the field to the customer’s station by truck, where title is transferred.
	Revenue represents the Company’s share and is recorded net of royalty payments to governments and other mineral interest owners.
	Stock-based compensation
	The Company grants time-vested restricted stock units ("RSUs") to officers, employees and consultants. RSUs entitle the holder to receive, at the option of the Company, either the underlying number of shares of the Company's Common Stock upon vesting of such shares or a cash payment equal to the value of the underlying shares. The Company expects its practice will be to settle RSUs in cash and, therefore, RSUs are accounted for as liability instruments. Compensation expense for RSUs granted is based on the estimated fair value, which is determined using the closing share price, at each reporting date, and the expense, net of estimated forfeitures, is recognized over the requisite service period using the accelerated method, with a corresponding change to liabilities. An adjustment is made to compensation expense for any difference between the estimated forfeitures and the actual forfeitures related to vested awards.
	Additionally, the Company grants options to purchase shares of Common Stock to certain directors, officers, employees and consultants. The Company follows the fair-value based method of accounting for stock options granted. Compensation expense for options granted is based on the estimated fair value, using the Black-Scholes option pricing model, at the time of grant and the expense, net of estimated forfeitures, is recognized over the requisite service period using the accelerated method. An adjustment is made to compensation expense for any difference between the estimated forfeitures and the actual forfeitures related to vested awards. The Company uses historical data to estimate option exercises, expected term and employee departure behavior used in the Black-Scholes option pricing model. Expected volatilities used in the fair value estimate are based on historical volatility of the Company’s shares. The risk-free rate for periods within the expected term of the stock options is based on the U.S. Treasury yield curve in effect at the time of grant.
	Stock-based compensation expense relating to RSUs and stock options is capitalized as part of oil and natural gas properties or expensed as part of operating expenses or general and administrative (“G&A”) expenses, as appropriate.
	Warrants
	The Company issued warrants (“Replacement Warrants”) in connection with its acquisition of Petrolifera Petroleum Limited (“Petrolifera”) in March 2011 (Note 3). The Replacement Warrants expired unexercised during August 2011. These warrants were derivative financial instruments and were recognized at fair value in the consolidated balance sheet as a current liability and as part of the consideration paid for the acquisition. The Company determined the fair value of warrants issued using the Black-Scholes option pricing model.
	Foreign currency translation
	The functional currency of the Company, including its subsidiaries, is the United States dollar. Monetary items are translated into the reporting currency at the exchange rate in effect at the balance sheet date and non-monetary items are translated at historical exchange rates. Revenue and expense items are translated in a manner that produces substantially the same reporting currency amounts that would have resulted had the underlying transactions been translated on the dates they occurred.
	Depreciation or amortization of assets is translated at the historical exchange rates similar to the assets to which they relate.
	Gains and losses resulting from foreign currency transactions, which are transactions denominated in a currency other than the entity’s functional currency, are recognized in net income.
	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.
	Recently Issued 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 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The implementation of this update is not expected to materially impact the Company’s consolidated financial position, results of operations or 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 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The implementation of this update is not expected to materially impact the Company’s consolidated financial position, results of operations or cash flows or disclosure.

Business_Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2013
Business Combinations [Abstract]	'
Business Combinations	'
	Business Combination
	Brazil
	On October 8, 2012, the Company received regulatory approval and acquired the remaining 30% working interest in four blocks in Brazil pursuant to the terms of a purchase and sale agreement dated January 20, 2012. With the exception of one block which has three producing wells, the remaining blocks are unproved properties.
	The Company paid initial cash purchase consideration of $28.0 million and an interim period purchase price adjustment of $7.5 million, representing the 30% share of all benefits and costs with respect to the period between the effective date and the completion of the transaction. Contingent consideration up to an additional $3.0 million may be payable dependent on production volumes from the acquired blocks.
	The acquisition was accounted for as a business combination using the acquisition method, with Gran Tierra being the acquirer, whereby the assets acquired and liabilities assumed were recognized at their fair values as at October 8, 2012, the acquisition date, and the results of the blocks were included with those of Gran Tierra from that date. Fair value estimates were made based on significant unobservable (Level 3) inputs and based on the best information available at the time.
	Contingent consideration was recorded on the balance sheet at the acquisition date fair value based on the consideration expected to be transferred, 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 acquisition date fair value of the contingent consideration was $1.1 million and was recorded in other long-term liabilities. The fair value of the contingent consideration is being remeasured at the estimated fair value at each reporting period and any change in fair value will be recognized as income or expense in operating income. There was no significant change in the fair value of the contingent consideration between October 8, 2012, December 31, 2012, and December 31, 2013. Any changes in fair value will impact earnings in such reporting period until the contingencies are resolved.
	The following table shows the allocation of the consideration transferred based on the fair values of the assets and liabilities acquired:
	(Thousands of U.S. Dollars)
	Consideration Transferred:
	Cash	$	35,495
	Fair value of contingent consideration payable	1,061
		$	36,556
	Allocation of Consideration Transferred:
	Oil and gas properties
	Proved	$	24,107
	Unproved	12,859
	Asset retirement obligation	(410		)
		$	36,556
	Pro forma results (unaudited)
	Pro forma results related to this acquisition have not been disclosed because oil and natural gas sales and net income related to the 30% working interest for the years ended December 31, 2012, and 2011 were not material in relation to the Company's consolidated financial statements. Production from these blocks was not significant during these periods.
	Petrolifera Petroleum Limited
	On March 18, 2011 (the “Acquisition Date”), Gran Tierra completed its acquisition of all the issued and outstanding common shares and warrants of Petrolifera, a Canadian corporation, pursuant to the terms and conditions of an arrangement agreement dated January 17, 2011 (the “Arrangement”). Petrolifera is a Calgary based oil, natural gas and natural gas liquids exploration, development and production company active in Argentina, Colombia and Peru. The transaction contemplated by the Arrangement was effected through a court approved plan of arrangement in Canada. The Arrangement was approved at a special meeting of Petrolifera shareholders on March 17, 2011, and by the Court of Queen's Bench of Alberta on March 18, 2011.
	Under the Arrangement, Petrolifera shareholders received, for each Petrolifera share held, 0.1241 of a share of Gran Tierra Common Stock, and Petrolifera warrant holders received, for each Petrolifera warrant held, 0.1241 of a warrant (a "Replacement Warrant") to purchase a share of Gran Tierra Common Stock at an exercise price of $9.67 Canadian (“CDN”) dollars per share. The Replacement Warrants expired unexercised on August 28, 2011.
	Gran Tierra acquired all the issued and outstanding Petrolifera shares and warrants through the issuance of 18,075,247 shares of Gran Tierra Common Stock, par value $0.001, and 4,125,036 Replacement Warrants. Upon completion of the transaction on the Acquisition Date, Petrolifera became an indirect wholly-owned subsidiary of Gran Tierra. On a diluted basis, upon the closing of the Arrangement, Petrolifera and Gran Tierra security holders owned approximately 6.6% and 93.4% of the Company, respectively, immediately following the transaction. The total consideration for the transaction was approximately $143.0 million.
	The fair value of Gran Tierra’s Common Stock was determined as the closing price of shares of the Common Stock of Gran Tierra as at the Acquisition Date.
	The fair value of the Replacement Warrants was estimated on the Acquisition Date using the Black-Scholes option pricing model with the following assumptions:
	Exercise price (CDN dollars per warrant)	$	9.67
	Risk-free interest rate	1.3		%
	Expected life	0.45 years
	Volatility	44		%
	Expected annual dividend per share	Nil
	Estimated fair value per warrant (CDN dollars)	$	0.32
	The Replacement Warrants met the definition of a derivative and, due to the fact that the exercise price of the Replacement Warrants was denominated in Canadian dollars, which is different from Gran Tierra’s functional currency, the Replacement Warrants were not considered indexed to Gran Tierra’s shares of Common Stock and the Replacement Warrants could not be classified within equity. Therefore, the Replacement Warrants were classified as a current liability on Gran Tierra’s consolidated balance sheet. Furthermore, these derivative instruments did not qualify as fair value hedges or cash flow hedges, and accordingly, changes in their fair value were recognized as income or expense in the consolidated statement of operations with a corresponding adjustment to the fair value of derivative instruments recognized on the balance sheet. The financial instruments gain for the year ended December 31, 2011, included a $1.3 million gain arising from the fair value of the expired Replacement Warrants.
	The acquisition was accounted for using the acquisition method, with Gran Tierra being the acquirer, whereby Petrolifera’s assets acquired and liabilities assumed are recognized at their fair values as at the Acquisition Date and the results of Petrolifera have been consolidated with those of Gran Tierra from that date.
	The following table shows the allocation of the consideration transferred based on the fair values of the assets and liabilities acquired:
	(Thousands of U.S. Dollars)
	Consideration Transferred:
	Shares of Common Stock issued net of share issue costs	$	141,690
	Replacement warrants	1,354
		$	143,044
	Allocation of Consideration Transferred:
	Oil and gas properties
	Proved	$	58,457
	Unproved	161,278
	Other long-term assets	4,417
	Net working capital (including cash acquired of $7.7 million and accounts receivable of $6.4 million)	(17,223		)
	Asset retirement obligation	(4,901		)
	Bank debt	(22,853		)
	Other long-term liabilities	(14,432		)
	Gain on acquisition	(21,699		)
		$	143,044
	As shown above, the fair value of identifiable assets acquired and liabilities assumed exceeded the fair value of the consideration transferred. Consequently, Gran Tierra reassessed the recognition and measurement of identifiable assets acquired and liabilities assumed and concluded that all acquired assets and assumed liabilities were recognized and that the valuation procedures and resulting measures were appropriate. As a result, Gran Tierra recognized a gain of $21.7 million, which was reported as “Gain on acquisition” in the consolidated statement of operations. The gain reflected the impact on Petrolifera’s pre-acquisition market value of a lack of liquidity and capital resources required to maintain current production and reserves and further develop and explore their inventory of prospects.
	As part of the assets acquired and included in the net working capital in the allocation of the consideration transferred, the Company assigned $22.5 million in fair value to investments in notes that Petrolifera received in exchange for asset-backed commercial paper (“ABCP”) with a face value of $31.3 million. On March 28, 2011, these notes were sold to an unrelated party for proceeds of $22.7 million after the associated line of credit was settled. When combined with the gain arising on expiry of the Replacement Warrants, the financial instruments gain for the year ended December 31, 2011, was $1.5 million.
	The associated ABCP line of credit that Gran Tierra assumed was with a Canadian chartered bank, to a maximum of CDN$23.2 million with an initial expiry in April 2012. Gran Tierra settled this line of credit immediately after the completion of the acquisition of Petrolifera for the face value of CDN$22.5 million in borrowings plus accrued interest.
	Also upon the acquisition of Petrolifera, Gran Tierra assumed a second line of credit agreement (“Second ABCP line of credit”) with the same Canadian chartered bank to a maximum of CDN$5.0 million, which was fully drawn as at the Acquisition Date. This Second ABCP line of credit, which expired on April 8, 2011, was secured by ineligible master asset vehicles Classes 1 & 2 (“MAV IA 1 & 2”) notes with a face value of $6.6 million. Gran Tierra retained the option to settle the Second ABCP line of credit of CDN$5.0 million through delivery to the lender of the MAV IA 1 & 2 notes. Subsequent to the acquisition, Gran Tierra elected to record this second line of credit at fair value and planned at that time to settle the debt through delivery of the MAV IA 1 & 2 notes. Accordingly, a value of $nil was recorded for the debt upon its acquisition. Gran Tierra settled such borrowings by delivery of the MAV IA 1 & 2 notes on April 8, 2011.
	Gran Tierra also assumed a reserve-backed credit facility upon the Petrolifera acquisition with an outstanding balance of $31.3 million. The amount outstanding under this credit facility was included as part of net working capital in the allocation of consideration transferred. The credit facility bore interest at LIBOR plus 8.25% and was partially secured by the pledge of the shares of Petrolifera’s subsidiaries. The outstanding balance was repaid when the Argentina restriction preventing its repayment expired on August 5, 2011, resulting in a total debt repayment of $54.1 million, when combined with the repayment of the CDN$22.5 million ABCP line of credit. Interest expense on the credit facility for the 140-day period from the Acquisition Date to August 5, 2011, was $1.6 million. This amount is recorded in the consolidated statements of operations as part of G&A expenses in the Argentina segment.
	Pro forma results (unaudited)
	Pro forma results for the year ended December 31, 2011, are shown below, as if the acquisition had occurred on January 1, 2010. Pro forma results are not indicative of actual results or future performance.
		Year Ended December 31,
	(Unaudited, thousands of U.S. Dollars, except per share amounts)	2011
	Revenue and other income	$	606,602
	Net income	$	94,094
	Net income per share - basic	$	0.34
Net income per share - diluted	$	0.33
The supplemental pro forma earnings of Gran Tierra for the year ended December 31, 2011, were adjusted to exclude $4.4 million of acquisition costs recorded in G&A expenses and the $21.7 million gain on acquisition because they were not expected to have a continuing impact on Gran Tierra’s results of operations. The consolidated statement of operations for the year ended December 31, 2011, included revenue of $32.5 million from Petrolifera for the period subsequent to the Acquisition Date. Petrolifera incurred a loss after tax of $8.0 million in the period from the Acquisition Date to December 31, 2011.

Segment_and_Geographic_Reporti

Segment and Geographic Reporting	12 Months Ended
	Dec. 31, 2013
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 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 accounting policies of the reportable segments are the same as those described in Note 2. The Company evaluates reportable segment performance based on income or loss before income taxes. The segmented results include the operations of Petrolifera subsequent to March 18, 2011, the Acquisition Date (Note 3).
	The following tables present information on the Company’s reportable segments and other activities:
		Year Ended December 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	$	624,410	$	73,495		$	—		$	22,545		$	—		$	720,450
	Interest income	623		1,015			27			909			619			3,193
	DD&A expenses	184,697		64,295			362			16,761			1,031			267,146
	DD&A - per unit of production	27.23		58.18			—			70.12			—			32.87
	Income (loss) before income taxes	336,179		(47,378		)	(7,067		)	(2,650		)	(17,248		)	261,836
	Segment capital expenditures (1)	188,547		19,503			82,954			23,039			775			314,818
		Year Ended December 31, 2012
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Argentina			Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	493,615	$	79,642		$	—		$	9,852		$	—		$	583,109
	Interest income	667		355			49			607			400			2,078
	DD&A expenses	122,055		31,466			1,234			26,300			982			182,037
	DD&A - per unit of production	25.37		24.74			—			259.88			—			29.44
	Income (loss) before income taxes	244,474		1,060			(5,493		)	(24,543		)	(18,135		)	197,363
	Segment capital expenditures (1)	153,331		40,653			62,869			55,239			1,084			313,176
		Year Ended December 31, 2011
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Argentina			Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	543,999	$	48,016		$	—		$	4,176		$	—		$	596,191
	Interest income	492		66			140			84			434			1,216
	DD&A expenses	141,133		45,506			42,035			1,819			742			231,235
	DD&A - per unit of production	26.17		49.61			—			42.25			—			36.39
	Income (loss) before income taxes	313,516		(32,635		)	(46,249		)	(3,878		)	3,493			234,247
	Segment capital expenditures (1)	202,551		36,289			36,224			50,836			1,747			327,647
	(1) In 2013, segment capital expenditures are net of proceeds of: $54.0 million relating to termination of a farm-in agreement in Brazil; $4.1 million relating to the Company's assumption of the remaining 50% working interest in the Santa Victoria Block in Argentina; and $1.5 million relating to the Company's sale of its 15% working interest in the Mecaya Block in Colombia (Note 6). In 2012, the Company paid $35.5 million and recorded $1.1 million of contingent consideration in connection with the acquisition of the remaining 30% working interest in four blocks in Brazil (Note 3). In 2011, amounts are net of proceeds from the farm-out of a 50% working interest in the Santa Victoria Block and the sale of a blow-out preventer, both in Argentina (Note 6). In 2011, the Company also completed its acquisition of all the issued and outstanding common shares and warrants of Petrolifera (Note 3).
	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.
	The Company has two significant customers in Colombia, Ecopetrol and one other customer. Sales to Ecopetrol accounted for 41%, 74% and 87% of the Company's consolidated oil and gas sales for the years ended December 31, 2013, 2012 and 2011, respectively. Sales to the other customer in Colombia accounted for 38% of the Company's consolidated oil and gas sales for the year ended December 31, 2013.
		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
	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
		As at December 31, 2012
	(Thousands of U.S. Dollars)	Colombia		Argentina			Peru			Brazil			All Other			Total
	Property, plant and equipment	$	840,027	$	138,768		$	95,940		$	127,394		$	3,297		$	1,205,426
	Goodwill	102,581		—			—			—			—			102,581
	Other assets	222,220		47,038			10,880			8,498			136,232			424,868
	Total Assets	$	1,164,828	$	185,806		$	106,820		$	135,892		$	139,529		$	1,732,875

Accounts_Receivable_and_Invent

Accounts Receivable and Inventory	12 Months Ended
	Dec. 31, 2013
Receivables [Abstract]	'
Accounts Receivable and Inventory	'
	Accounts Receivable and Inventory
	Accounts Receivable
		As at December 31,
	(Thousands of U.S. Dollars)	2013		2012
	Trade	$	46,113	$	116,434
	Other	3,590		3,410
		$	49,703	$	119,844
	Inventory
	At December 31, 2013, oil and supplies inventories were $11.7 million and $2.0 million, respectively (December 31, 2012 - $31.2 million and $2.3 million, respectively).

Property_Plant_and_Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2013
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment	'
	Property, Plant and Equipment
	Property, Plant and Equipment
		As at December 31, 2013								As at December 31, 2012
	(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	$	1,799,544		$	(1,005,475	)	$	794,069	$	1,562,477	$	(749,230	)	$	813,247
	Unproved	456,001			—			456,001		383,414		—			383,414
		2,255,545			(1,005,475		)	1,250,070		1,945,891		(749,230		)	1,196,661
	Furniture and fixtures and leasehold improvements	8,919			(6,568		)	2,351		7,575		(5,093		)	2,482
	Computer equipment	14,786			(7,605		)	7,181		10,971		(5,248		)	5,723
	Automobiles	1,381			(811		)	570		1,376		(816		)	560
	Total Property, Plant and Equipment	$	2,280,631		$	(1,020,459	)	$	1,260,172	$	1,965,813	$	(760,387	)	$	1,205,426
	Depletion and depreciation expense on property, plant and equipment for the year ended December 31, 2013, was $227.3 million (year ended December 31, 2012 - $168.0 million; year ended December 31, 2011 - $162.6 million). A portion of depletion and depreciation expense was recorded as inventory in each year and adjusted for inventory changes.
	In the second quarter of 2013, the Company assumed its partner's 50% working interest in the Santa Victoria Block in Argentina and received cash consideration of $4.1 million from its partner, comprising the balance owing for carry consideration and compensation for the second exploration phase work commitment. The Company also received proceeds of $1.5 million relating to a sale of its 15% working interest in the Mecaya Block in Colombia.
	In the third quarter of 2013, the Company received a net payment of $54.0 million (before income taxes) from a third party in connection with termination of a farm-in agreement in the Recôncavo Basin relating to Block REC-T-129, Block REC-T-142, Block REC-T-155 and Block REC-T-224 in Brazil.
	The Company successfully bid on three blocks in the 2013 Brazil Bid Round 11 administered by Brazil's Agência Nacional de Petróleo, Gás Natural e Biocombustíveis ("ANP") and, in the third quarter of 2013, paid a signature bonus of $14.4 million upon finalization of the concession agreements.
	On June 5, 2012, the Company received regulatory approval of a farm-in agreement on a block in Colombia. This approval triggered a payment of $21.1 million related to drilling costs for a previously drilled oil exploration well, which was recorded as a capital expenditure in the second quarter of 2012.
	Effective June 1, 2012, the Company entered into an agreement to acquire the remaining 40% working interest in a block in Peru. The block is an unproved property. Purchase consideration was $5.4 million and was recorded as a capital expenditure in the second quarter of 2012.
	On August 26, 2010, the Company entered into an agreement to acquire a 70% working interest in four blocks in Brazil. The agreement was effective September 1, 2010, subject to regulatory approvals, and the transaction was completed on June 15, 2011. Purchase consideration was $40.1 million and was recorded as capital expenditures in 2011 and 2010. On January 20, 2012, the Company entered into an agreement to acquire the remaining 30% working interest in these four blocks and, on October 8, 2012, received regulatory approval and acquired the remaining 30% working interest. The 30% working interest acquisition was accounted for as a business combination using the acquisition method (Note 3).
	In September 2011, the Company announced two farm-out agreements with Statoil do Brasil Ltda. ("Statoil") in a joint venture with PetróleoBrasileiro S.A. pursuant to which, the Company would receive an assignment of a non-operated 10% working interest in Block BM-CAL-7 and a non-operated 15% working interest in Block BM-CAL-10. Both blocks are located in the Camamu Basin, offshore Bahia, Brazil. On February 17, 2012, in accordance with the terms of the farm-out agreement for Block BM-CAL-10 in Brazil, the Company gave notice to its joint venture partner that it would not enter into and assume its share of the work obligations of the second exploration period of the block. As a result, the farm-out agreement terminated and the Company did not receive any interest in this block. Pursuant to the farm-out agreement, the Company was obligated to make payment for a certain percentage of the costs relating to Block BM-CAL-10, which relate primarily to a well that was drilled during the term of the farm-out agreement. The notice of withdrawal was a trigger for payment of amounts that would otherwise have been due if the farm-out agreement had closed and the Company had acquired a working interest. In the first quarter of 2012, the Company received regulatory approval from the ANP for the Block BM-CAL-7 farm-out agreement. Purchase consideration of $0.7 million was paid and the assignment became effective on April 3, 2012. The Company relinquished its interest in Block 186 of Block BM-CAL-7 effective in the fourth quarter of 2013 and paid a penalty of $1.3 million for not meeting the first exploration phase work obligation to drill a well on this block.
	In March 2011, the Company recorded proceeds of $3.3 million from the farm-out of a 50% interest in the Santa Victoria Block in Argentina. The Company also recorded $1.2 million from the sale of a blow-out preventer in Argentina in September 2011.
	In the year ended December 31, 2013, the Company recorded a ceiling test impairment loss of $30.8 million in the Company's Argentina cost center as a result of deferred investment and inconclusive waterflood results and a ceiling test impairment loss of $2.0 million in the Company's Brazil cost center as a result of lower realized prices and increased operating costs.
	In the first quarter of 2012, the Company recorded a ceiling test impairment loss in the Company’s Brazil cost center of $20.2 million. This impairment loss resulted from the recognition of $23.8 million of capital expenditures in relation to the Block BM-CAL-10 farm-out agreement in the first quarter of 2012.
	In the year ended December 31, 2011, the Company recorded a ceiling test impairment loss in the Company’s Peru cost center of $42.0 million. This impairment charge related to drilling costs from a dry well and seismic costs on blocks which were relinquished.
	In the year ended December 31, 2011, the Company recorded a ceiling test impairment loss in the Company’s Argentina cost center of $25.7 million. This impairment charge related to an increase in estimated future operating and capital costs to produce the Company's remaining Argentina proved reserves and a decrease in reserve volumes.
	In Brazil, the exploration phase of the concession agreements on Blocks REC-T-129, REC-T-142 and REC-T-155 was 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 ANP for extensions or suspensions of the exploration phases of these blocks. At December 31, 2013, unproved properties included $51.4 million relating to exploration expenditures on these four blocks. Management assessed these blocks for impairment at December 31, 2013 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.
	The amounts of G&A and stock-based compensation capitalized in each of the Company's cost centers during the years ended December 31, 2013, 2012 and 2011, respectively, were as follows:
		Year Ended December 31, 2013
	(Thousands of U.S. Dollars)	Colombia			Argentina			Peru		Brazil		Total
	Capitalized G&A, including stock-based compensation	$	21,415		$	3,423		$	7,896	$	7,220	$	39,954
	Capitalized stock-based compensation	921			128			669		718		2,436
		Year Ended December 31, 2012
	(Thousands of U.S. Dollars)	Colombia			Argentina			Peru		Brazil		Total
	Capitalized G&A, including stock-based compensation	$	15,054		$	4,605		$	4,761	$	3,844	$	28,264
	Capitalized stock-based compensation	481			354			—		275		1,110
		Year Ended December 31, 2011
	(Thousands of U.S. Dollars)	Colombia			Argentina			Peru		Brazil		Total
	Capitalized G&A, including stock-based compensation	$	7,996		$	3,189		$	1,183	$	1,985	$	14,353
	Capitalized stock-based compensation	456			266			—		234		956
	Unproved oil and natural gas properties consist of exploration lands held in Colombia, Argentina, Peru and Brazil. As at December 31, 2013, the Company had $176.1 million (December 31, 2012 - $175.9 million) of unproved assets in Colombia, $18.2 million (December 31, 2012 - $42.3 million) of unproved assets in Argentina, $177.5 million (December 31, 2012 - $95.1 million) of unproved assets in Peru, and $84.2 million (December 31, 2012 - $70.1 million) of unproved assets in Brazil for a total of $456.0 million (December 31, 2012 - $383.4 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 dictates whether or not future areas will be developed. The Company expects that approximately 75% of costs not subject to depletion at December 31, 2013, will be transferred to the depletable base within the next five years and the remainder in the next five to 10 years.
	The following is a summary of Gran Tierra’s oil and natural gas properties not subject to depletion as at December 31, 2013:
		Costs Incurred in
	(Thousands of U.S. Dollars)	2013			2012			2011		Prior to 2011		Total
	Acquisition costs - Colombia	$	—		$	—		$	3,900	$	127,842	$	131,742
	Acquisition costs - Argentina	(4,088		)	—			14,889		—		10,801
	Acquisition costs - Peru	—			5,400			23,423		2,000		30,823
	Acquisition costs - Brazil	—			12,802			22,668		—		35,470
	Exploration costs - Colombia	4,965			16,092			7,225		16,064		44,346
	Exploration costs - Argentina	204			(588		)	2,595		5,226		7,437
	Exploration costs - Peru	82,311			58,286			6,019		—		146,616
	Exploration costs - Brazil	14,106			17,128			17,532		—		48,766
	Total oil and natural gas properties not subject to depletion	$	97,498		$	109,120		$	98,251	$	151,132	$	456,001

Share_Capital

Share Capital	12 Months Ended
	Dec. 31, 2013
Stockholders' Equity Note [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 December 31, 2013, outstanding share capital consists of 272,327,810 shares of Common Stock of the Company, 6,348,313 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 Exchangeco exchangeable shares were issued upon the acquisition of Solana. The Goldstrike exchangeable shares were issued upon the business combination between Gran Tierra Energy Inc., an Alberta corporation, and Goldstrike, Inc., which is now the Company.
	The redemption date of the Exchangeco exchangeable shares was previously established as November 14, 2013 (or at an earlier date under certain specified circumstances). However, pursuant to resolutions of the Board of Directors of Gran Tierra Exchangeco Inc., effective October 25, 2013, the redemption date for the Exchangeco exchangeable shares was extended to such later date as may be established by the Board of Directors of Gran Tierra Exchangeco Inc. at its discretion. The redemption date of the Goldstrike exchangeable shares was previously established as November 10, 2013. However, pursuant to resolutions of the Board of Directors of Gran Tierra Goldstrike Inc., effective October 31, 2013, the redemption date for the Goldstrike exchangeable shares was extended to such later date as may be established by the Board of Directors of Gran Tierra Goldstrike Inc. at its discretion. During the year ended December 31, 2013, 1,306,317 shares of Common Stock were issued upon the exercise of stock options, 1,689,683 shares of Common Stock were issued upon the exchange of the Goldstrike exchangeable shares and 849,365 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
	As at December 31, 2013, the Company followed the 2007 Equity Incentive Plan, formed through the approval by shareholders of the amendment and restatement of the 2005 Equity Incentive Plan, under which the Company’s Board of Directors is authorized to issue options or other rights to acquire shares of the Company’s Common Stock. On June 27, 2012, the shareholders of Gran Tierra approved an amendment to the Company’s 2007 Equity Incentive Plan, which increased the Common Stock available for issuance thereunder from 23,306,100 shares to 39,806,100 shares.
	The Company grants time-vested RSUs to officers, employees and consultants. RSUs entitle the holder to receive, at the option of the Company, either the underlying number of shares of the Company's Common Stock upon vesting of such shares or a cash payment equal to the value of the underlying shares. The Company expects its practice will be to settle RSUs in cash.
	Additionally, the Company grants options to purchase shares of Common Stock to certain directors, officers, employees and consultants. Each option permits the holder to purchase one share of Common Stock at the stated exercise price. At the time of grant, the exercise price equals the market price. Options vest over three years. The Company does not expect to repurchase any shares in the open market to settle any such exercises.
	In May 2013, the Company issued RSUs and stock options, which will vest as to 1/3 of the awards on each of March 1, 2014, March 1, 2015 and March 1, 2016. The term of options granted starting May 2013 is five years or three months after the grantee’s end of service to the Company, whichever occurs first. Options granted prior to May 2013 continue to have a term of ten years or three months after the grantee’s end of service to the Company, whichever occurs first. Once an RSU is vested, it is immediately settled and considered to be at the end of its term.
	The fair value of each stock option award is estimated on the date of grant using the Black-Scholes option pricing model based on assumptions noted in the following table:
		Year Ended December 31,
		2013		2012		2011
	Dividend yield (per share)	Nil		Nil		Nil
	Volatility	42% to 54%		59% to 75%		75% to 81%
	Weighted average volatility	53	%	75	%	80	%
	Risk-free interest rate	0.3% to 0.7%		0.3% to 0.4%		0.4% to 1.4%
	Expected term	4-5 years		4-6 years		4-6 years
	The following table provides information about stock option and RSU activity for the year ended December 31, 2013:
		RSUs		Options
		Number of Outstanding Share Units		Number of Outstanding Options			Weighted Average Exercise Price $/Option
	Balance, December 31, 2012	—		15,399,662			5.11
	Granted	966,320		2,121,375			6.29
	Exercised	—		(1,306,317	)		(2.89	)
	Forfeited	(44,275	)	(396,003	)		(7.01	)
	Expired	—		(150,259	)		(6.25	)
	Balance, December 31, 2013	922,045		15,668,458			5.41
	Exercisable, at December 31, 2013			10,372,602			4.87
	Vested, or expected to vest, at December 31, 2013, through the life of the options			15,142,311			5.37
	For the year ended December 31, 2013, 1,306,317 shares of Common Stock were issued upon the exercise of 1,306,317 stock options (2012 – 482,841; 2011 – 1,695,049). Cash proceeds from the exercise of stock options in the year ended December 31, 2013 were $3.8 million.
	At December 31, 2013, the weighted average remaining contractual term of outstanding stock options was 6.1 years and of exercisable stock options was 5.8 years.
	The weighted average grant date fair value for options granted in the year ended December 31, 2013, was $2.62 (2012 - $3.33; 2011 - $4.84). The weighted average grant date fair value for options vested in the year ended December 31, 2013, was $3.94 (2012 - $3.90; 2011 - $2.26). The total fair value of stock options vested during year ended December 31, 2013, was $12.4 million (2012 - $10.2 million; 2011 - $6.6 million).
	The amounts recognized for stock-based compensation were as follows:
	(Thousands of U.S. Dollars)		Year Ended December 31,
			2013				2012				2011
	Compensation costs for stock options		$	8,418			$	13,116			$	13,723
	Compensation costs for RSUs		2,936				—				—
			11,354				13,116				13,723
	Less: stock-based compensation costs capitalized		(2,436		)		(1,110		)		(956		)
	Total stock-based compensation expense		$	8,918			$	12,006			$	12,767
	Of the total compensation expense for the year ended December 31, 2013, $7.9 million (2012 - $10.9 million; 2011 - $11.4 million) was recorded in G&A expenses and $1.0 million (2012 – $1.1 million; 2011 - $1.3 million) was recorded in operating expenses.
	At December 31, 2013, there was $8.1 million (December 31, 2012 - $8.2 million) of unrecognized compensation cost related to unvested stock options and RSUs which is expected to be recognized over a weighted average period of 2.9 years.
	The aggregate intrinsic value of options outstanding at December 31, 2013, was $32.9 million (2012 - $17.8 million; 2011 -$14.7 million) based on the Company’s closing share price of $7.31 at December 31, 2013 (December 31, 2012 - $5.51; December 31, 2011 - $4.80). The aggregate intrinsic value of options exercisable at December 31, 2013, was $27.4 million (December 31, 2012 - $17.6 million; December 31, 2011 - $14.2 million). The aggregate intrinsic value of options exercised in the year ended December 31, 2013, was $3.3 million (2012 - $1.4 million; 2011 - $6.2 million). The aggregate intrinsic value of options vested, or expected to vest, at December 31, 2013, through the life of the options was $32.4 million and the weighted-average remaining contractual term of these options was 6.1 years.
	Warrants
	At December 31, 2013, and 2012, the Company did not have any warrants outstanding. At December 31, 2011, the Company had 6,298,230 warrants outstanding to purchase 3,149,115 shares of Common Stock for $1.05 per share, expiring between June 20, 2012, and June 30, 2012. During the year ended December 31, 2012, 2,766,834 shares of Common Stock were issued upon the exercise of 5,550,668 warrants (2011 - 735,817 shares of Common Stock were issued upon the exercise of 1,471,634 warrants), 26,190 shares of Common Stock were issued with 7,143 shares withheld in lieu of a cashless exchange upon the exercise of 66,666 warrants, and 680,896 warrants expired unexercised.
	Weighted Average Shares Outstanding
			Year Ended December 31,
			2013			2012			2011
	Weighted average number of common and exchangeable shares outstanding		282,808,497			280,741,255			273,491,564
	Shares issuable pursuant to warrants		—			175,061			2,708,183
	Shares issuable pursuant to stock options		12,041,260			5,879,929			5,143,498
	Shares assumed to be purchased from proceeds of stock options		(8,721,860	)		(2,623,991	)		(56,243	)
	Weighted average number of diluted common and exchangeable shares outstanding		286,127,897			284,172,254			281,287,002
	For the year ended December 31, 2013, 4,217,082 options (2012 - 9,784,874 options; 2011 - 3,726,999) were excluded from the diluted income per share calculation as the options were anti-dilutive.

Asset_Retirement_Obligation

Asset Retirement Obligation	12 Months Ended
	Dec. 31, 2013
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:
		Year Ended December 31,
	(Thousands of U.S. Dollars)	2013			2012
	Balance, beginning of year	$	18,292		$	12,669
	Settlements	(2,068		)	(404		)
	Liability incurred	2,623			5,190
	Liability assumed in a business combination (Note 3)	—			410
	Foreign exchange	(25		)	45
	Accretion	1,279			998
	Revisions in estimated liability	1,872			(616		)
	Balance, end of year	$	21,973		$	18,292
	Asset retirement obligation - current	$	518		$	28
	Asset retirement obligation - long-term	21,455			18,264
	Balance, end of year	$	21,973		$	18,292
	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 December 31, 2013, the fair value of assets that are legally restricted for purposes of settling asset retirement obligations was $1.9 million (December 31, 2012 - $1.3 million). These assets are included in restricted cash on the Company's balance sheet.

Taxes

Taxes	12 Months Ended
	Dec. 31, 2013
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:
		Year Ended December 31,
	(Thousands of U.S. Dollars)	2013			2012			2011
	Income (loss) before income taxes
	United States	$	(13,566	)	$	(13,918	)	$	4,984
	Foreign	275,402			211,281			229,263
		261,836			197,363			234,247
		35		%	35		%	35		%
	Income tax expense expected	91,643			69,077			81,986
	Foreign currency translation adjustments	(2,978		)	5,473			(417		)
	Impact of foreign taxes	(1,287		)	(1,833		)	3,890
	Stock-based compensation	2,859			3,982			4,013
	Increase in valuation allowance	39,028			6,709			36,815
	Branch and other foreign loss pick-up	(2,362		)	(3,809		)	(14,363		)
	Non-deductible third party royalty in Colombia	11,073			11,938			8,525
	Non-taxable gain on acquisition	—			—			(7,595		)
	Other permanent differences (1)	(2,428		)	6,167			(5,524		)
	Total income tax expense	$	135,548		$	97,704		$	107,330
	Current income tax expense
	United States	$	1,250		$	1,233		$	1,029
	Foreign	163,797			70,197			134,986
		165,047			71,430			136,015
	Deferred income tax expense (recovery)
	United States	—			—			—
	Foreign	(29,499		)	26,274			(28,685		)
		(29,499		)	26,274			(28,685		)
	Total income tax expense	$	135,548		$	97,704		$	107,330
	(1) Other permanent differences in the rate reconciliation are tax effected at the 35% statutory rate. For the year ended December 31, 2013, these differences include $9.1 million (2012 - $11.4 million) of tax basis and loss adjustments, $3.8 million (2012 - $8.7 million) of which are offset by a change in the valuation allowance and $2.9 million (2012 - $2.7 million) of which are subject to local tax at a rate of 1.75%.
	The Colombian income tax rate was 33% for the years ended December 31, 2011 and 2012. On December 26, 2012, the Colombian Congress enacted tax reform which effectively increased the income tax rate to 34% from 33%, effective January  1, 2013 until December 31, 2015. As part of this tax reform Colombia reduced the corporate income tax rate from 33% to 25% and introduced a new 9% tax (CREE tax) which was introduced in addition to the regular corporate income tax. A portion of the CREE tax is considered a minimum tax based on net equity and has not been included as part of the overall income tax expense.
	The Canadian statutory income tax rate changed from 26% for the year ended December 31, 2011 to 25% for the year ended December 31, 2012 as a result of the enacted reduction of Canadian corporate tax rates.
		As at December 31,
	(Thousands of U.S. Dollars)	2013			2012
	Deferred Tax Assets
	Tax benefit of operating loss carryforwards	$	47,154		$	51,920
	Tax basis in excess of book basis	59,168			22,519
	Foreign tax credits and other accruals	34,894			30,926
	Tax benefit of capital loss carryforwards	4,769			4,779
	Deferred tax assets before valuation allowance	145,985			110,144
	Valuation allowance	(142,322		)	(106,226		)
		$	3,663		$	3,918
	Deferred tax assets - current	$	2,256		$	2,517
	Deferred tax assets - long-term	1,407			1,401
		3,663			3,918
	Deferred tax liabilities - current	(1,193		)	(337		)
	Deferred tax liabilities - long-term	(177,082		)	(225,195		)
		(178,275		)	(225,532		)
	Net Deferred Tax Liabilities	$	(174,612	)	$	(221,614	)
	Undistributed earnings of foreign subsidiaries as of December 31, 2013, were considered to be permanently reinvested. A determination of the amount of unrecognized deferred tax liability on these undistributed earnings is not practicable.
	As at December 31, 2013, the Company had operating loss carryforwards of $215.4 million (December 31, 2012 - $213.1 million) and capital loss carryforwards of $32.6 million (December 31, 2012 – $35.9 million) before valuation allowance. Of these operating loss carryforwards and capital loss carryforwards, $213.8 million (December 31, 2012 - $215.2 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.
	The valuation allowance increased by $36.1 million during the year ended December 31, 2013. The change in the valuation allowance was primarily due to a ceiling test impairment loss of $30.8 million in Argentina (Note 6) and losses in Brazil and the U.S. The largest offset to the increase in the valuation allowance related to an Argentina entity where taxable income was generated, but sheltered by minimal notional tax credits. The Company continues to incur losses in the U.S., Peru, Brazil, Canada and certain Argentina entities.The losses are fully offset by a valuation allowance as their recognition does not meet the “more likely than not” threshold.
	As at December 31, 2013, the total amount of Gran Tierra’s unrecognized tax benefit was $22.1 million (December 31, 2012 - $21.8 million; December 31, 2011 - $20.5 million), approximately $12.6 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. As at December 31, 2013, the amount of interest and penalties on the unrecognized tax benefit included in current income tax liabilities in the consolidated balance sheet was approximately $5.4 million (December 31, 2012 - $3.6 million). Interest and penalties on the unrecognized tax benefit included in income tax expense for the year ended December 31, 2013 was $1.8 million (2012 - $2.0 million; 2011 - $0.6 million). The Company had no other material interest or penalties included in the consolidated statement of operations for the three years ended December 31, 2013, respectively.
	Changes in the Company's unrecognized tax benefit are as follows:
		Year Ended December 31,
		2013			2012			2011
	(Thousands of U.S. Dollars)
	Unrecognized tax benefit, beginning of year	$	21,800		$	20,500		$	4,175
	Increases for positions relating to prior year	3,200			1,300			585
	Additions to tax position related to the current year	—			—			15,740
	Decreases due to lapse of statute of limitations	(1,500		)	—			—
	Settlements	(1,400		)	—			—
	Unrecognized tax benefit, end of year	$	22,100		$	21,800		$	20,500
	The Company and its subsidiaries file income tax returns in the U.S. and certain other foreign jurisdictions. The Company is potentially subject to income tax examinations for the tax years 2005 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.
The other gain for the year ended December 31, 2012, of $9.3 million represented a value added tax recovery which occurred upon the completion of a reorganization of subsidiary companies and their Colombian branches in the Colombian reporting segment during the fourth quarter of 2012.
Equity tax for the year ended December 31, 2011, of $8.3 million represented a Colombian tax of 6% on a legislated measure and was 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 at December 31, 2013, and December 31, 2012, was also partially related to an equity tax liability assumed upon the acquisition of Petrolifera.

Accounts_Payable_and_Accrued_L

Accounts Payable and Accrued Liabilities	12 Months Ended
	Dec. 31, 2013
Payables and Accruals [Abstract]	'
Accounts Payable and Accrued Liabilities	'
	Accounts Payable and Accrued Liabilities
		As at December 31,
	(Thousands of U.S. Dollars)	2013		2012
	Trade	$	97,947	$	103,720
	Royalties	14,969		17,607
	VAT and withholding tax	24,882		28,169
	Employee compensation	16,525		13,178
	Other	7,644		6,007
		$	161,967	$	168,681

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	Purchase Obligations, Firm Agreements and Leases
	The following is a schedule by year of purchase obligations, future minimum payments for firm agreements and leases that have initial or remaining lease terms in excess of one year as of December 31, 2013:
		Year ending December 31
		Total		2014		2015		2016		2017		2018		Thereafter
	(Thousands of U.S. Dollars)
	Oil transportation services	$	52,339	$	23,261	$	10,635	$	3,812	$	3,812	$	3,812	$	7,007
	Drilling and G&G	56,143		55,806		337		—		—		—		—
	Completions	48,500		26,544		14,289		7,667		—		—		—
	Facility construction	19,446		18,748		698		—		—		—		—
	Operating leases	3,949		2,690		989		163		26		16		65
	Software and telecommunication	1,992		1,824		137		31		—		—		—
	Consulting	1,225		937		288		—		—		—		—
		$	183,594	$	129,810	$	27,373	$	11,673	$	3,838	$	3,828	$	7,072
	Gran Tierra leases certain office space, compressors, vehicles, equipment and housing. Total rent expense for the year ended December 31, 2013, was $3.1 million (year ended December 31, 2012 – $2.7 million; year ended December 31, 2011 - $3.0 million).
	Indemnities
	Corporate indemnities have been provided by the Company to directors and officers for various items including, but not limited to, all costs to settle suits or actions due to their association with the Company and its subsidiaries and/or affiliates, subject to certain restrictions. The Company has purchased directors’ and officers’ liability insurance to mitigate the cost of any potential future suits or actions. The maximum amount of any potential future payment cannot be reasonably estimated. The Company may provide indemnifications in the normal course of business that are often standard contractual terms to counterparties in certain transactions such as purchase and sale agreements. The terms of these indemnifications will vary based upon the contract, the nature of which prevents the Company from making a reasonable estimate of the maximum potential amounts that may be required to be paid.
	Letters of credit
	At December 31, 2013, the Company had provided promissory notes totaling $52.5 million (December 31, 2012 - $34.2 million) as security for letters of credit relating to work commitment guarantees contained in exploration contracts and other capital or operating requirements.
	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 year ended December 31, 2013, based on market oil prices in Colombia, Gran Tierra accrued $4.4 million in the consolidated financial statements in relation to this dispute.
	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 has 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. As at December 31, 2013, total cumulative production from the Moqueta Exploitation Area was 2.3 MMbbl. The estimated compensation which would be payable on cumulative production to that date if the ANH is successful in the arbitration is $38.4 million. At this time no amount has been accrued in the 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 our understanding of the ANH's position, the estimated compensation which would be payable if the ANH’s interpretation is correct could be up to $28.9 million as at December 31, 2013. 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.
	Gran Tierra has several other lawsuits and claims pending. 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.

Financial_Instruments_Fair_Val

Financial Instruments, Fair Value Measurements and Credit Risk	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Financial Instruments, Fair Value Measurements and Credit Risk	'
	Financial Instruments, Fair Value Measurements and Credit Risk
	At December 31, 2013, the Company’s financial instruments recognized in the balance sheet consist of cash and cash equivalents, restricted cash, accounts receivable, accounts payable, accrued liabilities 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.
	Contingent consideration, which relates to the acquisition of the remaining 30% working interest in certain properties in Brazil (Note 3), 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 contingent liability which relates to a dispute with Ecopetrol (Note 11) was based on the fair value of the amount awarded using market oil prices in Colombia. The fair value of the 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 income or expense in operating income. The fair value of the contingent consideration and this contingent liability at December 31, 2013 and December 31, 2012 were as follows:
		As at December 31,
	(Thousands of U.S. Dollars)	2013		2012
	Contingent consideration (Note 3)	$	1,061	$	1,061
	Contingent liability (Note 11)	$	4,400	$	—
	The fair values of other financial instruments approximate their carrying amounts due to the short-term maturity of these instruments. At December 31, 2013 and December 31, 2012, the Company held no derivative 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 December 31, 2013, the fair value of the contingent liability which relates to a dispute with Ecopetrol (Note 11) was determined using Level 1 inputs and the fair value of the contingent consideration payable in connection with the Brazil acquisition (Note 3) was determined using Level 3 inputs. The disclosure in the paragraph above regarding the fair value of cash and restricted cash is based on Level 1 inputs.
	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 and accounts receivables. The carrying value of cash and accounts receivable reflects management’s assessment of credit risk.
	At December 31, 2013, 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. Any foreign currency transactions are conducted on a spot basis with major financial institutions in the Company’s operating areas.
	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 year ended December 31, 2013, the Company had two customers which were significant to the Colombian segment, three customers which were significant to the Argentine segment and one customer which was significant to the Brazil segment.
	For the year ended December 31, 2013, 86% (year ended December 31, 2012 - 84%, year ended December 31, 2011 - 91%) of the Company's revenue and other income was generated in Colombia.
	Additionally, foreign exchange gains and losses mainly 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 foreign 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 $90,000 for each one peso decrease in the exchange rate of the Colombian peso to one U.S. dollar.
	In February 2014, the Company purchased non-deliverable forward contracts totaling 149.8 billion Colombian Pesos 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. As a result, the Company will effectively settle its 2013 Colombian income tax liability at exchange rates ranging from 2,034 to 2,053 Colombian Pesos to the U.S. dollar.
	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 payments. During the year ended December 31, 2013, the Company repatriated $11.1 million from one of its Argentina subsidiaries through loan repayments, authorized by the Argentina Central Bank. These were repayments of loan principal and as such had no withholding tax applied. At December 31, 2013, $19.5 million, or 5%, of our cash and cash equivalents was deposited with banks in Argentina.

Credit_Facilities

Credit Facilities	12 Months Ended
	Dec. 31, 2013
Line of Credit Facility [Abstract]	'
Credit Facilities	'
	Credit Facilities
	At December 31, 2013, a subsidiary of Gran Tierra had a credit facility with a syndicate of banks, led by Wells Fargo Bank National Association as administrative agent. This reserve-based facility has a current borrowing base of $150 million and a maximum borrowing base of up to $300 million and is supported by the present value of the petroleum reserves of two of the Company’s subsidiaries with operating branches in Colombia and the Company's subsidiary in Brazil. Amounts drawn down under the facility bear interest at the U.S. dollar LIBOR rate plus a margin ranging between 2.25% and 3.25% per annum depending on the rate of borrowing base utilization. In addition, a stand-by fee of 0.875% per annum is charged on the unutilized balance of the committed borrowing base and is included in G&A expenses. The credit facility was entered into on August 30, 2013 and became effective on October 31, 2013 for a three-year term. As at December 31, 2013, the Company had not drawn down any amounts under this facility. Under the terms of the facility, the Company is required to maintain and was in compliance with certain financial and operating covenants. Under the terms of the credit facility, the Company cannot pay any dividends to its shareholders if it is in default under the facility and, if the Company is not in default, then it is required to obtain bank approval for any dividend payments exceeding $2 million in any fiscal year.

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2013
Related Party Transactions [Abstract]	'
Related Party Transactions	'
	Related Party Transactions
	On August 7, 2012, Gran Tierra entered into a contract related to the Brazil drilling program with a company for which one of Gran Tierra’s directors is a shareholder and was a director. During the year ended December 31, 2013, $11.9 million was incurred and capitalized under this contract and at December 31, 2013, $2.0 million was included in accounts payable relating to this contract. Similarly, on August 3, 2010, Gran Tierra entered into a contract related to the Peru drilling program with the same company and $1.7 million was incurred and capitalized under this contract during the year ended December 31, 2012, and at December 31, 2012, $1.1 million was included in accounts payable relating to this contract.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Basis of consolidation	'
	Basis of consolidation
	These consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated.
Use of estimates	'
	Use of estimates
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates made by management include: oil and natural gas reserves and related present value of future cash flows; depreciation, depletion, amortization and impairment (“DD&A”); impairment assessments of goodwill; timing of transfers from oil and gas properties not subject to depletion to the depletable base; asset retirement obligations; determining the value of the consideration transferred and the net identifiable assets acquired and liabilities assumed in connection with business combinations and determining goodwill; income taxes; legal and other contingencies; and stock-based compensation. Although management believes these estimates are reasonable, changes in facts and circumstances or discovery of new information may result in revised estimates, and actual results may differ from these estimates.
Cash and cash equivalents	'
	Cash and cash equivalents
	The Company considers all highly liquid investments with an original maturity of three months or less to be cash equivalents.
Restricted cash	'
	Restricted cash
	Restricted cash comprises cash and cash equivalents pledged to secure letters of credit and to settle asset retirement obligations. Letters of credit currently secured by cash relate to work commitment guarantees contained in exploration contracts. Cash and claims to cash that are restricted as to withdrawal or use for other than current operations or are designated for expenditure in the acquisition or construction of long-term assets are excluded from the current asset classification.
Allowance for doubtful accounts	'
	Allowance for doubtful accounts
	The Company estimates losses on receivables based on known uncollectible accounts, if any, and historical experience of losses incurred and accrues a reserve on a receivable when, based on the judgment of management, it is probable that a receivable will not be collected and the amount of the reserve may be reasonably estimated.
Inventory	'
	Inventory
	Inventory consists of oil in tanks and third party pipelines, and supplies and is valued at the lower of cost or market value. The cost of inventory is determined using the weighted average method. Oil inventories include expenditures incurred to produce, upgrade and transport the product to the storage facilities and include operating, depletion and depreciation expenses and cash royalties.
Income taxes	'
	Income taxes
	Income taxes are recognized using the liability method, whereby deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the consolidated financial statement carrying amounts of existing assets and liabilities and their respective tax base, and operating loss and tax credit carry forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences and carryforwards are expected to be recovered or settled. Valuation allowances are provided if, after considering available evidence, it is not more likely than not that some or all of the deferred tax assets will be realized.
	The tax benefit from an uncertain tax position is recognized when it is more likely than not, based on the technical merits of the position, that the position will be sustained on examination by the taxing authorities. Additionally, the amount of the tax benefit recognized is the largest amount of benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. In evaluating whether a tax position has met the more-likely-than-not recognition threshold, the Company presumes that the position will be examined by the appropriate taxing authority that has full knowledge of all relevant information. The Company recognizes potential penalties and interest related to unrecognized tax benefits as a component of income tax expense.
Oil and gas properties	'
	Oil and gas properties
	The Company uses the full cost method of accounting for its investment in oil and natural gas properties as defined by the Securities and Exchange Commission (“SEC”). Under this method, the Company capitalizes all acquisition, exploration and development costs incurred for the purpose of finding oil and natural gas reserves, including salaries, benefits and other internal costs directly attributable to these activities. Costs associated with production and general corporate activities; however, are expensed as incurred. Interest costs related to unproved properties and properties under development are also capitalized to oil and natural gas properties. Separate cost centers are maintained for each country in which the Company incurs costs.
	The Company computes depletion of oil and natural gas properties on a quarterly basis using the unit-of-production method based upon production and estimates of proved reserve quantities. Future development costs related to properties with proved reserves are also included in the amortization base for computation of depletion. The costs of unproved properties are excluded from the amortization base until the properties are evaluated. The cost of exploratory dry wells is transferred to proved properties, and thus is subject to amortization, immediately upon determination that a well is dry in those countries where proved reserves exist.
	The Company performs a ceiling test calculation each quarter in accordance with SEC Regulation S-X Rule 4-10. In performing its quarterly ceiling test, the Company limits, on a country-by-country basis, the capitalized costs of proved oil and natural gas properties, net of accumulated depletion and deferred income taxes, to the estimated future net cash flows from proved oil and natural gas reserves discounted at 10%, net of related tax effects, plus the lower of cost or fair value of unproved properties included in the costs being amortized. If such capitalized costs exceed the ceiling, the Company will record a write-down to the extent of such excess as a non-cash charge to net income. Any such write-down will reduce earnings in the period of occurrence and results in a lower DD&A rate in future periods. A write-down may not be reversed in future periods even though higher oil and natural gas prices may subsequently increase the ceiling.
	The Company calculates future net cash flows by applying the unweighted average of prices in effect on the first day of the month for the preceding 12-month period, adjusted for location and quality differentials. Such prices are utilized except where different prices are fixed and determinable from applicable contracts for the remaining term of those contracts.
	Unproved properties are not depleted pending the determination of the existence of proved reserves. Costs are transferred into the depletable base on an ongoing basis as the properties are evaluated and proved reserves are established or impairment is determined. Unproved properties are evaluated quarterly to ascertain whether impairment has occurred. This evaluation considers, among other factors, seismic data, requirements to relinquish acreage, drilling results and activity, remaining time in the commitment period, remaining capital plans, and political, economic, and market conditions. During any period in which factors indicate an impairment, the cumulative costs incurred to date for such property are transferred to the full cost pool and are then subject to depletion. For countries where a reserve base has not yet been established, the impairment is charged to earnings.
	In exploration areas, related geological and geophysical (“G&G”) costs are capitalized in unproved property and evaluated as part of the total capitalized costs associated with a property. G&G costs related to development projects are recorded in proved properties and therefore subject to depletion as incurred.
	Gains and losses on the sale or other disposition of oil and natural gas properties are not recognized, unless the gain or loss would significantly alter the relationship between capitalized costs and proved reserves of oil and natural gas attributable to a country.
Asset retirement obligation	'
	Asset retirement obligation
	The Company records an estimated liability for future costs associated with the abandonment of its oil and gas properties including the costs of reclamation of drilling sites. The Company records the fair value of a liability for a legal obligation to retire an asset in the period in which the liability is incurred with an offsetting increase to the related oil and gas properties. 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. 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. The accretion of the asset retirement obligation and amortization of the asset retirement cost are included in DD&A. If estimated future costs of an asset retirement obligation change, an adjustment is recorded to both the asset retirement obligation and oil and gas properties. Revisions to the estimated asset retirement obligation can result from changes in retirement cost estimates, revisions to estimated inflation rates and changes in the estimated timing of abandonment.
Other capital assets	'
	Other capital assets
	Other capital assets, including additions and replacements, are recorded at cost upon acquisition and include furniture, fixtures and leasehold improvement, computer equipment and automobiles. Depreciation is provided using the declining-balance method at a 30% annual rate for furniture and fixtures, computer equipment and automobiles. Leasehold improvements are depreciated on a straight-line basis over the shorter of the estimated useful life and the term of the related lease. The cost of repairs and maintenance is charged to expense as incurred.
Goodwill	'
	Goodwill
	Goodwill represents the excess of the aggregate of the consideration transferred over the net identifiable assets acquired and liabilities assumed. The Company assesses qualitative factors annually, or more frequently if necessary, to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount and whether it is necessary to perform the two-step goodwill impairment test. The impairment test requires allocating goodwill and certain other assets and liabilities to assigned reporting units. The fair value of each reporting unit is estimated and compared with the net book value of the reporting unit. If the estimated fair value of the reporting unit is less than the net book value, including goodwill, then the goodwill is written down to the implied fair value of the goodwill through a charge to expense. Because quoted market prices are not available for the Company’s reporting units, the fair values of the reporting units are estimated based upon estimated future cash flows of the reporting unit.
Revenue Recognition	'
	Revenue recognition
	Revenue from the production of oil and natural gas is recognized when the customer has taken title and has assumed the risks and rewards of ownership, prices are fixed or determinable, the sale is evidenced by a contract and collection of the revenue is reasonably assured.
	On February 1, 2012, the sales point for the Company’s Colombian oil sales to a significant customer in the Putumayo Basin changed. Gran Tierra’s customer, Ecopetrol S.A. (“Ecopetrol”), now takes title at the Port of Tumaco on the Pacific coast of Colombia rather than at the entry into the Ecopetrol-operated Trans-Andean oil pipeline (“the OTA pipeline”) at the Orito Station in the Putumayo Basin. In Colombia, the Company has other sales contracts where the sales point is the purchaser's facilities or when oil is loaded into a truck at Gran Tierra's loading facility or an export tanker.
	In Argentina, Gran Tierra transports oil from the field to the customer’s refinery or the oil terminal by pipeline or truck, where title is transferred. For the Company’s gas sales in Argentina, Gran Tierra’s customers take title when the gas is transferred to their pipeline. In Brazil, Gran Tierra transports product from the field to the customer’s station by truck, where title is transferred.
	Revenue represents the Company’s share and is recorded net of royalty payments to governments and other mineral interest owners.
Share-based compensation	'
	Stock-based compensation
	The Company grants time-vested restricted stock units ("RSUs") to officers, employees and consultants. RSUs entitle the holder to receive, at the option of the Company, either the underlying number of shares of the Company's Common Stock upon vesting of such shares or a cash payment equal to the value of the underlying shares. The Company expects its practice will be to settle RSUs in cash and, therefore, RSUs are accounted for as liability instruments. Compensation expense for RSUs granted is based on the estimated fair value, which is determined using the closing share price, at each reporting date, and the expense, net of estimated forfeitures, is recognized over the requisite service period using the accelerated method, with a corresponding change to liabilities. An adjustment is made to compensation expense for any difference between the estimated forfeitures and the actual forfeitures related to vested awards.
	Additionally, the Company grants options to purchase shares of Common Stock to certain directors, officers, employees and consultants. The Company follows the fair-value based method of accounting for stock options granted. Compensation expense for options granted is based on the estimated fair value, using the Black-Scholes option pricing model, at the time of grant and the expense, net of estimated forfeitures, is recognized over the requisite service period using the accelerated method. An adjustment is made to compensation expense for any difference between the estimated forfeitures and the actual forfeitures related to vested awards. The Company uses historical data to estimate option exercises, expected term and employee departure behavior used in the Black-Scholes option pricing model. Expected volatilities used in the fair value estimate are based on historical volatility of the Company’s shares. The risk-free rate for periods within the expected term of the stock options is based on the U.S. Treasury yield curve in effect at the time of grant.
	Stock-based compensation expense relating to RSUs and stock options is capitalized as part of oil and natural gas properties or expensed as part of operating expenses or general and administrative (“G&A”) expenses, as appropriate.
	Warrants
	The Company issued warrants (“Replacement Warrants”) in connection with its acquisition of Petrolifera Petroleum Limited (“Petrolifera”) in March 2011 (Note 3). The Replacement Warrants expired unexercised during August 2011. These warrants were derivative financial instruments and were recognized at fair value in the consolidated balance sheet as a current liability and as part of the consideration paid for the acquisition. The Company determined the fair value of warrants issued using the Black-Scholes option pricing model.
Foreign currency translations	'
	Foreign currency translation
	The functional currency of the Company, including its subsidiaries, is the United States dollar. Monetary items are translated into the reporting currency at the exchange rate in effect at the balance sheet date and non-monetary items are translated at historical exchange rates. Revenue and expense items are translated in a manner that produces substantially the same reporting currency amounts that would have resulted had the underlying transactions been translated on the dates they occurred.
	Depreciation or amortization of assets is translated at the historical exchange rates similar to the assets to which they relate.
	Gains and losses resulting from foreign currency transactions, which are transactions denominated in a currency other than the entity’s functional currency, are recognized in net income.
Net income per share	'
	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.
Adopted and Recently Issued Accounting Pronouncements	'
	Recently Issued 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 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The implementation of this update is not expected to materially impact the Company’s consolidated financial position, results of operations or 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 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The implementation of this update is not expected to materially impact the Company’s consolidated financial position, results of operations or cash flows or disclosure.

Business_Combinations_Tables

Business Combinations (Tables)	12 Months Ended
	Dec. 31, 2013
Business Combinations [Abstract]	'
Schedule of Purchase Price Allocation	'
	The following table shows the allocation of the consideration transferred based on the fair values of the assets and liabilities acquired:
	(Thousands of U.S. Dollars)
	Consideration Transferred:
	Cash	$	35,495
	Fair value of contingent consideration payable	1,061
		$	36,556
	Allocation of Consideration Transferred:
	Oil and gas properties
	Proved	$	24,107
	Unproved	12,859
	Asset retirement obligation	(410		)
		$	36,556
Fair Value of Warrants as Part of Consideration for Acquisition	'
	The fair value of the Replacement Warrants was estimated on the Acquisition Date using the Black-Scholes option pricing model with the following assumptions:
	Exercise price (CDN dollars per warrant)	$	9.67
	Risk-free interest rate	1.3		%
	Expected life	0.45 years
	Volatility	44		%
	Expected annual dividend per share	Nil
	Estimated fair value per warrant (CDN dollars)	$	0.32
Allocation of Consideration Transferred Based on Fair Values	'
	The following table shows the allocation of the consideration transferred based on the fair values of the assets and liabilities acquired:
	(Thousands of U.S. Dollars)
	Consideration Transferred:
	Shares of Common Stock issued net of share issue costs	$	141,690
	Replacement warrants	1,354
		$	143,044
	Allocation of Consideration Transferred:
	Oil and gas properties
	Proved	$	58,457
	Unproved	161,278
	Other long-term assets	4,417
	Net working capital (including cash acquired of $7.7 million and accounts receivable of $6.4 million)	(17,223		)
	Asset retirement obligation	(4,901		)
	Bank debt	(22,853		)
	Other long-term liabilities	(14,432		)
	Gain on acquisition	(21,699		)
		$	143,044
Pro Forma Information	'
	Pro forma results for the year ended December 31, 2011, are shown below, as if the acquisition had occurred on January 1, 2010. Pro forma results are not indicative of actual results or future performance.
		Year Ended December 31,
	(Unaudited, thousands of U.S. Dollars, except per share amounts)	2011
	Revenue and other income	$	606,602
	Net income	$	94,094
	Net income per share - basic	$	0.34
	Net income per share - diluted	$	0.33

Segment_and_Geographic_Reporti1

Segment and Geographic Reporting (Tables)	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Reportable Geographic Segments	'
	The following tables present information on the Company’s reportable segments and other activities:
		Year Ended December 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	$	624,410	$	73,495		$	—		$	22,545		$	—		$	720,450
	Interest income	623		1,015			27			909			619			3,193
	DD&A expenses	184,697		64,295			362			16,761			1,031			267,146
	DD&A - per unit of production	27.23		58.18			—			70.12			—			32.87
	Income (loss) before income taxes	336,179		(47,378		)	(7,067		)	(2,650		)	(17,248		)	261,836
	Segment capital expenditures (1)	188,547		19,503			82,954			23,039			775			314,818
		Year Ended December 31, 2012
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Argentina			Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	493,615	$	79,642		$	—		$	9,852		$	—		$	583,109
	Interest income	667		355			49			607			400			2,078
	DD&A expenses	122,055		31,466			1,234			26,300			982			182,037
	DD&A - per unit of production	25.37		24.74			—			259.88			—			29.44
	Income (loss) before income taxes	244,474		1,060			(5,493		)	(24,543		)	(18,135		)	197,363
	Segment capital expenditures (1)	153,331		40,653			62,869			55,239			1,084			313,176
		Year Ended December 31, 2011
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Argentina			Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	543,999	$	48,016		$	—		$	4,176		$	—		$	596,191
	Interest income	492		66			140			84			434			1,216
	DD&A expenses	141,133		45,506			42,035			1,819			742			231,235
	DD&A - per unit of production	26.17		49.61			—			42.25			—			36.39
	Income (loss) before income taxes	313,516		(32,635		)	(46,249		)	(3,878		)	3,493			234,247
	Segment capital expenditures (1)	202,551		36,289			36,224			50,836			1,747			327,647
	(1) In 2013, segment capital expenditures are net of proceeds of: $54.0 million relating to termination of a farm-in agreement in Brazil; $4.1 million relating to the Company's assumption of the remaining 50% working interest in the Santa Victoria Block in Argentina; and $1.5 million relating to the Company's sale of its 15% working interest in the Mecaya Block in Colombia (Note 6). In 2012, the Company paid $35.5 million and recorded $1.1 million of contingent consideration in connection with the acquisition of the remaining 30% working interest in four blocks in Brazil (Note 3). In 2011, amounts are net of proceeds from the farm-out of a 50% working interest in the Santa Victoria Block and the sale of a blow-out preventer, both in Argentina (Note 6). In 2011, the Company also completed its acquisition of all the issued and outstanding common shares and warrants of Petrolifera (Note 3).
Long-lived Assets by Geographical Area	'
		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
	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
		As at December 31, 2012
	(Thousands of U.S. Dollars)	Colombia		Argentina			Peru			Brazil			All Other			Total
	Property, plant and equipment	$	840,027	$	138,768		$	95,940		$	127,394		$	3,297		$	1,205,426
	Goodwill	102,581		—			—			—			—			102,581
	Other assets	222,220		47,038			10,880			8,498			136,232			424,868
	Total Assets	$	1,164,828	$	185,806		$	106,820		$	135,892		$	139,529		$	1,732,875

Accounts_Receivable_and_Invent1

Accounts Receivable and Inventory (Tables)	12 Months Ended
	Dec. 31, 2013
Receivables [Abstract]	'
Schedule of Accounts Receivable	'
	Accounts Receivable
		As at December 31,
	(Thousands of U.S. Dollars)	2013		2012
	Trade	$	46,113	$	116,434
	Other	3,590		3,410
		$	49,703	$	119,844

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2013
Property, Plant and Equipment [Abstract]	'
Schedule of Property, Plant and Equipment	'
	Property, Plant and Equipment
		As at December 31, 2013								As at December 31, 2012
	(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	$	1,799,544		$	(1,005,475	)	$	794,069	$	1,562,477	$	(749,230	)	$	813,247
	Unproved	456,001			—			456,001		383,414		—			383,414
		2,255,545			(1,005,475		)	1,250,070		1,945,891		(749,230		)	1,196,661
	Furniture and fixtures and leasehold improvements	8,919			(6,568		)	2,351		7,575		(5,093		)	2,482
	Computer equipment	14,786			(7,605		)	7,181		10,971		(5,248		)	5,723
	Automobiles	1,381			(811		)	570		1,376		(816		)	560
	Total Property, Plant and Equipment	$	2,280,631		$	(1,020,459	)	$	1,260,172	$	1,965,813	$	(760,387	)	$	1,205,426
Schedule of capitalized general and administrative expenses	'
	The amounts of G&A and stock-based compensation capitalized in each of the Company's cost centers during the years ended December 31, 2013, 2012 and 2011, respectively, were as follows:
		Year Ended December 31, 2013
	(Thousands of U.S. Dollars)	Colombia			Argentina			Peru		Brazil		Total
	Capitalized G&A, including stock-based compensation	$	21,415		$	3,423		$	7,896	$	7,220	$	39,954
	Capitalized stock-based compensation	921			128			669		718		2,436
		Year Ended December 31, 2012
	(Thousands of U.S. Dollars)	Colombia			Argentina			Peru		Brazil		Total
	Capitalized G&A, including stock-based compensation	$	15,054		$	4,605		$	4,761	$	3,844	$	28,264
	Capitalized stock-based compensation	481			354			—		275		1,110
		Year Ended December 31, 2011
	(Thousands of U.S. Dollars)	Colombia			Argentina			Peru		Brazil		Total
	Capitalized G&A, including stock-based compensation	$	7,996		$	3,189		$	1,183	$	1,985	$	14,353
	Capitalized stock-based compensation	456			266			—		234		956
Summary of Oil and Natural Gas Properties	'
	The following is a summary of Gran Tierra’s oil and natural gas properties not subject to depletion as at December 31, 2013:
		Costs Incurred in
	(Thousands of U.S. Dollars)	2013			2012			2011		Prior to 2011		Total
	Acquisition costs - Colombia	$	—		$	—		$	3,900	$	127,842	$	131,742
	Acquisition costs - Argentina	(4,088		)	—			14,889		—		10,801
	Acquisition costs - Peru	—			5,400			23,423		2,000		30,823
	Acquisition costs - Brazil	—			12,802			22,668		—		35,470
	Exploration costs - Colombia	4,965			16,092			7,225		16,064		44,346
	Exploration costs - Argentina	204			(588		)	2,595		5,226		7,437
	Exploration costs - Peru	82,311			58,286			6,019		—		146,616
	Exploration costs - Brazil	14,106			17,128			17,532		—		48,766
	Total oil and natural gas properties not subject to depletion	$	97,498		$	109,120		$	98,251	$	151,132	$	456,001

Share_Capital_Tables

Share Capital (Tables)	12 Months Ended
	Dec. 31, 2013
Stockholders' Equity Note [Abstract]	'
Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]	'
	The amounts recognized for stock-based compensation were as follows:
	(Thousands of U.S. Dollars)		Year Ended December 31,
			2013				2012				2011
	Compensation costs for stock options		$	8,418			$	13,116			$	13,723
	Compensation costs for RSUs		2,936				—				—
			11,354				13,116				13,723
	Less: stock-based compensation costs capitalized		(2,436		)		(1,110		)		(956		)
	Total stock-based compensation expense		$	8,918			$	12,006			$	12,767
Assumptions used to estimate the fair value of stock option awards	'
	The fair value of each stock option award is estimated on the date of grant using the Black-Scholes option pricing model based on assumptions noted in the following table:
		Year Ended December 31,
		2013		2012		2011
	Dividend yield (per share)	Nil		Nil		Nil
	Volatility	42% to 54%		59% to 75%		75% to 81%
	Weighted average volatility	53	%	75	%	80	%
	Risk-free interest rate	0.3% to 0.7%		0.3% to 0.4%		0.4% to 1.4%
	Expected term	4-5 years		4-6 years		4-6 years
Stock options outstanding	'
	The following table provides information about stock option and RSU activity for the year ended December 31, 2013:
		RSUs		Options
		Number of Outstanding Share Units		Number of Outstanding Options			Weighted Average Exercise Price $/Option
	Balance, December 31, 2012	—		15,399,662			5.11
	Granted	966,320		2,121,375			6.29
	Exercised	—		(1,306,317	)		(2.89	)
	Forfeited	(44,275	)	(396,003	)		(7.01	)
	Expired	—		(150,259	)		(6.25	)
	Balance, December 31, 2013	922,045		15,668,458			5.41
	Exercisable, at December 31, 2013			10,372,602			4.87
	Vested, or expected to vest, at December 31, 2013, through the life of the options			15,142,311			5.37
Weighted average shares outstanding	'
	Weighted Average Shares Outstanding
			Year Ended December 31,
			2013			2012			2011
	Weighted average number of common and exchangeable shares outstanding		282,808,497			280,741,255			273,491,564
	Shares issuable pursuant to warrants		—			175,061			2,708,183
	Shares issuable pursuant to stock options		12,041,260			5,879,929			5,143,498
	Shares assumed to be purchased from proceeds of stock options		(8,721,860	)		(2,623,991	)		(56,243	)
	Weighted average number of diluted common and exchangeable shares outstanding		286,127,897			284,172,254			281,287,002

Asset_Retirement_Obligation_Ta

Asset Retirement Obligation (Tables)	12 Months Ended
	Dec. 31, 2013
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:
		Year Ended December 31,
	(Thousands of U.S. Dollars)	2013			2012
	Balance, beginning of year	$	18,292		$	12,669
	Settlements	(2,068		)	(404		)
	Liability incurred	2,623			5,190
	Liability assumed in a business combination (Note 3)	—			410
	Foreign exchange	(25		)	45
	Accretion	1,279			998
	Revisions in estimated liability	1,872			(616		)
	Balance, end of year	$	21,973		$	18,292
	Asset retirement obligation - current	$	518		$	28
	Asset retirement obligation - long-term	21,455			18,264
	Balance, end of year	$	21,973		$	18,292

Taxes_Tables

Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
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:
		Year Ended December 31,
	(Thousands of U.S. Dollars)	2013			2012			2011
	Income (loss) before income taxes
	United States	$	(13,566	)	$	(13,918	)	$	4,984
	Foreign	275,402			211,281			229,263
		261,836			197,363			234,247
		35		%	35		%	35		%
	Income tax expense expected	91,643			69,077			81,986
	Foreign currency translation adjustments	(2,978		)	5,473			(417		)
	Impact of foreign taxes	(1,287		)	(1,833		)	3,890
	Stock-based compensation	2,859			3,982			4,013
	Increase in valuation allowance	39,028			6,709			36,815
	Branch and other foreign loss pick-up	(2,362		)	(3,809		)	(14,363		)
	Non-deductible third party royalty in Colombia	11,073			11,938			8,525
	Non-taxable gain on acquisition	—			—			(7,595		)
	Other permanent differences (1)	(2,428		)	6,167			(5,524		)
	Total income tax expense	$	135,548		$	97,704		$	107,330
	Current income tax expense
	United States	$	1,250		$	1,233		$	1,029
	Foreign	163,797			70,197			134,986
		165,047			71,430			136,015
	Deferred income tax expense (recovery)
	United States	—			—			—
	Foreign	(29,499		)	26,274			(28,685		)
		(29,499		)	26,274			(28,685		)
	Total income tax expense	$	135,548		$	97,704		$	107,330
Deferred tax assets and liabilities	'
		As at December 31,
	(Thousands of U.S. Dollars)	2013			2012
	Deferred Tax Assets
	Tax benefit of operating loss carryforwards	$	47,154		$	51,920
	Tax basis in excess of book basis	59,168			22,519
	Foreign tax credits and other accruals	34,894			30,926
	Tax benefit of capital loss carryforwards	4,769			4,779
	Deferred tax assets before valuation allowance	145,985			110,144
	Valuation allowance	(142,322		)	(106,226		)
		$	3,663		$	3,918
	Deferred tax assets - current	$	2,256		$	2,517
	Deferred tax assets - long-term	1,407			1,401
		3,663			3,918
	Deferred tax liabilities - current	(1,193		)	(337		)
	Deferred tax liabilities - long-term	(177,082		)	(225,195		)
		(178,275		)	(225,532		)
	Net Deferred Tax Liabilities	$	(174,612	)	$	(221,614	)
Summary of Other Tax Carryforwards	'
	Changes in the Company's unrecognized tax benefit are as follows:
		Year Ended December 31,
		2013			2012			2011
	(Thousands of U.S. Dollars)
	Unrecognized tax benefit, beginning of year	$	21,800		$	20,500		$	4,175
	Increases for positions relating to prior year	3,200			1,300			585
	Additions to tax position related to the current year	—			—			15,740
	Decreases due to lapse of statute of limitations	(1,500		)	—			—
	Settlements	(1,400		)	—			—
	Unrecognized tax benefit, end of year	$	22,100		$	21,800		$	20,500

Accounts_Payable_and_Accrued_L1

Accounts Payable and Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2013
Payables and Accruals [Abstract]	'
Schedule of Accounts Payable and Accrued Liabilities	'
		As at December 31,
	(Thousands of U.S. Dollars)	2013		2012
	Trade	$	97,947	$	103,720
	Royalties	14,969		17,607
	VAT and withholding tax	24,882		28,169
	Employee compensation	16,525		13,178
	Other	7,644		6,007
		$	161,967	$	168,681

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Contractual Obligations Future Lease Payments	'
	The following is a schedule by year of purchase obligations, future minimum payments for firm agreements and leases that have initial or remaining lease terms in excess of one year as of December 31, 2013:
		Year ending December 31
		Total		2014		2015		2016		2017		2018		Thereafter
	(Thousands of U.S. Dollars)
	Oil transportation services	$	52,339	$	23,261	$	10,635	$	3,812	$	3,812	$	3,812	$	7,007
	Drilling and G&G	56,143		55,806		337		—		—		—		—
	Completions	48,500		26,544		14,289		7,667		—		—		—
	Facility construction	19,446		18,748		698		—		—		—		—
	Operating leases	3,949		2,690		989		163		26		16		65
	Software and telecommunication	1,992		1,824		137		31		—		—		—
	Consulting	1,225		937		288		—		—		—		—
		$	183,594	$	129,810	$	27,373	$	11,673	$	3,838	$	3,828	$	7,072

Financial_Instruments_Fair_Val1

Financial Instruments, Fair Value Measurements and Credit Risk (Tables)	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Fair value of contingent consideration	'
	The fair value of the contingent consideration and this contingent liability at December 31, 2013 and December 31, 2012 were as follows:
		As at December 31,
	(Thousands of U.S. Dollars)	2013		2012
	Contingent consideration (Note 3)	$	1,061	$	1,061
	Contingent liability (Note 11)	$	4,400	$	—

Significant_Accounting_Policie2

Significant Accounting Policies Narrative (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2008	Dec. 31, 2006
			Solana [Member]	Argosy [Member]
Business Acquisition [Line Items]	'	'	'	'
Depreciation rate for other capital assets	30.00%	'	'	'
Allowance for doubtful accounts receivable	$0	$0	'	'
Goodwill (Note 2)	$102,581	$102,581	$87,600	$15,000

Purchase_Price_Allocation_Deta

Purchase Price Allocation (Details) (USD $)	0 Months Ended	12 Months Ended			0 Months Ended
	Mar. 17, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 18, 2011	Oct. 08, 2012
					Petrolifera [Member]	Block-Brazil [Member]
Business Acquisition [Line Items]	'	'	'	'	'	'
Cash	'	'	'	'	'	$35,495,000
Fair value of contingent consideration payable	'	1,061,000	1,061,000	'	'	1,061,000
Shares of Common Stock issued net of share issue costs	'	'	'	'	141,690,000	'
Replacement warrants	'	'	'	'	1,354,000	'
Total Consideration	'	'	'	'	143,044,000	36,556,000
Proved	'	'	'	'	'	24,107,000
Unproved	'	'	'	'	'	12,859,000
Asset retirement obligation	'	'	'	'	'	-410,000
Proved	'	'	'	'	58,457,000	'
Unproved	'	'	'	'	161,278,000	'
Other long-term assets	'	'	'	'	4,417,000	'
Net working capital (including cash acquired of $7.7 million and accounts receivable of $6.4 million)	'	'	'	'	-17,223,000	'
Asset retirement obligation	'	'	'	'	-4,901,000	'
Bank debt	'	'	'	'	-22,853,000	'
Other long-term liabilities	'	'	'	'	-14,432,000	'
Gain on acquisition	'	'	'	'	-21,699,000	'
Cash acquired from acquisition	0	0	0	7,747,000	7,700,000	'
Receivables	'	'	'	'	$6,400,000	'

Black_Scholes_Assumptions_Deta

Black Scholes Assumptions (Details) (Petrolifera [Member], CAD)	0 Months Ended
	Mar. 18, 2011
Petrolifera [Member]	'
Business Acquisition [Line Items]	'
Exercise price of common warrants issued by acquirer in business acquisition (in Canadian dollars per share)	9.67
Risk-free interest rate (in hundredths)	1.30%
Expected life (in years)	'5 months 12 days
Volatility (in hundredths)	44.00%
Expected annual dividend per share	'0
Fair value per warrant (in Canadian dollars per share)	0.32

Pro_Forma_Results_Details

Pro Forma Results (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2011
Business Combinations [Abstract]	'
Revenue and other income	$606,602
Net income	$94,094
Net income per share - basic	$0.34
Net income per share - diluted	$0.33

Business_Combinations_Narrativ

Business Combinations Narrative (Details)

0 Months Ended

9 Months Ended

12 Months Ended

0 Months Ended

5 Months Ended

9 Months Ended

12 Months Ended

0 Months Ended

0 Months Ended

Mar. 17, 2011

Mar. 18, 2011

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Aug. 28, 2011

Mar. 31, 2011

Mar. 28, 2011

Mar. 17, 2011

Mar. 18, 2011

Aug. 05, 2011

Dec. 31, 2011

Dec. 31, 2011

Dec. 31, 2011

Mar. 18, 2011

Oct. 08, 2012

Jan. 20, 2012

Aug. 26, 2010

Mar. 18, 2011

Mar. 18, 2011

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Petrolifera [Member]

Petrolifera [Member]

Petrolifera [Member]

Petrolifera [Member]

Petrolifera [Member]

Petrolifera [Member]

Petrolifera [Member]

Petrolifera [Member]

Petrolifera [Member]

Petrolifera [Member]

Block-Brazil [Member]

Block-Brazil [Member]

Block-Brazil [Member]

MAV IA 1 & 2 [Member]

Petrolifera Reserve Backed Line of Credit [Member]

USD ($)

CAD

USD ($)

USD ($)

USD ($)

USD ($)

CAD

CAD

USD ($)

block

Foreign Line of Credit [Member]

Foreign Line of Credit [Member]

block

Petrolifera [Member]

Petrolifera [Member]

well

USD ($)

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Participating interest percentage oil and gas property, remaining percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30.00%

30.00%

'

'

'

Number of blocks

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4

'

'

Number of producing blocks

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

'

'

'

Number of producing wells

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3

'

'

'

'

Cash paid for acquisition

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$28,000,000

'

'

'

'

Purchase price adjustment for share of interm costs before regulatory approval

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

7,500,000

'

'

'

'

Additional contingent consideration, maximum

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,000,000

'

'

'

'

Fair value of contingent consideration payable

'

'

'

1,061,000

1,061,000

'

'

'

'

'

'

'

'

'

'

'

1,061,000

'

'

'

'

Business acquisition meeting date

'

'

'

'

'

'

'

'

'

'March 17, 2011

'

'

'

'

'

'

'

'

'

'

'

Business acquisition effective date of acquisition

'

'

'

'

'

'

'

'

'

'

18-Mar-11

'

'

'

'

'

'

'

'

'

'

Shares of acquirer's warrants issued to holder of each share of acquired entity (in shares)

'

'

'

'

'

'

'

'

'

'

0.1241

'

'

'

'

'

'

'

'

'

'

Shares of acquirer's warrants issued to holder of each common stock warrant of acquired entity (in shares)

'

'

'

'

'

'

'

'

'

'

0.1241

'

'

'

'

'

'

'

'

'

'

Exercise price of common warrants issued by acquirer in business acquisition (in Canadian dollars per share)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

9.67

'

'

'

'

'

Expiration date of stock warrants issued in business acquisition

'

'

'

'

'

'

28-Aug-11

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business acquisition number of shares issued

'

'

'

'

'

'

'

'

'

'

18,075,247

'

'

'

'

'

'

'

'

'

'

Par value of common shares issued in acquisition (in dollars per share)

'

$0.00

'

$0.00

$0.00

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Replacement Warrants issued in business acquisition (in shares)

'

'

'

'

'

'

'

4,125,036

'

'

'

'

'

'

'

'

'

'

'

'

'

Business acquisition acquired entity security holders ownership in new entity (in hundredths)

'

'

'

'

'

'

'

'

'

'

6.60%

'

'

'

'

'

'

'

'

'

'

Business acquisition acquirer's security holders ownership in new entity (in hundredths)

'

'

'

'

'

'

'

'

'

'

93.40%

'

'

'

'

'

'

'

'

'

'

Total consideration for acquisition

'

'

'

'

'

'

'

'

'

'

143,044,000

'

'

'

'

'

36,556,000

'

'

'

'

Fair value assumptions methodology used

'

'

'

'

'

'

'

'

'

'

' fair value of the Replacement Warrants was estimated on the Acquisition Date using the Black-Scholes option pricing model with the following assumptions

'

'

'

'

'

'

'

'

'

'

Gain arising from fair value of replacement warrant expiration

'

'

'

'

'

1,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Gain on acquisition excluded from pro forma results

'

21,700,000

'

'

'

21,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value assigned for Petrolifera's notes

'

'

'

'

'

'

'

'

'

'

22,500,000

'

'

'

'

'

'

'

'

'

'

Face value of asset back commercial paper given in exchange

'

'

'

'

'

'

'

'

'

'

31,300,000

'

'

'

'

'

'

'

'

'

'

Proceeds on sale of asset backed commercial paper

'

'

'

0

0

22,679,000

'

'

22,700,000

'

'

'

'

'

'

'

'

'

'

'

'

Gain (loss) on derivative instruments, net, pretax

'

'

'

0

0

1,522,000

'

'

'

'

'

'

'

1,500,000

'

'

'

'

'

'

'

ABCP line of credit

'

'

'

'

'

'

'

'

'

'

'

'

'

'

23,200,000

'

'

'

'

'

'

Repayment of debt from cash flow

'

54,100,000

'

'

'

'

'

'

'

'

'

'

'

'

22,500,000

'

'

'

'

'

'

Second line of credit

'

'

'

'

'

'

'

'

'

5,000,000

'

'

'

'

'

'

'

'

'

'

'

Cash acquired from acquisition

0

'

'

0

0

7,747,000

'

'

'

'

7,700,000

'

'

'

'

'

'

'

'

'

'

Line of credit facility collateral

'

'

'

'

'

'

'

'

'

'master asset vehicles Classes 1 & 2 (“MAV IA 1 & 2”) notes with a face value of $6.6 million

'

'

'

'

'

'

'

'

'

'

'

Reserve-backed credit facility assumed in acquisition

'

'

'

'

'

'

'

'

'

'

31,300,000

'

'

'

'

'

'

'

'

'

'

Description of variable rate basis

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'LIBOR

Basis spread on variable rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

8.25%

Line of credit facility interest expense accrual on reserved credit facility, period

'

'

'

'

'

'

'

'

'

'

'

'140 days

'

'

'

'

'

'

'

'

'

Line of credit facility periodic interest payment

'

'

'

'

'

'

'

'

'

'

'

1,600,000

'

'

'

'

'

'

'

'

'

Gain on acquisition

'

'

'

'

'

'

'

'

'

'

21,699,000

'

'

'

'

'

'

'

'

'

'

Revenue and other income

'

'

'

'

'

'

'

'

'

'

'

'

32,500,000

'

'

'

'

'

'

'

'

Business acquisition, transaction costs

'

'

4,400,000

'

'

4,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Loss after tax from the acquisition in the period since the acquisition date

'

'

8,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Face Amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$6,600,000

'

Segment_and_Geographic_Reporti2

Segment and Geographic Reporting (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Disclosure on Geographic Areas, Description of Revenue from External Customers	'		'	'
Oil and natural gas sales	$720,450		$583,109	$596,191
Interest income	3,193		2,078	1,216
DD&A expenses	267,146		182,037	231,235
DD&A - per unit of production	32.87		29.44	36.39
Income (loss) before income taxes	261,836		197,363	234,247
Segment capital expenditures	314,818	[1]	313,176	327,647
Colombia [Member]	'		'	'
Disclosure on Geographic Areas, Description of Revenue from External Customers	'		'	'
Oil and natural gas sales	624,410		493,615	543,999
Interest income	623		667	492
DD&A expenses	184,697		122,055	141,133
DD&A - per unit of production	27.23		25.37	26.17
Income (loss) before income taxes	336,179		244,474	313,516
Segment capital expenditures	188,547		153,331	202,551
Argentina [Member]	'		'	'
Disclosure on Geographic Areas, Description of Revenue from External Customers	'		'	'
Oil and natural gas sales	73,495		79,642	48,016
Interest income	1,015		355	66
DD&A expenses	64,295		31,466	45,506
DD&A - per unit of production	58.18		24.74	49.61
Income (loss) before income taxes	-47,378		1,060	-32,635
Segment capital expenditures	19,503		40,653	36,289
Peru [Member]	'		'	'
Disclosure on Geographic Areas, Description of Revenue from External Customers	'		'	'
Oil and natural gas sales	0		0	0
Interest income	27		49	140
DD&A expenses	362		1,234	42,035
DD&A - per unit of production	0		0	0
Income (loss) before income taxes	-7,067		-5,493	-46,249
Segment capital expenditures	82,954		62,869	36,224
Brazil [Member]	'		'	'
Disclosure on Geographic Areas, Description of Revenue from External Customers	'		'	'
Oil and natural gas sales	22,545		9,852	4,176
Interest income	909		607	84
DD&A expenses	16,761		26,300	1,819
DD&A - per unit of production	70.12		259.88	42.25
Income (loss) before income taxes	-2,650		-24,543	-3,878
Segment capital expenditures	23,039		55,239	50,836
All Other [Member]	'		'	'
Disclosure on Geographic Areas, Description of Revenue from External Customers	'		'	'
Oil and natural gas sales	0		0	0
Interest income	619		400	434
DD&A expenses	1,031		982	742
DD&A - per unit of production	0		0	0
Income (loss) before income taxes	-17,248		-18,135	3,493
Segment capital expenditures	$775		$1,084	$1,747
[1]	In 2013, segment capital expenditures are net of proceeds of: $54.0 million relating to termination of a farm-in agreement in Brazil; $4.1 million relating to the Company's assumption of the remaining 50% working interest in the Santa Victoria Block in Argentina; and $1.5 million relating to the Company's sale of its 15% working interest in the Mecaya Block in Colombia (Note 6). In 2012, the Company paid $35.5 million and recorded $1.1 million of contingent consideration in connection with the acquisition of the remaining 30% working interest in four blocks in Brazil (Note 3). In 2011, amounts are net of proceeds from the farm-out of a 50% working interest in the Santa Victoria Block and the sale of a blow-out preventer, both in Argentina (Note 6). In 2011, the Company also completed its acquisition of all the issued and outstanding common shares and warrants of Petrolifera (Note 3).

Segment_and_Geographic_Reporti3

Segment and Geographic Reporting Assets (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	$1,260,172	$1,205,426
Goodwill (Note 2)	102,581	102,581
Other assets	541,797	424,868
Total Assets	1,904,550	1,732,875
Colombia [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	850,359	840,027
Goodwill (Note 2)	102,581	102,581
Other assets	233,336	222,220
Total Assets	1,186,276	1,164,828
Argentina [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	94,366	138,768
Goodwill (Note 2)	0	0
Other assets	39,209	47,038
Total Assets	133,575	185,806
Peru [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	178,531	95,940
Goodwill (Note 2)	0	0
Other assets	24,240	10,880
Total Assets	202,771	106,820
Brazil [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	133,874	127,394
Goodwill (Note 2)	0	0
Other assets	24,477	8,498
Total Assets	158,351	135,892
All Other [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	3,042	3,297
Goodwill (Note 2)	0	0
Other assets	220,535	136,232
Total Assets	$223,577	$139,529

Segment_and_Geographic_Reporti4

Segment and Geographic Reporting Narrative (Details) (USD $)

12 Months Ended

3 Months Ended

1 Months Ended

12 Months Ended

0 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

0 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Sep. 30, 2013

Sep. 30, 2011

Mar. 31, 2011

Dec. 31, 2013

Oct. 08, 2012

Jan. 20, 2012

Aug. 26, 2010

Jun. 30, 2013

Dec. 31, 2013

Jun. 30, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Mar. 18, 2011

Brazil [Member]

Argentina [Member]

Argentina [Member]

Argentina [Member]

Block-Brazil [Member]

Block-Brazil [Member]

Block-Brazil [Member]

Santa Victoria Block [Member]

Santa Victoria Block [Member]

Mecaya Block [Member]

Mecaya Block [Member]

Colombia [Member]

Colombia [Member]

Colombia [Member]

Colombia [Member]

Colombia [Member]

Petrolifera [Member]

block

Argentina [Member]

Argentina [Member]

Colombia [Member]

Colombia [Member]

customer

Ecopetrol [Member]

Ecopetrol [Member]

Ecopetrol [Member]

Other Customer Number Two [Member]

Concentration Risk [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business acquisition effective date of acquisition

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

18-Mar-11

Proceeds from termination of farm-in agreement

'

'

'

$54,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from assumption of oil and gas property

'

'

'

'

'

'

'

'

'

'

4,100,000

'

'

'

'

'

'

'

'

'

Working interest assumed from partner

'

'

'

'

'

'

'

'

'

'

50.00%

50.00%

'

'

'

'

'

'

'

'

Proceeds from oil and gas properties (Note 6)

59,621,000

0

4,450,000

'

1,200,000

'

'

'

'

'

'

'

1,500,000

'

'

'

'

'

'

'

Working interest sold, percentage

'

'

'

'

'

'

'

'

'

'

'

'

15.00%

15.00%

'

'

'

'

'

'

Cash paid

'

'

'

'

'

'

'

35,495,000

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of contingent consideration payable

$1,061,000

$1,061,000

'

'

'

'

'

$1,061,000

'

'

'

'

'

'

'

'

'

'

'

'

Participating interest percentage oil and gas property, remaining percentage

'

'

'

'

'

'

'

30.00%

30.00%

'

'

'

'

'

'

'

'

'

'

'

Number of blocks

'

'

'

'

'

'

'

'

'

4

'

'

'

'

'

'

'

'

'

'

Participating Interest (in hundredths)

'

'

'

'

'

50.00%

50.00%

'

'

70.00%

'

'

'

'

'

'

'

'

'

'

Number of significant customers

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2

'

'

'

'

'

Sales to Ecopetrol, as a percentage of total revenue (in hundredths)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

41.00%

74.00%

87.00%

38.00%

'

Accounts_Receivable_and_Invent2

Accounts Receivable and Inventory (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Accounts receivable	$49,703,000	$119,844,000
Crude oil inventories	11,700,000	31,200,000
Supplies	2,000,000	2,300,000
Trade Accounts Receivable [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Accounts receivable	46,113,000	116,434,000
Other Accounts Receivable [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Accounts receivable	$3,590,000	$3,410,000

Property_Plant_and_Equipment_D

Property, Plant and Equipment (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'
Cost	$2,280,631	$1,965,813
Accumulated depletion, depreciation and impairment	-1,020,459	-760,387
Total Property, Plant and Equipment (Note 6)	1,260,172	1,205,426
Proved	794,069	813,247
Unproved oil and gas property full cost accounting	456,001	383,414
Proved [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Accumulated depletion, depreciation and impairment	-1,005,475	-749,230
Total Property, Plant and Equipment (Note 6)	794,069	813,247
Proved	1,799,544	1,562,477
Unproved [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Accumulated depletion, depreciation and impairment	0	0
Total Property, Plant and Equipment (Note 6)	456,001	383,414
Unproved oil and gas property full cost accounting	456,001	383,414
Oil and natural gas properties [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	2,255,545	1,945,891
Accumulated depletion, depreciation and impairment	-1,005,475	-749,230
Total Property, Plant and Equipment (Note 6)	1,250,070	1,196,661
Furniture and fixtures and leasehold improvements [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	8,919	7,575
Accumulated depletion, depreciation and impairment	-6,568	-5,093
Total Property, Plant and Equipment (Note 6)	2,351	2,482
Computer equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	14,786	10,971
Accumulated depletion, depreciation and impairment	-7,605	-5,248
Total Property, Plant and Equipment (Note 6)	7,181	5,723
Automobiles [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	1,381	1,376
Accumulated depletion, depreciation and impairment	-811	-816
Total Property, Plant and Equipment (Note 6)	$570	$560

Property_Plant_and_Equipment_A

Property, Plant and Equipment Amounts Capitalized by Cost Center (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'	'
Capitalized G&A, including stock-based compensation	$39,954	$28,264	$14,353
Capitalized stock-based compensation	2,436	1,110	956
Colombia [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Capitalized G&A, including stock-based compensation	21,415	15,054	7,996
Capitalized stock-based compensation	921	481	456
Argentina [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Capitalized G&A, including stock-based compensation	3,423	4,605	3,189
Capitalized stock-based compensation	128	354	266
Peru [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Capitalized G&A, including stock-based compensation	7,896	4,761	1,183
Capitalized stock-based compensation	669	0	0
Brazil [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Capitalized G&A, including stock-based compensation	7,220	3,844	1,985
Capitalized stock-based compensation	$718	$275	$234

Property_Plant_and_Equipment_C

Property, Plant and Equipment Costs Incurred for Acquisition, Exploration and Development (Details) (USD $)	12 Months Ended			91 Months Ended	127 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]	'	'	'	'	'
Total oil and natural gas properties not subject to depletion	$97,498	$109,120	$98,251	$151,132	$456,001
Colombia [Member]	'	'	'	'	'
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]	'	'	'	'	'
Acquisition costs	0	0	3,900	127,842	131,742
Exploration costs	4,965	16,092	7,225	16,064	44,346
Argentina [Member]	'	'	'	'	'
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]	'	'	'	'	'
Acquisition costs	-4,088	0	14,889	0	10,801
Exploration costs	204	-588	2,595	5,226	7,437
Peru [Member]	'	'	'	'	'
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]	'	'	'	'	'
Acquisition costs	0	5,400	23,423	2,000	30,823
Exploration costs	82,311	58,286	6,019	0	146,616
Brazil [Member]	'	'	'	'	'
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]	'	'	'	'	'
Acquisition costs	0	12,802	22,668	0	35,470
Exploration costs	$14,106	$17,128	$17,532	$0	$48,766

Property_Plant_and_Equipment_N

Property, Plant and Equipment Narrative (Details) (USD $)

1 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

12 Months Ended

0 Months Ended

1 Months Ended

1 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

Sep. 30, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Sep. 30, 2011

Mar. 31, 2011

Dec. 31, 2013

Dec. 31, 2011

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Jun. 05, 2012

Sep. 30, 2013

Mar. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Jun. 01, 2012

Oct. 08, 2012

Jan. 20, 2012

Aug. 26, 2010

Jun. 15, 2011

Sep. 30, 2011

Apr. 03, 2012

Sep. 30, 2011

Mar. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Jun. 30, 2013

Dec. 31, 2013

Jun. 30, 2013

Dec. 31, 2013

Jun. 30, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

farmout

Argentina [Member]

Argentina [Member]

Argentina [Member]

Argentina [Member]

Argentina [Member]

Colombia [Member]

Colombia [Member]

Colombia [Member]

Brazil [Member]

Brazil [Member]

Brazil [Member]

Brazil [Member]

Peru [Member]

Peru [Member]

Peru [Member]

Block-Peru [Member]

Block-Brazil [Member]

Block-Brazil [Member]

Block-Brazil [Member]

Block-Brazil [Member]

Block-BM-CAL-7 [Member]

Block-BM-CAL-7 [Member]

Block-BM-CAL-10 [Member]

Block-BM-CAL-10 [Member]

Minimum [Member]

Maximum [Member]

Santa Victoria Block [Member]

Santa Victoria Block [Member]

Mecaya Block [Member]

Mecaya Block [Member]

Brazil [Member]

Brazil [Member]

Brazil [Member]

Unproved [Member]

Unproved [Member]

Unproved [Member]

block

Argentina [Member]

Argentina [Member]

Colombia [Member]

Colombia [Member]

block

block

Block-BM-CAL-7 [Member]

Brazil [Member]

Property, Plant and Equipment [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Depreciation and depletion

'

$227,300,000

$168,000,000

$162,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Working interest assumed from partner

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

50.00%

50.00%

'

'

'

'

'

'

'

'

Proceeds from assumption of oil and gas property

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4,100,000

'

'

'

'

'

'

'

'

'

Proceeds from sale of a blow-out preventer

'

59,621,000

0

4,450,000

1,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,500,000

'

'

'

'

'

'

'

Valuation Allowance, Deferred Tax Asset, Change in Amount

'

36,100,000

'

'

'

'

30,800,000

'

'

'

'

'

'

'

2,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Working interest sold, percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

15.00%

15.00%

'

'

'

'

'

'

Number of blocks successfully bid

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3

'

'

'

'

'

Payments for signature bonus

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

14,400,000

'

'

'

'

'

Proceeds from termination of farm-in agreement

'

'

'

'

'

'

'

'

'

'

'

'

54,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Drilling costs for previously drilled oil exploration well

'

'

'

'

'

'

'

'

'

'

'

21,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Participating interest percentage oil and gas property, remaining percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

40.00%

30.00%

30.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Purchase consideration for oil and gas regulatory approval

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,400,000

'

'

'

40,100,000

'

700,000

'

23,800,000

'

'

'

'

'

'

'

'

'

'

'

'

Loss on contract termination

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,300,000

'

'

'

Farm out interest assigned (in hundredths)

'

'

'

'

'

50.00%

50.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

70.00%

'

10.00%

'

15.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of blocks

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of farmout agreements

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Exploration costs

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

51,400,000

Proceeds from divestiture of interest in joint venture

'

'

'

'

'

3,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Impairment of oil and gas properties

'

'

'

'

'

'

'

25,700,000

'

'

'

'

'

20,200,000

'

'

42,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Property, Plant and Equipment, Net

'

1,260,172,000

1,205,426,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

456,001,000

383,414,000

'

Number of Unproved Reserves Blocks

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4

'

'

'

'

Unproved assets by cost center

'

$456,000,000

$383,400,000

'

'

'

$18,200,000

'

$42,300,000

$176,100,000

$175,900,000

'

'

'

$84,200,000

$70,100,000

'

$177,500,000

$95,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Costs transferred to depletable base within 5 years

'

75.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Oil and Gas Property, Transfer of Costs to Depletable Base, Time Period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'5 years

'10 years

'

'

'

'

'

'

'

'

'

'

Black_Scholes_Option_Pricing_M

Black Scholes Option Pricing Model Assumptions (Details) (Stock Options [Member])	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Expected dividend rate for fair value assumption	0.00%	0.00%	0.00%
Expected volatility rate for fair value assumption, minimum	42.00%	59.00%	75.00%
Expected volatility rate for fair value assumption, maximum	54.00%	75.00%	81.00%
Weighted average volatility fair value assumption	53.00%	75.00%	80.00%
Risk free interest rate for fair value assumption, minimum	0.30%	0.30%	0.40%
Risk free interest rate for fair value assumption, maximum	0.70%	0.40%	1.40%
Expected term for fair value assumption	'	'	'4 years
Minimum [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Expected term for fair value assumption	'4 years	'4 years	'
Maximum [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Expected term for fair value assumption	'5 years	'6 years	'6 years

Share_Capital_Stock_Options_Ou

Share Capital Stock Options Outstanding (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Number of Outstanding Options	'	'
Balance, December 31, 2012 (in shares)	15,399,662	'
Granted (in shares)	2,121,375	'
Exercised (in shares)	-1,306,317	'
Forfeited (in shares)	-396,003	'
Expired (in shares)	-150,259	'
Balance, December 31, 2013 (in shares)	15,668,458	'
Exercisable, at December 31,2013 (in shares)	10,372,602	'
Vested, or expected to vest, at December 31, 2012 through the life of the options	15,142,311	'
Weighted Average Exercise Price $/Option	'	'
Weighted Average Exercise Price $/Option, beginning balance (in dollars per share)	5.11	'
Weighted Average Exercise Price $/Option, Granted (in dollars per share)	6.29	'
Weighted Average Exercise Price $/Options Exercised (in dollars per share)	-2.89	'
Weighted Average Exercise Price $/Options, Forfeited (in dollars per share)	-7.01	'
Weighted Average Exercise Price $/Options, Expired (in dollars per share)	-6.25	'
Weighted Average Exercise Price $/Option, ending balance (in dollars per share)	5.41	'
Weighted Average Exercise Price $/Option, Exercisable, at Decemeber 31, 2013 (in shares)	4.87	'
Weighted Average Exercise Price $/Option, Vested, or expected to vest, at December 31, 2012 through the life of the options	5.37	'
Restricted Stock Units (RSUs) [Member]	'	'
Number of Outstanding Share Units	'	'
Balance, December 31, 2012 (in shares)	922,045	0
Granted (in shares)	966,320	'
Exercised (in shares)	0	'
Forfeited (in shares)	-44,275	'
Expired (in shares)	0	'
Balance, December 31, 2013 (in shares)	922,045	0

Share_Capital_Allocation_of_Sh

Share Capital Allocation of Share Based Compensation (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Compensation cost	$11,354	$13,116	$13,723
Less: stock-based compensation costs capitalized	2,436	1,110	956
Total stock-based compensation expense	8,918	12,006	12,767
Employee Stock Option [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Compensation cost	'	'	13,723
Total stock-based compensation expense	8,418	13,116	'
Restricted Stock Units (RSUs) [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Compensation cost	$2,936	$0	$0

Share_Capital_Weighted_Average

Share Capital Weighted Average Shares (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'
Weighted average number of common and exchangeable shares outstanding	282,808,497	280,741,255	273,491,564
Shares issuable pursuant to warrants	0	175,061	2,708,183
Shares issuable pursuant to stock options	12,041,260	5,879,929	5,143,498
Shares assumed to be purchased from proceeds of stock options	-8,721,860	-2,623,991	-56,243
Weighted average number of diluted common and exchangeable shares outstanding	286,127,897	284,172,254	281,287,002

Share_Capital_Narrative_Detail

Share Capital Narrative (Details) (USD $)

12 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Jun. 27, 2012

Jun. 26, 2012

Mar. 18, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

31-May-13

Apr. 30, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

vote

General and Administrative Expense [Member]

General and Administrative Expense [Member]

General and Administrative Expense [Member]

Stock Options [Member]

Stock Options [Member]

Stock Options [Member]

Stock Options [Member]

Stock Options [Member]

Stock Options [Member]

Stock Options [Member]

Stock Options [Member]

Warrant [Member]

Warrant [Member]

Gran Tierra Exchangeco Inc [Member]

Gran Tierra Goldstrike Inc [Member]

Other Operating Expense [Member]

Other Operating Expense [Member]

Other Operating Expense [Member]

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

'

'

'

$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, issued

272,327,810

268,482,445

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Exchangeable shares outstanding (in shares)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6,348,313

4,534,127

Stock issued during period upon exercise of stock options (in shares)

1,306,317

482,841

1,695,049

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Exchange shares issued during period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,689,683

849,365

Votes per common stock

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common voting shares per exchangeable share (in shares)

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares available for issuance under 2007 Equity Incentive Plan

'

'

'

39,806,100

23,306,100

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Vesting period

'

'

'

'

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

'

'

Option term

'

'

'

'

'

'

'

'

'

'5 years

'10 years

'

'

'

'

'

'

'

'

'

'

Option term after leaving service of company

'

'

'

'

'

'

'

'

'

'3 months

'3 months

'

'

'

'

'

'

'

'

'

'

Stock option exercises in period (in shares)

-1,306,317

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash received from exercise of stock options

$3,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted average contractual term of of ouststanding stock options

'6 years 1 month 6 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted average contractual term of exercisable options

'5 years 9 months 18 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted Average Grant Date Fair Value $/Option, Granted in Period

'

'

'

'

'

'

'

'

'

'

'

$2.62

$3.33

$4.84

'

'

'

'

'

'

'

Weighted average grant date fair value for options vested (in dollars per share)

$3.94

$3.90

$2.26

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock Options [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total stock-based compensation expense

8,918,000

12,006,000

12,767,000

'

'

'

7,900,000

10,900,000

11,400,000

'

'

8,418,000

13,116,000

'

1,000,000

1,100,000

1,300,000

'

'

'

'

Unrecognized compensation cost related to unvested stock options

'

'

'

'

'

'

'

'

'

'

'

8,100,000

8,200,000

'

'

'

'

'

'

'

'

Unvested stock options recognition period

'2 years 10 months 24 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrants [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of warrants

12,400,000

10,200,000

6,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Intrinsic value of options outstanding

32,900,000

17,800,000

14,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Closing share price

$7.31

$5.51

$4.80

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Intrinsic value of options exercisable at period end

27,400,000

17,600,000

14,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Intrinsic value of options exercised during period at period end

3,300,000

1,400,000

6,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Intrinsic value of options outstanding, vested and expected to vest

$32,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted average remaining contractual term

'6 years 1 month 6 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrant outstanding (shares)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6,298,230

'

'

Number of securities purchaseable by warrants (in shares)

'

'

3,149,115

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrant exercise price (dollars per share)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.05

'

'

Warrants expiration date range start

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

20-Jun-12

'

'

Warrants expiration date range end

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30-Jun-12

'

'

Common shares issued-exercise of warrants (in shares)

'

2,766,834

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

735,817

'

'

Warrants exercised (in shares)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,550,668

1,471,634

'

'

Common shares issued-exercise of warrants, cashless exercise (in shares)

'

26,190

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common shares issued-exercise of warrants, shares withheld for cashless exchange (in shares)

'

7,143

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrants exercised, cashless exchange (in shares)

'

66,666

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrant expired unexercised (in shares)

'

680,896

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Earnings Per Share [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options excluded from the diluted income per share calculation

'

'

'

'

'

'

'

'

'

'

'

4,217,082

9,784,874

3,726,999

'

'

'

'

'

'

'

Asset_Retirement_Obligation_De

Asset Retirement Obligation (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]	'	'
Balance, beginning of year	$18,292,000	$12,669,000
Settlements	-2,068,000	-404,000
Liability incurred	2,623,000	5,190,000
Liability assumed in a business combination (Note 3)	0	410,000
Foreign exchange	-25,000	45,000
Accretion	1,279,000	998,000
Revisions in estimated liability	1,872,000	-616,000
Balance, end of year	21,973,000	18,292,000
Asset retirement obligation - current	518,000	28,000
Asset retirement obligation - long-term	21,455,000	18,264,000
Fair value of legally restricted assets	$1,900,000	$1,300,000

Income_Tax_Reconciliation_Deta

Income Tax Reconciliation (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income (loss) before income taxes	'	'	'
United States	($13,566)	($13,918)	$4,984
Foreign	275,402	211,281	229,263
INCOME BEFORE INCOME TAXES	261,836	197,363	234,247
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]	'	'	'
Effective income tax rate	35.00%	35.00%	35.00%
Income tax expense expected	91,643	69,077	81,986
Foreign currency translation adjustments	-2,978	5,473	-417
Impact of foreign taxes	-1,287	-1,833	3,890
Stock-based compensation	2,859	3,982	4,013
Increase in valuation allowance	39,028	6,709	36,815
Branch and other foreign loss pick-up	-2,362	-3,809	-14,363
Non-deductible third party royalty in Colombia	11,073	11,938	8,525
Non-taxable gain on acquisition	0	0	-7,595
Other permanent differences (1)	-2,428	6,167	-5,524
Total income tax expense	135,548	97,704	107,330
Current income tax expense	'	'	'
United States	1,250	1,233	1,029
Foreign	163,797	70,197	134,986
Total Current income tax expense	165,047	71,430	136,015
Deferred income tax expense (recovery)	'	'	'
United States	0	0	0
Foreign	-29,499	26,274	-28,685
Total Deferred income tax expense (recovery)	($29,499)	$26,274	($28,685)

Permanent_Differences_Reconcil

Permanent Differences Reconciliation (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Income Tax Disclosure [Abstract]	'	'
Tax benefit of operating loss carryforwards	$47,154	$51,920
Tax basis in excess of book basis	59,168	22,519
Foreign tax credits and other accruals	34,894	30,926
Tax benefit of capital loss carryforwards	4,769	4,779
Deferred tax assets before valuation allowance	145,985	110,144
Valuation allowance	-142,322	-106,226
Deferred tax assets, net	3,663	3,918
Deferred tax assets - current	2,256	2,517
Deferred tax assets - long-term	1,407	1,401
Deferred tax liabilities - current	-1,193	-337
Deferred tax liabilities - long-term	-177,082	-225,195
Deferred tax liabilities, net	-178,275	-225,532
Net Deferred Tax Liabilities	($174,612)	($221,614)

Unrecognized_Tax_Benefits_Deta

Unrecognized Tax Benefits (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]	'	'	'
Unrecognized tax benefit, beginning of year	$21,800	$20,500	$4,175
Increases for positions relating to prior year	3,200	1,300	585
Additions to tax position related to the current year	0	0	15,740
Decreases due to lapse of statute of limitations	-1,500	0	0
Settlements	-1,400	0	0
Unrecognized tax benefit, end of year	$22,100	$21,800	$20,500

Taxes_Narrative_Details

Taxes Narrative (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
	installment
Valuation Allowance [Line Items]	'	'	'	'	'
Effective income tax rate	'	35.00%	35.00%	35.00%	'
Income tax reconciliation, other adjustments	'	$9,100,000	$11,400,000	'	'
Income tax reconciliation, other adjustments offset by change in valuation allowance	'	3,800,000	8,700,000	'	'
Income tax reconciliation, other adjustments subject to local tax	'	2,900,000	2,700,000	'	'
Local income tax rate	'	1.75%	'	'	'
Operating loss carryforwards	'	215,400,000	213,100,000	'	'
Capital losses before valuation allowance	'	32,600,000	35,900,000	'	'
Net operating loss carryforward from foreign subsidiaries	'	213,800,000	215,200,000	'	'
Decrease in valuation allowance	'	-36,100,000	'	'	'
Unrecognized tax benefits	'	22,100,000	21,800,000	20,500,000	4,175,000
Unrecognized tax benefits that if recognized would impact the effective tax rate	'	12,600,000	'	'	'
Unrecognized income tax penalties and interest accrued	'	5,400,000	3,600,000	'	'
Other operating income (expense)	'	0	-9,336,000	0	'
Equity tax	'	0	0	8,271,000	'
Equity tax rate (in hundredths)	'	'	'	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	'	'	'	'
Unrecognized tax benefit included in income tax expense	'	1,800,000	2,000,000	600,000	'
Argentina [Member]	'	'	'	'	'
Valuation Allowance [Line Items]	'	'	'	'	'
Decrease in valuation allowance	'	($30,800,000)	'	'	'
Colombia [Member]	'	'	'	'	'
Valuation Allowance [Line Items]	'	'	'	'	'
Foreign income tax rate	'	34.00%	33.00%	33.00%	'
Effective Income Tax Rate Reconciliation, at Foreign Corporate Statutory Income Tax Rate, Percent	'	25.00%	33.00%	'	'
CREE tax rate	'	9.00%	'	'	'
CANADA	'	'	'	'	'
Valuation Allowance [Line Items]	'	'	'	'	'
Foreign income tax rate	'	'	25.00%	26.00%	'

Accounts_Payable_and_Accrued_L2

Accounts Payable and Accrued Liabilities (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Payables and Accruals [Abstract]	'	'
Trade	$97,947	$103,720
Royalties	14,969	17,607
VAT and withholding tax	24,882	28,169
Employee compensation	16,525	13,178
Other	7,644	6,007
Total	$161,967	$168,681

Commitments_and_Contingencies_1

Commitments and Contingencies Schedule of Contractual Obligations (Details) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Unrecorded Unconditional Purchase Obligation [Line Items]	'
Total	$183,594
2014	129,810
2015	27,373
2016	11,673
2017	3,838
2018	3,828
Thereafter	7,072
Oil transportation services [Member]	'
Unrecorded Unconditional Purchase Obligation [Line Items]	'
Total	52,339
2014	23,261
2015	10,635
2016	3,812
2017	3,812
2018	3,812
Thereafter	7,007
Drilling and G&G [Member]	'
Unrecorded Unconditional Purchase Obligation [Line Items]	'
Total	56,143
2014	55,806
2015	337
2016	0
2017	0
2018	0
Thereafter	0
Completions [Member]	'
Unrecorded Unconditional Purchase Obligation [Line Items]	'
Total	48,500
2014	26,544
2015	14,289
2016	7,667
2017	0
2018	0
Thereafter	0
Facility construction [Member]	'
Unrecorded Unconditional Purchase Obligation [Line Items]	'
Total	19,446
2014	18,748
2015	698
2016	0
2017	0
2018	0
Thereafter	0
Operating leases [Member]	'
Unrecorded Unconditional Purchase Obligation [Line Items]	'
Total	3,949
2014	2,690
2015	989
2016	163
2017	26
2018	16
Thereafter	65
Software and telecommunication [Member]	'
Unrecorded Unconditional Purchase Obligation [Line Items]	'
Total	1,992
2014	1,824
2015	137
2016	31
2017	0
2018	0
Thereafter	0
Consulting [Member]	'
Unrecorded Unconditional Purchase Obligation [Line Items]	'
Total	1,225
2014	937
2015	288
2016	0
2017	0
2018	0
Thereafter	$0

Commitments_and_Contingencies_2

Commitments and Contingencies (Details) (USD $)	12 Months Ended			3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
				Pending Litigation Escopetrol [Member]	Pending Litigation Escopetrol [Member]	Pending Litigation Moqueta Discovery [Member]	Pending Litigation Moqueta Discovery, Transportation and Related Costs [Member]
				bbl		bbl
Loss Contingencies [Line Items]	'	'	'	'	'	'	'
Rent expense	$3,100,000	$2,700,000	$3,000,000	'	'	'	'
Notes payable provided as security for letter of credit	52,500,000	34,200,000	'	'	'	'	'
Loss Contingency, Loss in Period, Barrels of Oil	'	'	'	44,025	'	'	'
Value of damages sought for loss contingency	$4,400,000	$0	'	'	$4,400,000	$38,400,000	$28,900,000
Threshold by which additional royalty due (barrels)	'	'	'	'	'	0	'
Total cumulative production of oil field (barrels)	'	'	'	'	'	2,300,000	'

Financial_Instruments_Fair_Val2

Financial Instruments, Fair Value Measurements and Credit Risk Contingent Consideration and Liability (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Fair Value Disclosures [Abstract]	'	'
Contingent consideration (Note 3)	$1,061	$1,061
Contingent liability (Note 11)	$4,400	$0

Financial_Instruments_Fair_Val3

Financial Instruments, Fair Value Measurements and Credit Risk (Details)

12 Months Ended

12 Months Ended

0 Months Ended

Dec. 31, 2013

Feb. 25, 2014

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Oct. 08, 2012

Jan. 20, 2012

Feb. 25, 2014

Feb. 25, 2014

USD ($)

Forward Contracts [Member]

Colombia [Member]

Colombia [Member]

Colombia [Member]

Colombia [Member]

Argentina [Member]

Brazil [Member]

Block-Brazil [Member]

Block-Brazil [Member]

Minimum [Member]

Maximum [Member]

Subsequent Event [Member]

customer

Geographic Concentration Risk [Member]

Geographic Concentration Risk [Member]

Geographic Concentration Risk [Member]

USD ($)

customer

Subsequent Event [Member]

Subsequent Event [Member]

COP

Sales Revenue, Segment [Member]

Sales Revenue, Segment [Member]

Sales Revenue, Segment [Member]

customer

COP

COP

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Participating interest percentage oil and gas property, remaining percentage

'

'

'

'

'

'

'

'

30.00%

30.00%

'

'

Number of significant customers

'

'

2

'

'

'

3

1

'

'

'

'

Concentration risk, percentage

'

'

'

86.00%

84.00%

91.00%

'

'

'

'

'

'

Foreign exchange losses, Colombian peso to U.S. dollar

$90,000

'

'

'

'

'

'

'

'

'

'

'

Amount of non-deliverable forward contract

'

149,800,000,000

'

'

'

'

'

'

'

'

'

'

Foreign Currency Exchange Rate, Remeasurement

'

'

'

'

'

'

'

'

'

'

2,034

2,053

Proceeds from argentinian subsidiary

'

'

'

'

'

'

11,100,000

'

'

'

'

'

Cash and cash equilvaents on deposit with local Argentinan banks

'

'

'

'

'

'

$19,500,000

'

'

'

'

'

Cash and cash equivalents on deposit with local Argentinan bank, percent

'

'

'

'

'

'

5.00%

'

'

'

'

'

Credit_Facilities_Details

Credit Facilities (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Oct. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
	Subsidiary	Foreign Line of Credit [Member]	Wells Fargo Bank, N.A. [Member]	Wells Fargo Bank, N.A. [Member]	Wells Fargo Bank, N.A. [Member]	Wells Fargo Bank, N.A. [Member]
			Revolving Credit Facility [Member]	Revolving Credit Facility [Member]	Revolving Credit Facility [Member]	Revolving Credit Facility [Member]
				Colombia [Member]	Minimum [Member]	Maximum [Member]
				Subsequent Event [Member]	LIBOR [Member]	LIBOR [Member]
				Foreign Line of Credit [Member]
Line of Credit Facility [Line Items]	'	'	'	'	'	'
Current borrowing capacity	'	'	$150,000,000	'	'	'
Maximum borrowing capacity	'	'	300,000,000	'	'	'
Number of subsidiaries used as collateral for reserve based facility	2	'	'	'	'	'
Basis spread on variable rate	'	'	'	'	2.25%	3.25%
Stand-by fee on unutilized balance	'	'	0.88%	'	'	'
Term of credit facility	'	'	'	'3 years	'	'
Max dividends payment allowable	'	$2,000,000	'	'	'	'

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
			Director - Brazil Drilling Program Related Party [Member]	Director - Peru drilling program related party [Member]
Related Party Transaction [Line Items]	'	'	'	'
Capitalization of drilling program	'	'	$11,900,000	$1,700,000
Accounts payable, drilling program	$72,400,000	$102,263,000	$2,000,000	$1,100,000