Gran Tierra Energy (GTE) 10-Q 6 Nov 14 2014 Q3 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	9 Months Ended
	Sep. 30, 2014	Oct. 31, 2014
Document and Entity Information [Abstract]	'	'
Entity Registrant Name	'GRAN TIERRA ENERGY INC.	'
Entity Central Index Key	'0001273441	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	276,059,008
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-14	'

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations and Retained Earnings (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
REVENUE AND OTHER INCOME	'	'	'	'
Oil and natural gas sales	$161,517	$170,825	$460,510	$507,315
Interest income	772	519	2,160	1,190
Total revenue and other income	162,289	171,344	462,670	508,505
EXPENSES	'	'	'	'
Operating	33,949	25,069	81,161	81,082
Depletion, depreciation, accretion and impairment	53,936	51,269	140,137	157,323
General and administrative	13,350	11,768	40,145	29,880
Foreign exchange (gain) loss	-12,438	430	-6,604	-18,549
Financial instruments loss (gain)	2,790	0	-2,223	0
Other loss	0	0	0	4,400
Total expenses	91,587	88,536	252,616	254,136
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	70,702	82,808	210,054	254,369
Income tax expense	-26,518	-42,595	-84,614	-104,572
INCOME FROM CONTINUING OPERATIONS	44,184	40,213	125,440	149,797
Loss from discontinued operations, net of income taxes (Note 3)	0	-7,156	-26,990	-11,044
NET INCOME AND COMPREHENSIVE INCOME	44,184	33,057	98,450	138,753
RETAINED EARNINGS, BEGINNING OF PERIOD	465,227	390,369	410,961	284,673
RETAINED EARNINGS, END OF PERIOD	$509,411	$423,426	$509,411	$423,426
Basic	'	'	'	'
INCOME FROM CONTINUING OPERATIONS	$0.15	$0.15	$0.44	$0.53
LOSS FROM DISCONTINUED OPERATIONS, NET OF INCOME TAXES	$0	($0.03)	($0.09)	($0.04)
NET INCOME PER SHARE — BASIC (in dollars per share)	$0.15	$0.12	$0.35	$0.49
Diluted	'	'	'	'
INCOME FROM CONTINUING OPERATIONS	$0.15	$0.15	$0.44	$0.53
LOSS FROM DISCONTINUED OPERATIONS, NET OF INCOME TAXES	$0	($0.03)	($0.09)	($0.04)
NET INCOME PER SHARE — DILUTED (in dollars per share)	$0.15	$0.12	$0.35	$0.49
WEIGHTED AVERAGE SHARES OUTSTANDING - BASIC (Note 6)	285,576,898	283,092,224	284,203,679	282,687,871
WEIGHTED AVERAGE SHARES OUTSTANDING - DILUTED (Note 6)	288,059,601	286,026,519	287,569,347	285,820,007

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current Assets	'	'
Cash and cash equivalents	$360,430	$428,800
Restricted cash	508	1,478
Accounts receivable	104,436	49,703
Marketable securities	11,711	0
Other financial instruments	414	0
Inventory	13,866	13,725
Taxes receivable	10,937	9,980
Prepaids	3,439	6,450
Deferred tax assets	1,099	2,256
Total Current Assets	506,840	512,392
Oil and Gas Properties (using the full cost method of accounting)	'	'
Proved	768,107	794,069
Unproved	516,657	456,001
Total Oil and Gas Properties	1,284,764	1,250,070
Other capital assets	9,519	10,102
Total Property, Plant and Equipment (Note 5)	1,294,283	1,260,172
Other Long-Term Assets	'	'
Restricted cash	2,392	2,300
Deferred tax assets	1,696	1,407
Taxes receivable	9,100	18,535
Other long-term assets	6,554	7,163
Goodwill	102,581	102,581
Total Other Long-Term Assets	122,323	131,986
Total Assets	1,923,446	1,904,550
Current Liabilities	'	'
Accounts payable	49,178	72,400
Accrued liabilities	89,882	89,567
Other financial instruments	652	0
Taxes payable	29,168	102,887
Deferred tax liabilities	1,461	1,193
Asset retirement obligation	7,353	518
Total Current Liabilities	177,694	266,565
Long-Term Liabilities	'	'
Deferred tax liabilities	168,495	177,082
Asset retirement obligation	19,565	21,455
Other long-term liabilities	12,333	9,540
Total Long-Term Liabilities	200,393	208,077
Contingencies	'	'
Shareholders’ Equity	'	'
Common Stock (Note 6) (276,018,597 and 272,327,810 shares of Common Stock and 10,221,506 and 10,882,440 exchangeable shares, par value $0.001 per share, issued and outstanding as at September 30, 2014, and December 31, 2013, respectively)	10,190	10,187
Additional paid in capital	1,025,758	1,008,760
Retained earnings	509,411	410,961
Total Shareholders’ Equity	1,545,359	1,429,908
Total Liabilities and Shareholders’ Equity	$1,923,446	$1,904,550

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]	'	'
Common shares, par value (in dollars per share)	$0.00	$0.00
Common shares, issued	276,018,597	272,327,810
Common shares, outstanding	276,018,597	272,327,810
Exchangeable shares, issued	10,221,506	10,882,440
Exchangeable shares, outstanding	10,221,506	10,882,440

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Operating Activities	'	'	'	'
Net income	$44,184	$33,057	$98,450	$138,753
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'	'
Loss from discontinued operations, net of income taxes	0	7,156	26,990	11,044
Depletion, depreciation, accretion and impairment	53,936	51,269	140,137	157,323
Foreign	'	'	1,431	-23,494
Non-cash stock-based compensation	'	'	4,341	5,505
Unrealized foreign exchange gain	'	'	-9,251	-16,850
Unrealized financial instruments loss	'	'	2,439	0
Equity tax	'	'	-3,283	-3,345
Cash settlement of asset retirement obligation	'	'	-211	-927
Other loss	0	0	0	4,400
Net change in assets and liabilities from operating activities of continuing operations	'	'	'	'
Accounts receivable and other long-term assets	'	'	-61,224	-35,574
Inventory	'	'	-1,688	12,592
Prepaids	'	'	2,565	-1,090
Accounts payable and accrued and other liabilities	'	'	-981	-8,332
Taxes receivable and payable	'	'	-55,084	80,932
Net cash provided by operating activities of continuing operations	'	'	144,631	320,937
Net cash (used in) provided by operating activities of discontinued operations	'	'	-4,792	28,150
Net cash provided by operating activities	'	'	139,839	349,087
Investing Activities	'	'	'	'
Decrease (increase) in restricted cash	'	'	877	-4,936
Additions to property, plant and equipment	'	'	-250,634	-249,606
Proceeds from sale of Argentina business unit, net of cash sold and transaction costs	'	'	42,755	0
Proceeds from sale of oil and gas properties	'	'	0	55,524
Net cash used in investing activities of continuing operations	'	'	-207,002	-199,018
Net cash used in investing activities of discontinued operations	'	'	-12,384	-13,104
Net cash used in investing activities	'	'	-219,386	-212,122
Financing Activities	'	'	'	'
Proceeds from issuance of shares of Common Stock	'	'	11,177	3,475
Net cash provided by financing activities	'	'	11,177	3,475
Net (decrease) increase in cash and cash equivalents	'	'	-68,370	140,440
Cash and cash equivalents, beginning of period	'	'	428,800	212,624
Cash and cash equivalents, end of period	360,430	353,064	360,430	353,064
Cash	229,018	296,520	229,018	296,520
Term deposits	131,412	56,544	131,412	56,544
Supplemental cash flow disclosures:	'	'	'	'
Cash paid for income taxes	'	'	118,540	38,978
Non-cash investing activities:	'	'	'	'
Net liabilities related to property, plant and equipment, end of period	$72,410	$65,645	$72,410	$65,645

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Shareholders' Equity (USD $)	Total	Share Capital [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]
In Thousands, unless otherwise specified
Balance, beginning of period at Dec. 31, 2012	'	$7,986	$998,772	$284,673
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'
Issue of shares of Common Stock	'	2,201	'	'
Exercise of stock options	'	'	1,570	'
Stock-based compensation	'	'	8,418	'
Net income	'	'	'	126,288
Balance, end of period at Dec. 31, 2013	1,429,908	10,187	1,008,760	410,961
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'
Issue of shares of Common Stock	'	3	'	'
Exercise of stock options	'	'	11,174	'
Stock-based compensation	'	'	5,824	'
Net income	98,450	'	'	98,450
Balance, end of period at Sep. 30, 2014	$1,545,359	$10,190	$1,025,758	$509,411

Description_of_Business

Description of Business	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Description of Business	'
	Description of Business
	Gran Tierra Energy Inc., a Nevada corporation (the “Company” or “Gran Tierra”), is a publicly traded oil and gas company engaged in the acquisition, exploration, development and production of oil and natural gas properties. The Company’s principal business activities are in Colombia, Peru and Brazil. Until June 25, 2014, the Company also had business activities in Argentina (Note 3).

Significant_Accounting_Policie

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Significant Accounting Policies	'
	Significant Accounting Policies
	These interim unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”). The information furnished herein reflects all normal recurring adjustments that are, in the opinion of management, necessary for the fair presentation of results for the interim periods.
	The note disclosure requirements of annual consolidated financial statements provide additional disclosures to that required for interim unaudited condensed consolidated financial statements. Accordingly, these interim unaudited condensed consolidated financial statements should be read in conjunction with the Company’s consolidated financial statements as at and for the year ended December 31, 2013, included in the Company’s 2013 Annual Report on Form 10-K, filed with the Securities and Exchange Commission (“SEC”) on February 26, 2014.
	The Company’s significant accounting policies are described in Note 2 of the consolidated financial statements which are included in the Company’s 2013 Annual Report on Form 10-K and are the same policies followed in these interim unaudited condensed consolidated financial statements, except as disclosed below. The Company has evaluated all subsequent events through to the date these interim unaudited condensed consolidated financial statements were issued.
	Discontinued Operations
	During the three months ended June 30, 2014, the Company completed the sale of its Argentina business unit and the discontinued operations criteria of Accounting Standards Codification ("ASC") 205-20, “Discontinued Operations” were met. Therefore, the results of the Company’s Argentina business unit are reflected separately as loss from discontinued operations, net of income taxes in the interim unaudited condensed consolidated statement of operations for the three and nine months ended September 30, 2014 and 2013, on a line immediately after “Income from continuing operations.” Additionally, cash flows of the Company’s Argentina business unit are reflected separately in the interim unaudited condensed consolidated statement of cash flows for the three and nine months ended September 30, 2014 and 2013 as cash provided by or used in operating and investing activities of discontinued operations. Amounts for 2013 have been reclassified to conform to the 2014 presentation. The reclassifications had no effect on net income. See Note 3, “Discontinued Operations,” for additional disclosure. The Company did not recognize depletion, depreciation and accretion expenses subsequent to May 29, 2014, the date the assets were classified as held for sale.
	Marketable Securities
	The Company acquired investments in marketable securities in connection with the sale of its Argentina business unit. Marketable securities were classified as trading securities, in accordance with ASC 320, “Investments – Debt and Equity Securities”, and are recorded in the consolidated balance sheet at fair value. The Company classifies trading securities as current or non-current based on the intent of management, the nature of the trading securities and whether they are readily available for use in current operations. Gains or losses on trading securities are recorded in the statement of operations as financial instruments gains or losses.
	Foreign Currency Derivatives
	The Company purchases Colombian peso non-deliverable forward contracts for purposes of fixing exchange rates at which it will purchase or sell Colombian pesos to settle its income tax installment payments. The Company does not intend to issue or hold derivative financial instruments for speculative trading purposes.
	The Company records derivative instruments on the balance sheet as either an asset or liability measured at fair value. The accounting for changes in the fair value of a derivative instrument depends on the intended use of the derivative and the resulting designation, which is established at the inception of a derivative. Generally because of the short-term nature of the contracts and their limited use, the Company does not apply hedge accounting, and changes in the fair value of those contracts are reflected in net income as financial instrument gains or losses in the interim unaudited condensed consolidated statement of operations. Cash settlements of the Company's derivative arrangements are classified as operating cash flows.
	The fair value of foreign currency derivatives is based on the estimated maturity value of the foreign exchange non-deliverable forward contracts, using applicable forward exchange rates. The most significant variable to the cash flow calculations is the estimation of forward foreign exchange rates. The resulting net future cash inflows or outflows at maturity of the contracts are the net value of the contract.
	Recently Adopted Accounting Pronouncements
	Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is fixed at the Reporting Date
	In February 2013, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2013- 04, “Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is fixed at the Reporting Date”. The ASU provides guidance for the recognition, measurement, and disclosure of obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date. Examples of obligations within the scope of this update include debt arrangements, other contractual obligations, and settled litigation and judicial rulings. The ASU was effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The implementation of this update did not materially impact the Company’s consolidated financial position, results of operations, cash flows or disclosure.
	Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists
	In July 2013, the FASB issued ASU 2013-11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists". The ASU provides guidance on the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The ASU was effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The implementation of this update did not materially impact the Company’s consolidated financial position, results of operations, cash flows, or disclosure.
	Recently Issued Accounting Pronouncements
	Revenue from Contracts with Customers
	In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers". The ASU creates a single source of revenue guidance for all companies in all industries and requires revenue recognition to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 sets forth a new revenue recognition model that requires identifying the contract, identifying the performance obligations, determining the transaction price, allocating the transaction price to performance obligations and recognizing the revenue upon satisfaction of performance obligations. The amendments in the ASU can be applied either retrospectively to each prior reporting period presented or retrospectively with the cumulative effect of initially applying the update recognized at the date of the initial application along with additional disclosures. The ASU will be effective for fiscal years, and interim periods within those years, beginning after December 15, 2016. The Company is currently assessing the impact the new standard will have on its consolidated financial position, results of operations, cash flows, and disclosure.

Discontinued_Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]	'
Discontinued Operations	'
	Discontinued Operations
	On June 25, 2014, the Company, through several of its indirect subsidiaries (the “Selling Subsidiaries”), sold its Argentina business unit to Madalena Energy Inc. ("Madalena") for aggregate consideration of $69.3 million, comprising $55.4 million in cash and $13.9 million in Madalena shares.
	The sale was made pursuant to agreements entered into by the Selling Subsidiaries (the “Agreements”); specifically, pursuant to the Agreements: (1) Madalena agreed to acquire from Gran Tierra Argentina Holdings ULC, an Alberta corporation (“GTE ULC”), and PCESA Petroleros Canadienses de Ecuador S.A., an Ecuador corporation (“PCESA”), both indirect subsidiaries of the Company, all of the outstanding shares of the Company’s indirect subsidiaries Gran Tierra Energy Argentina S.R.L. (“GTE Argentina”) and P.E.T.J.A. S.A, and agreed to acquire certain debt owed by GTE Argentina, for (a) approximately $44.8 million in cash, plus certain other adjustments and interest, and (b) shares of Madalena stock valued at $13.9 million; and (2) Madalena agreed to acquire from Gran Tierra Petroco Inc., an Alberta corporation (“Petroco”), an indirect subsidiary of the Company, all of the outstanding shares of the Company’s indirect subsidiary Petrolifera Petroleum Limited (“PPL”), and agreed to acquire certain debt owed by PPL , for approximately $10.6 million in cash, plus certain other adjustments and interest. Collectively, GTE Argentina, P.E.T.J.A. S.A., PPL and PPL’s subsidiaries held all of the assets of the Gran Tierra Energy Argentina business unit.
	Accordingly, the results of the Company’s Argentina business unit are classified as “Loss from discontinued operations, net of income taxes” on the consolidated statements of operations for the three and nine months ended September 30, 2014, and 2013. Additionally, cash flows of the Company’s Argentina business unit are reflected separately in the interim unaudited condensed consolidated statement of cash flows for the three and nine months ended September 30, 2014 and 2013 as cash provided by or used in operating and investing activities of discontinued operations. Amounts for 2013 have been reclassified to conform to the 2014 presentation. The reclassifications had no effect on net income.
	Revenue and other income and loss from discontinued operations for the three and nine months ended September 30, 2014, and 2013, were as follows:
			Three Months Ended September 30,					Nine Months Ended September 30,
	(Thousands of U.S. Dollars)		2014		2013			2014			2013
	Revenue and other income		$	—	$	18,316		$	31,985		$	55,335
	Loss from operations of discontinued operations before income taxes		$	—	$	(4,163	)	$	(6,252	)	$	(6,253	)
	Income tax expense		—		(2,993		)	(1,458		)	(4,791		)
	Loss from operations of discontinued operations		—		(7,156		)	(7,710		)	(11,044		)
	Loss on sale before income taxes		—		—			(18,235		)	—
	Income tax expense		—		—			(1,045		)	—
	Loss on sale		—		—			(19,280		)	—
	Loss from discontinued operations, net of income taxes		$	—	$	(7,156	)	$	(26,990	)	$	(11,044	)
	The Company classified the Argentina business unit as held for sale at May 29, 2014. The Company did not meet the criteria to classify the Argentina business unit as held for sale at March 31, 2014, or prior periods. The cost center ceiling with respect to the Company’s Argentina full cost pool exceeded the net capitalized cost of the cost center at March 31, 2014, and as such, no ceiling test writedown was required. 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.
	At December 31, 2013, assets and liabilities related to discontinued operations were as follows:
		As at
	(Thousands of U.S. Dollars)	December 31, 2013
	Current assets (1)	$	39,125
	Property, plant and equipment	94,446
	Other long-term assets	1,839
		$	135,410
	Current liabilities	$	37,612
	Long-term liabilities	9,755
		$	47,367
	(1) Included cash of $21.2 million.

Segment_and_Geographic_Reporti

Segment and Geographic Reporting	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
Segment and Geographic Reporting	'
	Segment and Geographic Reporting
	The Company is primarily engaged in the exploration and production of oil and natural gas. The Company’s reportable segments are Colombia, Peru and Brazil based on geographic organization. Prior to classifying the Company’s Argentina business unit as discontinued operations (Note 3), Argentina was a reportable segment. The All Other category represents the Company’s corporate activities. The amounts disclosed in the tables below exclude the results of the Argentina business unit unless otherwise noted. Certain subsidiaries which were previously included in the All Other category were sold as part of the Argentina business unit, and therefore amounts disclosed in the All Other category have been reclassified to exclude amounts reported in loss from discontinued operations. The Company evaluates reportable segment performance based on income or loss from continuing operations before income taxes.
	The following tables present information on the Company’s reportable segments and other activities:
		Three Months Ended September 30, 2014
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	153,815	$	—		$	7,702		$	—		$	161,517
	Interest income	98		1			433			240			772
	Depletion, depreciation, accretion and impairment	51,144		109			2,429			254			53,936
	Depletion, depreciation, accretion and impairment - per unit of production	28.31		—			26.3			—			28.4
	Income (loss) from continuing operations before income taxes	81,258		(3,345		)	1,746			(8,957		)	70,702
	Segment capital expenditures	50,785		40,730			3,377			527			95,419
		Three Months Ended September 30, 2013
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	164,241	$	—		$	6,584		$	—		$	170,825
	Interest income	111		1			281			126			519
	Depletion, depreciation, accretion and impairment	46,821		73			4,129			246			51,269
	Depletion, depreciation, accretion and impairment - per unit of production	27.48		—			59.72			—			28.92
	Income (loss) from continuing operations before income taxes	89,215		(1,404		)	(337		)	(4,666		)	82,808
	Segment capital expenditures (1)	39,608		11,063			(22,500		)	289			28,460
		Nine Months Ended September 30, 2014
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	438,100	$	—		$	22,410		$	—		$	460,510
	Interest income	419		1			1,292			448			2,160
	Depletion, depreciation, accretion and impairment	131,742		420			7,249			726			140,137
	Depletion, depreciation, accretion and impairment - per unit of production	26.7		—			29.24			—			27.05
	Income (loss) from continuing operations before income taxes	229,750		(7,811		)	7,446			(19,331		)	210,054
	Segment capital expenditures	147,016		103,535			17,176			1,132			268,859
		Nine Months Ended September 30, 2013
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	488,577	$	—		$	18,738		$	—		$	507,315
	Interest income	415		27			292			456			1,190
	Depletion, depreciation, accretion and impairment	141,141		272			15,143			767			157,323
	Depletion, depreciation, accretion and impairment - per unit of production	27.58		—			75.74			—			29.59
	Income (loss) from continuing operations before income taxes	275,353		(4,984		)	(3,663		)	(12,337		)	254,369
	Segment capital expenditures (1)	118,758		59,911			12,021			528			191,218
	(1) In the third quarter of 2013, segment capital expenditures were net of proceeds of $54.0 million relating to termination of a farm-in agreement in Brazil. Additionally, segment capital expenditures for the nine months ended September 30, 2013, were net of proceeds of $1.5 million relating to the Company's sale of its 15% working interest in the Mecaya Block in Colombia (Note 5).
		As at September 30, 2014
	(Thousands of U.S. Dollars)	Colombia		Peru			Brazil			All Other			Total Excluding Discontinued Operations		Discontinued Operations		Total
	Property, plant and equipment	$	865,331	$	281,646		$	143,938		$	3,368		$	1,294,283	$	—	$	1,294,283
	Goodwill	102,581		—			—			—			102,581		—		102,581
	All other assets	264,064		31,439			19,989			211,090			526,582		—		526,582
	Total Assets	$	1,231,976	$	313,085		$	163,927		$	214,458		$	1,923,446	$	—	$	1,923,446
		As at December 31, 2013
	(Thousands of U.S. Dollars)	Colombia		Peru			Brazil			All Other			Total Excluding Discontinued Operations		Discontinued Operations		Total
	Property, plant and equipment	$	850,359	$	178,531		$	133,874		$	2,962		$	1,165,726	$	94,446	$	1,260,172
	Goodwill	102,581		—			—			—			102,581		—		102,581
	All other assets	233,336		24,240			24,477			218,780			500,833		40,964		541,797
	Total Assets	$	1,186,276	$	202,771		$	158,351		$	221,742		$	1,769,140	$	135,410	$	1,904,550
	The Company’s revenues are derived principally from uncollateralized sales to customers in the oil and natural gas industry. The concentration of credit risk in a single industry affects the Company’s overall exposure to credit risk because customers may be similarly affected by changes in economic and other conditions.
	In the three months ended September 30, 2014, the Company had three significant customers in Colombia: Ecopetrol S.A. ("Ecopetrol"), Hocol Petroleum Limited ("Hocol") and one other customer, which accounted for 37%, 11% and 38%, respectively, of the Company's consolidated oil and natural gas sales from continuing operations. For the three months ended September 30, 2013, sales to Ecopetrol and the other customer accounted for 61% and 31%, respectively, of the Company's consolidated oil and natural gas sales from continuing operations. In the nine months ended September 30, 2014 and 2013, sales to Ecopetrol accounted for 46% and 57%, respectively, and sales to the other customer accounted for 38% and 32%, respectively, of the Company's consolidated oil and natural gas sales from continuing operations. Sales to Hocol were not significant in the nine months ended September 30, 2014, or in the three and nine months ended September 30, 2013.

Property_Plant_and_Equipment_a

Property, Plant and Equipment and Inventory	9 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment and Inventory	'
	Property, Plant and Equipment and Inventory
	Property, Plant and Equipment
		As at September 30, 2014							As at December 31, 2013
	(Thousands of U.S. Dollars)	Cost		Accumulated			Net book value		Cost		Accumulated			Net book value
				depletion,							depletion,
				depreciation							depreciation
				and							and
				impairment							impairment
	Oil and natural gas properties
	Proved	$	1,927,314	$	(1,159,207	)	$	768,107	$	1,799,544	$	(1,005,475	)	$	794,069
	Unproved	516,657		—			516,657		456,001		—			456,001
		2,443,971		(1,159,207		)	1,284,764		2,255,545		(1,005,475		)	1,250,070
	Furniture and fixtures and leasehold improvements	9,202		(7,028		)	2,174		8,919		(6,568		)	2,351
	Computer equipment	13,732		(6,820		)	6,912		14,786		(7,605		)	7,181
	Automobiles	802		(369		)	433		1,381		(811		)	570
	Total Property, Plant and Equipment	$	2,467,707	$	(1,173,424	)	$	1,294,283	$	2,280,631	$	(1,020,459	)	$	1,260,172
	Depletion and depreciation expense from continuing operations on property, plant and equipment for the three months ended September 30, 2014, was $49.9 million (three months ended September 30, 2013 - $51.5 million) and for the nine months ended September 30, 2014, was $140.4 million (nine months ended September 30, 2013 - $150.3 million). A portion of depletion and depreciation expense was recorded as inventory in each period and adjusted for inventory changes. In the second quarter of 2013, the Company recorded 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.
	On August 6, 2014, the Company announced proved reserves, net after royalty and calculated in accordance with SEC rules as of May 31, 2014, for the Tiê field, in Brazil increased after production for the five months ended May 31, 2014, to 3.0 MMBOE from 1.7 MMBOE, proved and probable reserves increased to 4.9 MMBOE from 3.3 MMBOE and proved, probable and possible reserves increased to 7.2 MMBOE from 5.0 MMBOE. The reserve revisions were due to new production from the Agua Grande formation, results of seismic reprocessing, and additional reservoir volume in the Sergi formation.
	In the second quarter of 2013, the Company received proceeds of $1.5 million relating to a sale of its 15% working interest in the Mecaya Block in Colombia.
	During 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.
	During the third quarter of 2014, the Agência Nacional de Petróleo, Gás Natural e Biocombustíveis ("ANP") in Brazil granted the Company extensions or suspensions of the first exploration phase of the concession agreements on Blocks REC-T-129, REC-T-142 and REC-T-155 to May 24, 2015. 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 an application to the ANP for a suspension of the exploration phase of this block. The Company has not yet received a decision from the ANP regarding this suspension application. At September 30, 2014, unproved properties included $3.6 million relating to exploration expenditures on this block. Management assessed this block for impairment at September 30, 2014, and concluded no impairment had occurred.
	Unproved oil and natural gas properties consist of exploration lands held in Colombia, Peru and Brazil. As at September 30, 2014, the Company had $170.2 million (December 31, 2013 - $176.1 million) of unproved assets in Colombia, $280.4 million (December 31, 2013 - $177.5 million) of unproved assets in Peru, and $66.1 million (December 31, 2013 - $84.2 million) of unproved assets in Brazil for a total of $516.7 million (December 31, 2013 - $437.8 million). At December 31, 2013, the Company had $18.2 million of unproved assets in Argentina, which were sold as part of the sale of the Argentina business unit on June 25, 2014. Unproved oil and natural gas properties are being held for their exploration value and are not being depleted pending determination of the existence of proved reserves. Gran Tierra will continue to assess the unproved properties over the next several years as proved reserves are established and as exploration warrants whether or not future areas will be developed.
	Inventory
	At September 30, 2014, oil and supplies inventories were $11.5 million and $2.4 million, respectively (December 31, 2013 - $11.7 million and $2.0 million, respectively).

Share_Capital

Share Capital	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Share Capital	'
	Share Capital
	The Company’s authorized share capital consists of 595,000,002 shares of capital stock, of which 570 million are designated as Common Stock, par value $0.001 per share, 25 million are designated as Preferred Stock, par value $0.001 per share, and two shares are designated as special voting stock, par value $0.001 per share.
	As at September 30, 2014, outstanding share capital consists of 276,018,597 shares of Common Stock of the Company, 5,687,379 exchangeable shares of Gran Tierra Exchangeco Inc., (the "Exchangeco exchangeable shares") and 4,534,127 exchangeable shares of Gran Tierra Goldstrike Inc. (the "Goldstrike exchangeable shares"). The redemption date for the Exchangeco exchangeable shares and the Goldstrike exchangeable shares is a date to be established by the applicable Board of Directors. During the nine months ended September 30, 2014, 3,029,853 shares of Common Stock were issued upon the exercise of stock options and 660,934 shares of Common Stock were issued upon the exchange of the Exchangeco exchangeable shares.
	The holders of shares of Common Stock are entitled to one vote for each share on all matters submitted to a stockholder vote and are entitled to share in all dividends that the Company’s Board of Directors, in its discretion, declares from legally available funds. The holders of Common Stock have no pre-emptive rights, no conversion rights, and there are no redemption provisions applicable to the shares. Holders of exchangeable shares have substantially the same rights as holders of shares of Common Stock. Each exchangeable share is exchangeable into one share of Common Stock of the Company.
	Restricted Stock Units and Stock Options
	The Company grants time-vested restricted stock units ("RSUs") to certain officers, employees and consultants. Additionally, the Company grants options to purchase shares of Common Stock to certain directors, officers, employees and consultants. The following table provides information about RSU and stock option activity for the nine months ended September 30, 2014:
		RSUs			Options
		Number of Outstanding Share Units			Number of Outstanding Options			Weighted Average Exercise Price $/Option
	Balance, December 31, 2013	922,045			15,668,458			5.41
	Granted	903,205			2,407,730			7.06
	Exercised	(415,538	)		(3,029,853	)		(3.68	)
	Forfeited	(50,980	)		(197,676	)		(6.59	)
	Expired	—			(720,724	)		(7.12	)
	Balance, September 30, 2014	1,358,732			14,127,935			5.96
	For the nine months ended September 30, 2014, 3,029,853 shares of Common Stock were issued for cash proceeds of $11.2 million upon the exercise of stock options (nine months ended September 30, 2013 - $3.5 million).
	The weighted average grant date fair value for options granted in the three months ended September 30, 2014, was $2.21 (three months ended September 30, 2013 - $2.34) and for the nine months ended September 30, 2014, was $2.50 (nine months ended September 30, 2013 - $2.62).
	The amounts recognized for stock-based compensation were as follows:
	(Thousands of U.S. Dollars)		Three Months Ended September 30,								Nine Months Ended September 30,
			2014				2013				2014			2013
	Compensation costs for stock options		$	1,961			$	2,133			$	5,824		$	6,314
	Compensation costs for RSUs		326				1,282				3,967			1,901
			2,287				3,415				9,791			8,215
	Less: Stock-based compensation costs capitalized		(278		)		(1,718		)		(2,100		)	(2,102		)
	Stock-based compensation costs expensed		$	2,009			$	1,697			$	7,691		$	6,113
	Of the total compensation expense for the three months ended September 30, 2014, $2.0 million (three months ended September 30, 2013 - $1.3 million) was recorded in G&A expenses, $nil (three months ended September 30, 2013 – $0.1 million) was recorded in operating expenses and $nil (three months ended September 30, 2013 – $0.3 million ) was recorded in loss from discontinued operations. Of the total compensation expense for the nine months ended September 30, 2014, $6.1 million (nine months ended September 30, 2013 – $5.1 million) was recorded in G&A expenses, $0.3 million (nine months ended September 30, 2013 – $0.4 million) was recorded in operating expenses and $1.3 million (nine months ended September 30, 2013 - $0.6 million) was recorded in loss from discontinued operations.
	At September 30, 2014, there was $8.6 million (December 31, 2013 - $8.1 million) of unrecognized compensation cost related to unvested stock options and RSUs which is expected to be recognized over a weighted average period of 2.9 years. The vesting of certain RSUs and stock options was accelerated as a result of the sale of the Argentina business unit and the retirement of our former Chief Operating Officer.
	Income per share
	Basic 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 income per share is calculated by adjusting the weighted average number of shares of Common Stock and exchangeable shares outstanding for the dilutive effect, if any, of share equivalents. The Company uses the treasury stock method to determine the dilutive effect. This method assumes that all Common Stock equivalents have been exercised at the beginning of the period (or at the time of issuance, if later), and that the funds obtained thereby were used to purchase shares of Common Stock of the Company at the volume weighted average trading price of shares of Common Stock during the period.
			Three Months Ended September 30,						Nine Months Ended September 30,
			2014			2013			2014			2013
	Weighted average number of common and exchangeable shares outstanding		285,576,898			283,092,224			284,203,679			282,687,871
	Weighted average shares issuable pursuant to stock options		8,117,355			12,428,489			9,399,930			10,823,968
	Weighted average shares assumed to be purchased from proceeds of stock options		(5,634,652	)		(9,494,194	)		(6,034,262	)		(7,691,832	)
	Weighted average number of diluted common and exchangeable shares outstanding		288,059,601			286,026,519			287,569,347			285,820,007
	For the three months ended September 30, 2014, 6,884,227 options (three months ended September 30, 2013 - 3,472,472 options) were excluded from the diluted income per share calculation as the options were anti-dilutive. For the nine months ended September 30, 2014, 6,925,117 options (nine months ended September 30, 2013 - 5,584,732 options) were excluded from the diluted income per share calculation as the options were anti-dilutive.

Asset_Retirement_Obligation

Asset Retirement Obligation	9 Months Ended
	Sep. 30, 2014
Asset Retirement Obligation [Abstract]	'
Asset Retirement Obligation	'
	Asset Retirement Obligation
	Changes in the carrying amounts of the asset retirement obligation associated with the Company’s oil and natural gas properties were as follows:
		Nine Months Ended			Year Ended
	(Thousands of U.S. Dollars)	September 30, 2014			December 31, 2013
	Balance, beginning of period	$	21,973		$	18,292
	Settlements	(211		)	(2,068		)
	Liability incurred	10,262			2,623
	Liabilities associated with the Argentina business unit sold (Note 3)	(10,170		)	—
	Foreign exchange	(14		)	(25		)
	Accretion	1,022			1,279
	Revisions in estimated liability	4,056			1,872
	Balance, end of period	$	26,918		$	21,973
	Asset retirement obligation - current	$	7,353		$	518
	Asset retirement obligation - long-term	19,565			21,455
	Balance, end of period	$	26,918		$	21,973
	Revisions to estimated liabilities relate primarily to changes in estimates of asset retirement costs and include, but are not limited to, revisions of estimated inflation rates, changes in property lives and the expected timing of settling the asset retirement obligation. At September 30, 2014, the fair value of assets that are legally restricted for purposes of settling the asset retirement obligation was $2.4 million (December 31, 2013 - $1.9 million). These assets are included in restricted cash on the Company's interim unaudited condensed consolidated balance sheet.

Taxes

Taxes	9 Months Ended
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
Taxes	'
	Taxes
	The income tax expense reported differs from the amount computed by applying the U.S. statutory rate to income from continuing operations before income taxes for the following reasons:
		Nine Months Ended September 30,
	(Thousands of U.S. Dollars)	2014			2013
	Income (loss) from continuing operations before income taxes
	United States	$	(16,450	)	$	(8,488	)
	Foreign	226,504			262,857
		210,054			254,369
		35		%	35		%
	Income tax expense from continuing operations expected	73,519			89,029
	Foreign currency translation adjustments	(1,464		)	(7,263		)
	Impact of foreign taxes	(3,361		)	(3,388		)
	Other local taxes	3,192			1,497
	Stock-based compensation	2,155			1,887
	Increase in valuation allowance	2,146			17,975
	Non-deductible third party royalty in Colombia	7,554			8,812
	Other permanent differences	873			(3,977		)
	Total income tax expense from continuing operations	$	84,614		$	104,572
	Current income tax expense from continuing operations
	United States	$	990		$	813
	Foreign	82,193			127,253
		83,183			128,066
	Deferred income tax expense (recovery) from continuing operations
	Foreign	1,431			(23,494		)
	Total income tax expense from continuing operations	$	84,614		$	104,572
		As at
	(Thousands of U.S. Dollars)	September 30, 2014			31-Dec-13
	Deferred Tax Assets
	Tax benefit of operating loss carryforwards	$	36,367		$	47,154
	Tax basis in excess of book basis	40,257			59,168
	Foreign tax credits and other accruals	19,917			34,894
	Tax benefit of capital loss carryforwards	29,114			4,769
	Deferred tax assets before valuation allowance	125,655			145,985
	Valuation allowance	(122,860		)	(142,322		)
		$	2,795		$	3,663
	Deferred tax assets - current	$	1,099		$	2,256
	Deferred tax assets - long-term	1,696			1,407
		2,795			3,663
	Deferred tax liabilities - current	(1,461		)	(1,193		)
	Deferred tax liabilities - long-term	(168,495		)	(177,082		)
		(169,956		)	(178,275		)
	Net Deferred Tax Liabilities	$	(167,161	)	$	(174,612	)
	As at September 30, 2014, the Company had operating loss carryforwards of $122.7 million (December 31, 2013 - $215.4 million) and capital loss carryforwards of $227.0 million (December 31, 2013 – $32.6 million) before valuation allowance. Of these operating loss carryforwards and capital loss carryforwards, $308.8 million (December 31, 2013 - $213.8 million) were losses generated by the foreign subsidiaries of the Company. In certain jurisdictions, the operating loss carryforwards expire between 2014 and 2034 and the capital loss carryforwards expire between 2016 and 2017, while certain other jurisdictions allow operating and capital losses to be carried forward indefinitely.
	As at September 30, 2014, the total amount of Gran Tierra’s unrecognized tax benefit related to continuing operations was $4.1 million (December 31, 2013 - $2.9 million), which if recognized would affect the Company’s effective tax rate. To the extent interest and penalties may be assessed by taxing authorities on any underpayment of income tax, such amounts have been accrued and are classified as a component of income taxes in the consolidated statement of operations.
	Changes in the Company's unrecognized tax benefit relating to continuing operations are as follows:
		Nine Months Ended September 30,
		2014			2013
	(Thousands of U.S. Dollars)
	Unrecognized tax benefit relating to continuing operations at beginning of period	$	2,900		$	5,900
	Increases for positions relating to prior year	1,200			—
	Decreases for positions relating to prior year	—			(3,200		)
	Unrecognized tax benefit relating to continuing operations at end of period	$	4,100		$	2,700
	The Company and its subsidiaries file income tax returns in U.S. federal and state jurisdictions and certain other foreign jurisdictions. The Company is potentially subject to income tax examinations for the tax years 2006 through 2013 in certain jurisdictions. The Company does not anticipate any material changes to the unrecognized tax benefit disclosed above within the next twelve months.
	At September 30, 2014, and December 31, 2013, accounts payable included the remaining unpaid balance of equity tax liability of $nil (December 31, 2013 - $3.3 million), a Colombian tax of 6% on a legislated measure calculated based on the Company’s Colombian segment’s balance sheet equity for tax purposes at January 1, 2011. The tax is payable in eight semi-annual installments over four years, but was expensed in the first quarter of 2011 at the commencement of the four-year period.

Contingencies

Contingencies	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Contingencies	'
	Contingencies
	Gran Tierra Energy Colombia, Ltd. and Petrolifera Petroleum (Colombia) Ltd (collectively “GTEC”) and Ecopetrol, the contracting parties of the Guayuyaco Association Contract, are engaged in a dispute regarding the interpretation of the procedure for allocation of oil produced and sold during the long-term test of the Guayuyaco-1 and Guayuyaco-2 wells, prior to GTEC's purchase of the companies originally involved in the dispute. There was no agreement between the parties, and Ecopetrol filed a lawsuit in the Contravention Administrative Tribunal in the District of Cauca (the "Tribunal") regarding this matter. During the first quarter of 2013, the Tribunal ruled in favor of Ecopetrol and awarded Ecopetrol 44,025 bbl of oil. GTEC has filed an appeal of the ruling to the Supreme Administrative Court (Consejo de Estado) in a second instance procedure. During the three months ended March 31, 2013, based on market oil prices in Colombia, Gran Tierra accrued $4.4 million in the interim unaudited condensed consolidated financial statements in relation to this dispute (Note 10).
	Gran Tierra’s production from the Costayaco Exploitation Area is subject to an additional royalty (the "HPR royalty"), which applies when cumulative gross production from an Exploitation Area is greater than five MMbbl. The HPR royalty is calculated on the difference between a trigger price defined in the Chaza Block exploration and production contract (the "Chaza Contract") and the sales price. The Agencia Nacional de Hidrocarburos (National Hydrocarbons Agency) (“ANH”) has interpreted the Chaza Contract as requiring that the HPR royalty must be paid with respect to all production from the Moqueta Exploitation Area and initiated a noncompliance procedure under the Chaza Contract, which was contested by Gran Tierra because the Moqueta Exploitation Area and the Costayaco Exploitation Area are separate Exploitation Areas. ANH did not proceed with that noncompliance procedure. Gran Tierra also believes that the evidence shows that the Costayaco and Moqueta fields are two clearly separate and independent hydrocarbon accumulations. Therefore, it is Gran Tierra’s view that, pursuant to the terms of the Chaza Contract, the HPR royalty is only to be paid with respect to production from the Moqueta Exploitation Area when the accumulated oil production from that Exploitation Area exceeds five MMbbl. Discussions with the ANH have not resolved this issue and Gran Tierra has initiated the dispute resolution process under the Chaza Contract and filed an arbitration claim seeking a decision that the HPR royalty is not payable until production from the Moqueta Exploitation Area exceeds five MMbbl. The ANH filed a response to the claim seeking a declaration that its interpretation is correct and a counterclaim seeking, amongst other remedies, declarations that Gran Tierra breached the Chaza Contract by not paying the disputed HPR royalty, that the amount of the alleged HPR royalty that is payable, and that the Chaza Contract be terminated. Gran Tierra filed a response to the ANH's counterclaim and filed its comments on the ANH's responses to Gran Tierra's claim. The ANH filed an amended counterclaim and Gran Tierra filed a response to the ANH's amended counterclaim. As at September 30, 2014, total cumulative production from the Moqueta Exploitation Area was 3.7 MMbbl. The estimated compensation which would be payable on cumulative production to that date if the ANH is successful in the arbitration is $59.7 million. At this time no amount has been accrued in the interim unaudited condensed consolidated financial statements nor deducted from the Company's reserves for the disputed HPR royalty as Gran Tierra does not consider it probable that a loss will be incurred.
	Additionally, the ANH and Gran Tierra are engaged in discussions regarding the interpretation of whether certain transportation and related costs are eligible to be deducted in the calculation of the HPR royalty. Discussions with the ANH are ongoing. Based on the Company's understanding of the ANH's position, the estimated compensation which would be payable if the ANH’s interpretation is correct could be up to $38.9 million as at September 30, 2014. At this time no amount has been accrued in the financial statements as Gran Tierra does not consider it probable that a loss will be incurred.
	The Company provided the purchaser of its Argentina business unit with certain indemnifications. The Company remains responsible for certain contingent liabilities related to such indemnifications, subject to defined limitations. The Company does not believe that these obligations are probable of having a material impact on its consolidated financial position, results of operations or cash flows.
	In addition to the above, Gran Tierra has several other lawsuits and claims pending. Although the outcome of these other lawsuits and disputes cannot be predicted with certainty, Gran Tierra believes the resolution of these matters would not have a material adverse effect on the Company’s consolidated financial position, results of operations or cash flows. Gran Tierra records costs as they are incurred or become probable and determinable.
	Letters of credit
	At September 30, 2014, the Company had provided promissory notes totaling $73.6 million (December 31, 2013 - $52.5 million) as security for letters of credit relating to work commitment guarantees contained in exploration contracts and other capital or operating requirements.

Financial_Instruments_Fair_Val

Financial Instruments, Fair Value Measurements and Credit Risk	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Financial Instruments, Fair Value Measurements and Credit Risk	'
	Financial Instruments, Fair Value Measurement, Credit Risk and Foreign Exchange Risk
	Financial Instruments
	At September 30, 2014, the Company’s financial instruments recognized in the balance sheet consist of cash and cash equivalents, restricted cash, accounts receivable, trading securities, accounts payable, accrued liabilities, foreign currency derivatives included in current assets and liabilities and contingent consideration and contingent liability included in other long-term liabilities.
	Fair Value Measurement
	The fair value of the trading securities, foreign currency derivatives, contingent consideration and contingent liability are being remeasured at the estimated fair value at each reporting period.
	The fair value of the trading securities which were received as consideration on the sale of the Company's Argentina business unit (Note 3) was estimated based on quoted market prices in an active market.
	The fair value of foreign currency derivatives was based on the estimated maturity value of foreign exchange non-deliverable forward contracts using applicable forward exchange rates. The most significant variable to the cash flow calculations is the estimation of forward foreign exchange rates. The resulting future cash inflows or outflows at maturity of the contracts are the net value of the contract.
	The fair value of the contingent consideration, which relates to the acquisition of the remaining 30% working interest in certain properties in Brazil, was estimated 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 is determined in accordance with accepted valuation methods.
	The fair value of the contingent liability which relates to a dispute with Ecopetrol (Note 9) was estimated based on the fair value of the amount awarded using market oil prices in Colombia.
	The fair value of the trading securities, foreign currency derivative assets and liabilities, contingent consideration and the contingent liability related to the Ecopetrol dispute at September 30, 2014, and December 31, 2013, were as follows:
			As at
	(Thousands of U.S. Dollars)		September 30, 2014			December 31, 2013
	Trading securities (Note 3)		$	11,711		$	—
	Foreign currency derivative asset		414			—
			$	12,125		—
	Foreign currency derivative liability		$	652		$	—
	Contingent consideration liability		1,061			1,061
	Contingent liability (Note 9)		4,400			4,400
			$	6,113		$	5,461
	The following table presents gains or losses on financial instruments recognized in the accompanying interim unaudited condensed consolidated statements of operations:
	(Thousands of U.S. Dollars)	Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
	Trading securities loss	$	2,540		$	—		$	2,201		$	—
	Foreign currency derivatives loss (gain)	250			—			(4,424		)	—
		$	2,790		$	—		$	(2,223	)	$	—
	These losses and gains are presented as financial instruments loss or gain in the interim unaudited condensed consolidated statements of operations and cash flows.
	The fair value of long-term restricted cash approximates its carrying value because interest rates are variable and reflective of market rates. The fair values of other financial instruments approximate their carrying amounts due to the short-term maturity of these instruments.
	GAAP establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. This hierarchy consists of three broad levels. Level 1 inputs consist of quoted prices (unadjusted) in active markets for identical assets and liabilities and have the highest priority. Level 2 and 3 inputs are based on significant other observable inputs and significant unobservable inputs, respectively, and have lower priorities. The Company uses appropriate valuation techniques based on the available inputs to measure the fair values of assets and liabilities.
	At September 30, 2014, the fair value of the trading securities acquired in connection with the disposal of the Argentina business unit (Note 3) was determined using Level 1 inputs. At September 30, 2014, the fair value of the foreign currency derivatives was determined using Level 2 inputs. At September 30, 2014, and December 31, 2013, the fair value of the contingent consideration payable in connection with the Brazil acquisition was determined using Level 3 inputs and the fair value of the contingent liability which relates to a dispute with Ecopetrol (Note 9) was determined using Level 1 inputs. The disclosure in the paragraph above regarding the fair value of cash and restricted cash is based on Level 1 inputs.
	The Company’s non-recurring fair value measurements include asset retirement obligations. The fair value of an asset retirement obligation is measured by reference to the expected future cash outflows required to satisfy the retirement obligation discounted at the Company’s credit-adjusted risk-free interest rate. The significant level 3 inputs used to calculate such liabilities include estimates of costs to be incurred, the Company’s credit-adjusted risk-free interest rate, inflation rates and estimated dates of abandonment. Accretion expense is recognized over time as the discounted liabilities are accreted to their expected settlement value, while the asset retirement cost is amortized over the estimated productive life of the related assets.
	Credit Risk
	Credit risk arises from the potential that the Company may incur a loss if a counterparty to a financial instrument fails to meet its obligation in accordance with agreed terms. The Company’s financial instruments that are exposed to concentrations of credit risk consist primarily of cash, accounts receivables and foreign currency derivatives. The carrying value of cash, accounts receivable and foreign currency derivatives reflects management’s assessment of credit risk.
	At September 30, 2014, cash and cash equivalents and restricted cash included balances in savings and checking accounts, as well as term deposits and certificates of deposit, placed primarily with financial institutions with strong investment grade ratings or governments, or the equivalent in the Company’s operating areas.
	The Company purchases non-deliverable forward contracts for purposes of fixing exchange rates at which it will purchase or sell Colombian pesos to settle its income tax installment payments. With the exception of these foreign currency derivatives, any foreign currency transactions are conducted on a spot basis with major financial institutions in the Company’s operating areas.
	At September 30, 2014, the Company had the following open foreign currency derivative positions:
	Forward contracts
	Currency		Contract Type	Notional (Millions of Colombian Pesos)	Weighted Average Fixed Rate Received (Colombian Pesos - U.S. Dollars)		Expiration
	Colombian pesos		Buy	15,811.90	1,885		Feb-15
	Colombian pesos		Sell	10,275.30	1,895		Feb-15
	For the nine months ended September 30, 2014, 95% (nine months ended September 30, 2013 - 96%) of the Company's revenue and other income from continuing operations was generated in Colombia.
	Foreign Exchange Risk
	Unrealized foreign exchange gains and losses primarily result from fluctuation of the U.S. dollar to the Colombian peso due to Gran Tierra’s current and deferred tax liabilities, which are monetary liabilities mainly denominated in the local currency of the Colombian operations. As a result, foreign exchange gains and losses must be calculated on conversion to the U.S. dollar functional currency. A strengthening in the Colombian peso against the U.S. dollar results in foreign exchange losses, estimated at $80,000 for each one peso decrease in the exchange rate of the Colombian peso to one U.S. dollar.
	In Colombia, the company receives 100% of its revenues in U.S. dollars and the majority of its capital expenditures are in U.S. dollars or are based on U.S. dollar prices. In Brazil, prices for oil are in U.S. dollars, but revenues are received in local currency translated according to current exchange rates. The majority of the Company's capital expenditures within Brazil are based on U.S. dollar prices, but are paid in local currency translated according to current exchange rates. In Peru, capital expenditures are based on U.S. dollar prices and may be paid in local currency or U.S. dollars.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Discontinued Operations	'
	Discontinued Operations
	During the three months ended June 30, 2014, the Company completed the sale of its Argentina business unit and the discontinued operations criteria of Accounting Standards Codification ("ASC") 205-20, “Discontinued Operations” were met. Therefore, the results of the Company’s Argentina business unit are reflected separately as loss from discontinued operations, net of income taxes in the interim unaudited condensed consolidated statement of operations for the three and nine months ended September 30, 2014 and 2013, on a line immediately after “Income from continuing operations.” Additionally, cash flows of the Company’s Argentina business unit are reflected separately in the interim unaudited condensed consolidated statement of cash flows for the three and nine months ended September 30, 2014 and 2013 as cash provided by or used in operating and investing activities of discontinued operations. Amounts for 2013 have been reclassified to conform to the 2014 presentation. The reclassifications had no effect on net income. See Note 3, “Discontinued Operations,” for additional disclosure. The Company did not recognize depletion, depreciation and accretion expenses subsequent to May 29, 2014, the date the assets were classified as held for sale.
Marketable Securities	'
	Marketable Securities
	The Company acquired investments in marketable securities in connection with the sale of its Argentina business unit. Marketable securities were classified as trading securities, in accordance with ASC 320, “Investments – Debt and Equity Securities”, and are recorded in the consolidated balance sheet at fair value. The Company classifies trading securities as current or non-current based on the intent of management, the nature of the trading securities and whether they are readily available for use in current operations. Gains or losses on trading securities are recorded in the statement of operations as financial instruments gains or losses.
Foreign Currency Derivatives	'
	Foreign Currency Derivatives
	The Company purchases Colombian peso non-deliverable forward contracts for purposes of fixing exchange rates at which it will purchase or sell Colombian pesos to settle its income tax installment payments. The Company does not intend to issue or hold derivative financial instruments for speculative trading purposes.
	The Company records derivative instruments on the balance sheet as either an asset or liability measured at fair value. The accounting for changes in the fair value of a derivative instrument depends on the intended use of the derivative and the resulting designation, which is established at the inception of a derivative. Generally because of the short-term nature of the contracts and their limited use, the Company does not apply hedge accounting, and changes in the fair value of those contracts are reflected in net income as financial instrument gains or losses in the interim unaudited condensed consolidated statement of operations. Cash settlements of the Company's derivative arrangements are classified as operating cash flows.
	The fair value of foreign currency derivatives is based on the estimated maturity value of the foreign exchange non-deliverable forward contracts, using applicable forward exchange rates. The most significant variable to the cash flow calculations is the estimation of forward foreign exchange rates. The resulting net future cash inflows or outflows at maturity of the contracts are the net value of the contract.
Recently Issued Accounting Pronouncements	'
	Recently Adopted Accounting Pronouncements
	Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is fixed at the Reporting Date
	In February 2013, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2013- 04, “Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is fixed at the Reporting Date”. The ASU provides guidance for the recognition, measurement, and disclosure of obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date. Examples of obligations within the scope of this update include debt arrangements, other contractual obligations, and settled litigation and judicial rulings. The ASU was effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The implementation of this update did not materially impact the Company’s consolidated financial position, results of operations, cash flows or disclosure.
	Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists
	In July 2013, the FASB issued ASU 2013-11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists". The ASU provides guidance on the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The ASU was effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The implementation of this update did not materially impact the Company’s consolidated financial position, results of operations, cash flows, or disclosure.
	Recently Issued Accounting Pronouncements
	Revenue from Contracts with Customers
	In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers". The ASU creates a single source of revenue guidance for all companies in all industries and requires revenue recognition to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 sets forth a new revenue recognition model that requires identifying the contract, identifying the performance obligations, determining the transaction price, allocating the transaction price to performance obligations and recognizing the revenue upon satisfaction of performance obligations. The amendments in the ASU can be applied either retrospectively to each prior reporting period presented or retrospectively with the cumulative effect of initially applying the update recognized at the date of the initial application along with additional disclosures. The ASU will be effective for fiscal years, and interim periods within those years, beginning after December 15, 2016. The Company is currently assessing the impact the new standard will have on its consolidated financial position, results of operations, cash flows, and disclosure.

Discontinued_Operations_Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]	'
Financial disclosures of discontinued operations	'
	Revenue and other income and loss from discontinued operations for the three and nine months ended September 30, 2014, and 2013, were as follows:
			Three Months Ended September 30,					Nine Months Ended September 30,
	(Thousands of U.S. Dollars)		2014		2013			2014			2013
	Revenue and other income		$	—	$	18,316		$	31,985		$	55,335
	Loss from operations of discontinued operations before income taxes		$	—	$	(4,163	)	$	(6,252	)	$	(6,253	)
	Income tax expense		—		(2,993		)	(1,458		)	(4,791		)
	Loss from operations of discontinued operations		—		(7,156		)	(7,710		)	(11,044		)
	Loss on sale before income taxes		—		—			(18,235		)	—
	Income tax expense		—		—			(1,045		)	—
	Loss on sale		—		—			(19,280		)	—
	Loss from discontinued operations, net of income taxes		$	—	$	(7,156	)	$	(26,990	)	$	(11,044	)
	At December 31, 2013, assets and liabilities related to discontinued operations were as follows:
		As at
	(Thousands of U.S. Dollars)	December 31, 2013
	Current assets (1)	$	39,125
	Property, plant and equipment	94,446
	Other long-term assets	1,839
		$	135,410
	Current liabilities	$	37,612
	Long-term liabilities	9,755
		$	47,367
	(1) Included cash of $21.2 million.

Segment_and_Geographic_Reporti1

Segment and Geographic Reporting (Tables)	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
Reportable Geographic Segments	'
	The following tables present information on the Company’s reportable segments and other activities:
		Three Months Ended September 30, 2014
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	153,815	$	—		$	7,702		$	—		$	161,517
	Interest income	98		1			433			240			772
	Depletion, depreciation, accretion and impairment	51,144		109			2,429			254			53,936
	Depletion, depreciation, accretion and impairment - per unit of production	28.31		—			26.3			—			28.4
	Income (loss) from continuing operations before income taxes	81,258		(3,345		)	1,746			(8,957		)	70,702
	Segment capital expenditures	50,785		40,730			3,377			527			95,419
		Three Months Ended September 30, 2013
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	164,241	$	—		$	6,584		$	—		$	170,825
	Interest income	111		1			281			126			519
	Depletion, depreciation, accretion and impairment	46,821		73			4,129			246			51,269
	Depletion, depreciation, accretion and impairment - per unit of production	27.48		—			59.72			—			28.92
	Income (loss) from continuing operations before income taxes	89,215		(1,404		)	(337		)	(4,666		)	82,808
	Segment capital expenditures (1)	39,608		11,063			(22,500		)	289			28,460
		Nine Months Ended September 30, 2014
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	438,100	$	—		$	22,410		$	—		$	460,510
	Interest income	419		1			1,292			448			2,160
	Depletion, depreciation, accretion and impairment	131,742		420			7,249			726			140,137
	Depletion, depreciation, accretion and impairment - per unit of production	26.7		—			29.24			—			27.05
	Income (loss) from continuing operations before income taxes	229,750		(7,811		)	7,446			(19,331		)	210,054
	Segment capital expenditures	147,016		103,535			17,176			1,132			268,859
		Nine Months Ended September 30, 2013
	(Thousands of U.S. Dollars, except per unit of production amounts)	Colombia		Peru			Brazil			All Other			Total
	Oil and natural gas sales	$	488,577	$	—		$	18,738		$	—		$	507,315
	Interest income	415		27			292			456			1,190
	Depletion, depreciation, accretion and impairment	141,141		272			15,143			767			157,323
	Depletion, depreciation, accretion and impairment - per unit of production	27.58		—			75.74			—			29.59
	Income (loss) from continuing operations before income taxes	275,353		(4,984		)	(3,663		)	(12,337		)	254,369
	Segment capital expenditures (1)	118,758		59,911			12,021			528			191,218
	(1) In the third quarter of 2013, segment capital expenditures were net of proceeds of $54.0 million relating to termination of a farm-in agreement in Brazil. Additionally, segment capital expenditures for the nine months ended September 30, 2013, were net of proceeds of $1.5 million relating to the Company's sale of its 15% working interest in the Mecaya Block in Colombia (Note 5).
Long-lived Assets by Geographical Area	'
		As at September 30, 2014
	(Thousands of U.S. Dollars)	Colombia		Peru			Brazil			All Other			Total Excluding Discontinued Operations		Discontinued Operations		Total
	Property, plant and equipment	$	865,331	$	281,646		$	143,938		$	3,368		$	1,294,283	$	—	$	1,294,283
	Goodwill	102,581		—			—			—			102,581		—		102,581
	All other assets	264,064		31,439			19,989			211,090			526,582		—		526,582
	Total Assets	$	1,231,976	$	313,085		$	163,927		$	214,458		$	1,923,446	$	—	$	1,923,446
		As at December 31, 2013
	(Thousands of U.S. Dollars)	Colombia		Peru			Brazil			All Other			Total Excluding Discontinued Operations		Discontinued Operations		Total
	Property, plant and equipment	$	850,359	$	178,531		$	133,874		$	2,962		$	1,165,726	$	94,446	$	1,260,172
	Goodwill	102,581		—			—			—			102,581		—		102,581
	All other assets	233,336		24,240			24,477			218,780			500,833		40,964		541,797
	Total Assets	$	1,186,276	$	202,771		$	158,351		$	221,742		$	1,769,140	$	135,410	$	1,904,550

Property_Plant_and_Equipment_a1

Property, Plant and Equipment and Inventory (Tables)	9 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Abstract]	'
Schedule of Property, Plant and Equipment	'
	Property, Plant and Equipment
		As at September 30, 2014							As at December 31, 2013
	(Thousands of U.S. Dollars)	Cost		Accumulated			Net book value		Cost		Accumulated			Net book value
				depletion,							depletion,
				depreciation							depreciation
				and							and
				impairment							impairment
	Oil and natural gas properties
	Proved	$	1,927,314	$	(1,159,207	)	$	768,107	$	1,799,544	$	(1,005,475	)	$	794,069
	Unproved	516,657		—			516,657		456,001		—			456,001
		2,443,971		(1,159,207		)	1,284,764		2,255,545		(1,005,475		)	1,250,070
	Furniture and fixtures and leasehold improvements	9,202		(7,028		)	2,174		8,919		(6,568		)	2,351
	Computer equipment	13,732		(6,820		)	6,912		14,786		(7,605		)	7,181
	Automobiles	802		(369		)	433		1,381		(811		)	570
	Total Property, Plant and Equipment	$	2,467,707	$	(1,173,424	)	$	1,294,283	$	2,280,631	$	(1,020,459	)	$	1,260,172

Share_Capital_Tables

Share Capital (Tables)	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
RSU's and Stock options outstanding	'
	The following table provides information about RSU and stock option activity for the nine months ended September 30, 2014:
		RSUs			Options
		Number of Outstanding Share Units			Number of Outstanding Options			Weighted Average Exercise Price $/Option
	Balance, December 31, 2013	922,045			15,668,458			5.41
	Granted	903,205			2,407,730			7.06
	Exercised	(415,538	)		(3,029,853	)		(3.68	)
	Forfeited	(50,980	)		(197,676	)		(6.59	)
	Expired	—			(720,724	)		(7.12	)
	Balance, September 30, 2014	1,358,732			14,127,935			5.96
Amounts recognized for stock-based compensation	'
	The amounts recognized for stock-based compensation were as follows:
	(Thousands of U.S. Dollars)		Three Months Ended September 30,								Nine Months Ended September 30,
			2014				2013				2014			2013
	Compensation costs for stock options		$	1,961			$	2,133			$	5,824		$	6,314
	Compensation costs for RSUs		326				1,282				3,967			1,901
			2,287				3,415				9,791			8,215
	Less: Stock-based compensation costs capitalized		(278		)		(1,718		)		(2,100		)	(2,102		)
	Stock-based compensation costs expensed		$	2,009			$	1,697			$	7,691		$	6,113
Weighted average shares outstanding	'
			Three Months Ended September 30,						Nine Months Ended September 30,
			2014			2013			2014			2013
	Weighted average number of common and exchangeable shares outstanding		285,576,898			283,092,224			284,203,679			282,687,871
	Weighted average shares issuable pursuant to stock options		8,117,355			12,428,489			9,399,930			10,823,968
	Weighted average shares assumed to be purchased from proceeds of stock options		(5,634,652	)		(9,494,194	)		(6,034,262	)		(7,691,832	)
	Weighted average number of diluted common and exchangeable shares outstanding		288,059,601			286,026,519			287,569,347			285,820,007

Asset_Retirement_Obligation_Ta

Asset Retirement Obligation (Tables)	9 Months Ended
	Sep. 30, 2014
Asset Retirement Obligation [Abstract]	'
Changes in Asset Retirement Obligations	'
	Changes in the carrying amounts of the asset retirement obligation associated with the Company’s oil and natural gas properties were as follows:
		Nine Months Ended			Year Ended
	(Thousands of U.S. Dollars)	September 30, 2014			December 31, 2013
	Balance, beginning of period	$	21,973		$	18,292
	Settlements	(211		)	(2,068		)
	Liability incurred	10,262			2,623
	Liabilities associated with the Argentina business unit sold (Note 3)	(10,170		)	—
	Foreign exchange	(14		)	(25		)
	Accretion	1,022			1,279
	Revisions in estimated liability	4,056			1,872
	Balance, end of period	$	26,918		$	21,973
	Asset retirement obligation - current	$	7,353		$	518
	Asset retirement obligation - long-term	19,565			21,455
	Balance, end of period	$	26,918		$	21,973

Taxes_Tables

Taxes (Tables)	9 Months Ended
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
Income tax expense reported reconciliation to computed statutory rate	'
	The income tax expense reported differs from the amount computed by applying the U.S. statutory rate to income from continuing operations before income taxes for the following reasons:
		Nine Months Ended September 30,
	(Thousands of U.S. Dollars)	2014			2013
	Income (loss) from continuing operations before income taxes
	United States	$	(16,450	)	$	(8,488	)
	Foreign	226,504			262,857
		210,054			254,369
		35		%	35		%
	Income tax expense from continuing operations expected	73,519			89,029
	Foreign currency translation adjustments	(1,464		)	(7,263		)
	Impact of foreign taxes	(3,361		)	(3,388		)
	Other local taxes	3,192			1,497
	Stock-based compensation	2,155			1,887
	Increase in valuation allowance	2,146			17,975
	Non-deductible third party royalty in Colombia	7,554			8,812
	Other permanent differences	873			(3,977		)
	Total income tax expense from continuing operations	$	84,614		$	104,572
	Current income tax expense from continuing operations
	United States	$	990		$	813
	Foreign	82,193			127,253
		83,183			128,066
	Deferred income tax expense (recovery) from continuing operations
	Foreign	1,431			(23,494		)
	Total income tax expense from continuing operations	$	84,614		$	104,572
Deferred tax assets and liabilities	'
		As at
	(Thousands of U.S. Dollars)	September 30, 2014			31-Dec-13
	Deferred Tax Assets
	Tax benefit of operating loss carryforwards	$	36,367		$	47,154
	Tax basis in excess of book basis	40,257			59,168
	Foreign tax credits and other accruals	19,917			34,894
	Tax benefit of capital loss carryforwards	29,114			4,769
	Deferred tax assets before valuation allowance	125,655			145,985
	Valuation allowance	(122,860		)	(142,322		)
		$	2,795		$	3,663
	Deferred tax assets - current	$	1,099		$	2,256
	Deferred tax assets - long-term	1,696			1,407
		2,795			3,663
	Deferred tax liabilities - current	(1,461		)	(1,193		)
	Deferred tax liabilities - long-term	(168,495		)	(177,082		)
		(169,956		)	(178,275		)
	Net Deferred Tax Liabilities	$	(167,161	)	$	(174,612	)
Schedule of Unrecognized Tax Benefits Roll Forward	'
	Changes in the Company's unrecognized tax benefit relating to continuing operations are as follows:
		Nine Months Ended September 30,
		2014			2013
	(Thousands of U.S. Dollars)
	Unrecognized tax benefit relating to continuing operations at beginning of period	$	2,900		$	5,900
	Increases for positions relating to prior year	1,200			—
	Decreases for positions relating to prior year	—			(3,200		)
	Unrecognized tax benefit relating to continuing operations at end of period	$	4,100		$	2,700

Financial_Instruments_Fair_Val1

Financial Instruments, Fair Value Measurements and Credit Risk (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value of Foreign Currency Derivatives, Contingent Consideration and Contingent Liability	'
	The fair value of the trading securities, foreign currency derivative assets and liabilities, contingent consideration and the contingent liability related to the Ecopetrol dispute at September 30, 2014, and December 31, 2013, were as follows:
			As at
	(Thousands of U.S. Dollars)		September 30, 2014			December 31, 2013
	Trading securities (Note 3)		$	11,711		$	—
	Foreign currency derivative asset		414			—
			$	12,125		—
	Foreign currency derivative liability		$	652		$	—
	Contingent consideration liability		1,061			1,061
	Contingent liability (Note 9)		4,400			4,400
			$	6,113		$	5,461
Gains Associated with Foreign Currency Derivatives	'
	The following table presents gains or losses on financial instruments recognized in the accompanying interim unaudited condensed consolidated statements of operations:
	(Thousands of U.S. Dollars)	Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
	Trading securities loss	$	2,540		$	—		$	2,201		$	—
	Foreign currency derivatives loss (gain)	250			—			(4,424		)	—
		$	2,790		$	—		$	(2,223	)	$	—
Open Foreign Currency Derivative Positions	'
	At September 30, 2014, the Company had the following open foreign currency derivative positions:
	Forward contracts
	Currency		Contract Type	Notional (Millions of Colombian Pesos)	Weighted Average Fixed Rate Received (Colombian Pesos - U.S. Dollars)		Expiration
	Colombian pesos		Buy	15,811.90	1,885		Feb-15
	Colombian pesos		Sell	10,275.30	1,895		Feb-15

Discontinued_Operations_Revenu

Discontinued Operations - Revenue and Loss from Discontinued Operations (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Discontinued Operations and Disposal Groups [Abstract]	'	'	'	'
Revenue and other income	$0	$18,316	$31,985	$55,335
Loss from operations of discontinued operations before income taxes	0	-4,163	-6,252	-6,253
Income tax expense	0	-2,993	-1,458	-4,791
Loss from operations of discontinued operations	0	-7,156	-7,710	-11,044
Loss on sale before income taxes	0	0	-18,235	0
Income tax expense	0	0	-1,045	0
Loss on sale	0	0	-19,280	0
Loss from discontinued operations, net of income taxes	$0	($7,156)	($26,990)	($11,044)

Discontinued_Operations_Assets

Discontinued Operations - Assets and Liabilities Related to Discontinued Operations (Details) (USD $)	Dec. 31, 2013
Discontinued Operations and Disposal Groups [Abstract]	'
Current assets	$39,125,000	[1]
Property, plant and equipment	94,446,000
Other long-term assets	1,839,000
Total assets	135,410,000
Current liabilities	37,612,000
Long-term liabilities	9,755,000
Total liabilities	47,367,000
Cash	$21,200,000
[1]	Included cash of $21.2 million.

Discontinued_Operations_Narrat

Discontinued Operations - Narrative (Details) (USD $)	12 Months Ended	0 Months Ended		0 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Jun. 25, 2014	Jun. 25, 2014	Jun. 25, 2014	Jun. 25, 2014
	Argentina [Member]	Argentina Business Unit [Member]	Argentina Business Unit [Member]	Argentina Business Unit [Member]	Argentina Business Unit [Member]
				GTE ULC and PCESA [Member]	Petroco [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'
Aggregate consideration	'	'	$69.30	'	'
Cash received	'	55.4	'	44.8	10.6
Value of shares received	'	'	'	13.9	'
Impairment loss	$30.80	'	'	'	'

Segment_and_Geographic_Reporti2

Segment and Geographic Reporting - Reportable Segments (Details) (USD $)	3 Months Ended			9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013		Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]	'	'		'	'
Oil and natural gas sales	$161,517	$170,825		$460,510	$507,315
Interest income	772	519		2,160	1,190
Depletion, depreciation, accretion and impairment	53,936	51,269		140,137	157,323
Income (loss) from continuing operations before income taxes	70,702	82,808		210,054	254,369
Continuing Operations [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Oil and natural gas sales	161,517	170,825		460,510	507,315
Interest income	772	519		2,160	1,190
Depletion, depreciation, accretion and impairment	53,936	51,269		140,137	157,323
Depletion, depreciation, accretion and impairment - per unit of production	28.4	28.92		27.05	29.59
Income (loss) from continuing operations before income taxes	70,702	82,808		210,054	254,369
Segment capital expenditures (1)	95,419	28,460	[1]	268,859	191,218	[1]
Colombia [Member] | Continuing Operations [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Oil and natural gas sales	153,815	164,241		438,100	488,577
Interest income	98	111		419	415
Depletion, depreciation, accretion and impairment	51,144	46,821		131,742	141,141
Depletion, depreciation, accretion and impairment - per unit of production	28.31	27.48		26.7	27.58
Income (loss) from continuing operations before income taxes	81,258	89,215		229,750	275,353
Segment capital expenditures (1)	50,785	39,608		147,016	118,758
Peru [Member] | Continuing Operations [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Oil and natural gas sales	0	0		0	0
Interest income	1	1		1	27
Depletion, depreciation, accretion and impairment	109	73		420	272
Depletion, depreciation, accretion and impairment - per unit of production	0	0		0	0
Income (loss) from continuing operations before income taxes	-3,345	-1,404		-7,811	-4,984
Segment capital expenditures (1)	40,730	11,063		103,535	59,911
Brazil [Member] | Continuing Operations [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Oil and natural gas sales	7,702	6,584		22,410	18,738
Interest income	433	281		1,292	292
Depletion, depreciation, accretion and impairment	2,429	4,129		7,249	15,143
Depletion, depreciation, accretion and impairment - per unit of production	26.3	59.72		29.24	75.74
Income (loss) from continuing operations before income taxes	1,746	-337		7,446	-3,663
Segment capital expenditures (1)	3,377	-22,500		17,176	12,021
All Other [Member] | Continuing Operations [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Oil and natural gas sales	0	0		0	0
Interest income	240	126		448	456
Depletion, depreciation, accretion and impairment	254	246		726	767
Depletion, depreciation, accretion and impairment - per unit of production	0	0		0	0
Income (loss) from continuing operations before income taxes	-8,957	-4,666		-19,331	-12,337
Segment capital expenditures (1)	$527	$289		$1,132	$528
[1]	In the third quarter of 2013, segment capital expenditures were net of proceeds of $54.0 million relating to termination of a farm-in agreement in Brazil. Additionally, segment capital expenditures for the nine months ended September 30, 2013, were net of proceeds of $1.5 million relating to the Company's sale of its 15% working interest in the Mecaya Block in Colombia (Note 5).

Segment_and_Geographic_Reporti3

Segment and Geographic Reporting - Assets (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	$1,294,283	$1,260,172
Goodwill	102,581	102,581
All other assets	526,582	541,797
Total Assets	1,923,446	1,904,550
Continuing Operations [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	1,294,283	1,165,726
Goodwill	102,581	102,581
All other assets	526,582	500,833
Total Assets	1,923,446	1,769,140
Continuing Operations [Member] | Colombia [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	865,331	850,359
Goodwill	102,581	102,581
All other assets	264,064	233,336
Total Assets	1,231,976	1,186,276
Continuing Operations [Member] | Peru [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	281,646	178,531
Goodwill	0	0
All other assets	31,439	24,240
Total Assets	313,085	202,771
Continuing Operations [Member] | Brazil [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	143,938	133,874
Goodwill	0	0
All other assets	19,989	24,477
Total Assets	163,927	158,351
Continuing Operations [Member] | All Other [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	3,368	2,962
Goodwill	0	0
All other assets	211,090	218,780
Total Assets	214,458	221,742
Discontinued Operations [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property, plant and equipment	0	94,446
Goodwill	0	0
All other assets	0	40,964
Total Assets	$0	$135,410

Segment_and_Geographic_Reporti4

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

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

In Thousands, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2014

Jun. 30, 2013

Colombia [Member]

Colombia [Member]

Colombia [Member]

Colombia [Member]

Colombia [Member]

Colombia [Member]

Colombia [Member]

Colombia [Member]

Colombia [Member]

Brazil [Member]

Colombia [Member]

Colombia [Member]

Ecopetrol [Member]

Ecopetrol [Member]

Ecopetrol [Member]

Ecopetrol [Member]

Hocol Petroleum Limited [Member]

Other Customer Number One [Member]

Other Customer Number One [Member]

Other Customer Number One [Member]

Other Customer Number One [Member]

customer

Mecaya Block [Member]

Concentration Risk [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from sale of oil and gas properties

$0

($55,524)

'

'

'

'

'

'

'

'

'

($54,000)

'

($1,500)

Working interest sold, percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

15.00%

Number of major customers

'

'

'

'

'

'

'

'

'

'

'

'

3

'

Number of other significant customers

'

'

'

'

'

'

'

'

'

'

'

'

1

'

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

'

'

37.00%

61.00%

46.00%

57.00%

11.00%

38.00%

31.00%

38.00%

32.00%

'

'

'

Property_Plant_and_Equipment_a2

Property, Plant and Equipment and Inventory (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'
Cost	$2,467,707	$2,280,631
Accumulated depletion, depreciation and impairment	-1,173,424	-1,020,459
Total Property, Plant and Equipment (Note 5)	1,294,283	1,260,172
Proved [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	1,927,314	1,799,544
Accumulated depletion, depreciation and impairment	-1,159,207	-1,005,475
Total Property, Plant and Equipment (Note 5)	768,107	794,069
Unproved [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	516,657	456,001
Accumulated depletion, depreciation and impairment	0	0
Total Property, Plant and Equipment (Note 5)	516,657	456,001
Oil and natural gas properties depletable base under full cost accounting [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	2,443,971	2,255,545
Accumulated depletion, depreciation and impairment	-1,159,207	-1,005,475
Total Property, Plant and Equipment (Note 5)	1,284,764	1,250,070
Furniture and fixtures and leasehold improvements [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	9,202	8,919
Accumulated depletion, depreciation and impairment	-7,028	-6,568
Total Property, Plant and Equipment (Note 5)	2,174	2,351
Computer equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	13,732	14,786
Accumulated depletion, depreciation and impairment	-6,820	-7,605
Total Property, Plant and Equipment (Note 5)	6,912	7,181
Automobiles [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Cost	802	1,381
Accumulated depletion, depreciation and impairment	-369	-811
Total Property, Plant and Equipment (Note 5)	$433	$570

Property_Plant_and_Equipment_a3

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

3 Months Ended

9 Months Ended

3 Months Ended

3 Months Ended

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

31-May-14

30-May-14

31-May-14

30-May-14

31-May-14

30-May-14

Sep. 30, 2014

Jun. 30, 2013

Sep. 30, 2013

Colombia [Member]

Colombia [Member]

Argentina [Member]

Peru [Member]

Peru [Member]

Brazil [Member]

Brazil [Member]

Brazil [Member]

Brazil [Member]

Brazil [Member]

Brazil [Member]

Brazil [Member]

Brazil [Member]

Brazil [Member]

Brazil [Member]

Four out of Seven Blocks Unproved Oil and Gas Properties [Member]

Mecaya Block [Member]

Reconcavo Basin [Member]

Proved Reserve [Member]

Proved Reserve [Member]

Proved and Probable Reserves [Member]

Proved and Probable Reserves [Member]

Probable and Possible [Member]

Probable and Possible [Member]

Brazil [Member]

Colombia [Member]

Brazil [Member]

Boe

Boe

Boe

Boe

Boe

Boe

Property, Plant and Equipment [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Depreciation and depletion

$49,900,000

$51,500,000

$140,400,000

$150,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Impairment of oil and gas properties

'

'

'

'

'

'

'

'

'

'

'

'

'

2,000,000

'

'

'

'

'

'

'

'

'

Energy reserves (in BOE)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,000,000

1,700,000

4,900,000

3,300,000

7,200,000

5,000,000

'

'

'

Proceeds from sale of oil and gas properties

'

'

0

-55,524,000

'

'

'

'

'

'

'

'

-54,000,000

'

'

'

'

'

'

'

'

-1,500,000

-54,000,000

Working interest sold, percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

15.00%

'

Unproven properties relating to four blocks

1,294,283,000

'

1,294,283,000

'

1,260,172,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,600,000

'

'

Unproved assets by cost center

516,700,000

'

516,700,000

'

437,800,000

170,200,000

176,100,000

18,200,000

280,400,000

177,500,000

66,100,000

84,200,000

'

'

'

'

'

'

'

'

'

'

'

Crude oil inventories

11,500,000

'

11,500,000

'

11,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Supplies

$2,400,000

'

$2,400,000

'

$2,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Share_Capital_RSU_and_Stock_Op

Share Capital - RSU and Stock Option Activity (Details) (USD $)	9 Months Ended
	Sep. 30, 2014
Number of Outstanding Options	'
Balance (in shares)	15,668,458
Granted (in shares)	2,407,730
Exercised (in shares)	-3,029,853
Forfeited (in shares)	-197,676
Expired (in shares)	-720,724
Balance (in shares)	14,127,935
Weighted Average Exercise Price $/Option	'
Weighted Average Exercise Price $/Option, beginning balance (in dollars per share)	$5.41
Weighted Average Exercise Price $/Option, Granted (in dollars per share)	$7.06
Weighted Average Exercise Price $/Options, Exercised (in dollars per share)	($3.68)
Weighted Average Exercise Price $/Options, Forfeited (in dollars per share)	($6.59)
Weighted Average Exercise Price $/Options, Expired (in dollars per share)	($7.12)
Weighted Average Exercise Price $/Option, ending balance (in dollars per share)	$5.96
RSUs [Member]	'
Number of Outstanding Share Units	'
Balance (in shares)	922,045
Granted (in shares)	903,205
Exercised (in shares)	-415,538
Forfeited (in shares)	-50,980
Expired (in shares)	0
Balance (in shares)	1,358,732

Share_Capital_Allocation_of_Sh

Share Capital - Allocation of Share Based Compensation (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Compensation cost	$2,287	$3,415	$9,791	$8,215
Less: Stock-based compensation costs capitalized	-278	-1,718	-2,100	-2,102
Stock-based compensation costs expensed	2,009	1,697	7,691	6,113
Stock Options [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Compensation cost	1,961	2,133	5,824	6,314
RSUs [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Compensation cost	$326	$1,282	$3,967	$1,901

Share_Capital_Weighted_Average

Share Capital - Weighted Average Shares (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'	'
Weighted average number of common and exchangeable shares outstanding	285,576,898	283,092,224	284,203,679	282,687,871
Weighted average shares issuable pursuant to stock options	8,117,355	12,428,489	9,399,930	10,823,968
Weighted average shares assumed to be purchased from proceeds of stock options	-5,634,652	-9,494,194	-6,034,262	-7,691,832
Weighted average number of diluted common and exchangeable shares outstanding	288,059,601	286,026,519	287,569,347	285,820,007

Share_Capital_Narrative_Detail

Share Capital - Narrative (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
			vote
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]	'	'	'	'	'
Authorized share capital	595,000,002	'	595,000,002	'	'
Common stock, authorized	570,000,000	'	570,000,000	'	'
Common shares, par value (in dollars per share)	$0.00	'	$0.00	'	$0.00
Preferred stock, authorized	25,000,000	'	25,000,000	'	'
Preferred stock, par value (in dollars per share)	$0.00	'	$0.00	'	'
Special voting stock-authorized (in shares)	2	'	2	'	'
Special voting stock-par value (in dollars per share)	$0.00	'	$0.00	'	'
Common shares, outstanding	276,018,597	'	276,018,597	'	272,327,810
Stock issued during period upon exercise of stock options (in shares)	'	'	3,029,853	'	'
Proceeds from issuance of shares of Common Stock	'	'	$11,177,000	$3,475,000	'
Votes per common stock	'	'	1	'	'
Common voting shares per exchangeable share (in shares)	'	'	1	'	'
Cash received from exercise of stock options	'	'	'	3,500,000	'
Stock option exercises in period (in shares)	'	'	-3,029,853	'	'
Stock Options [Abstract]	'	'	'	'	'
Stock-based compensation costs expensed	2,009,000	1,697,000	7,691,000	6,113,000	'
Loss from discontinued operations, net of income taxes (Note 3)	0	-7,156,000	-26,990,000	-11,044,000	'
Unrecognized compensation cost related to unvested stock options	8,600,000	'	8,600,000	'	8,100,000
Unvested stock options recognition period	'	'	'2 years 10 months 24 days	'	'
Stock Options [Member]	'	'	'	'	'
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]	'	'	'	'	'
Weighted Average Grant Date Fair Value $/Option, Granted in Period	$2.21	$2.34	$2.50	$2.62	'
Earnings Per Share [Abstract]	'	'	'	'	'
Options excluded from the diluted income per share calculation	6,884,227	3,472,472	6,925,117	5,584,732	'
Stock Options [Member] | General and Administrative Expense [Member]	'	'	'	'	'
Stock Options [Abstract]	'	'	'	'	'
Stock-based compensation costs expensed	2,000,000	1,300,000	6,100,000	5,100,000	'
Stock Options [Member] | Operating Expense [Member]	'	'	'	'	'
Stock Options [Abstract]	'	'	'	'	'
Stock-based compensation costs expensed	0	100,000	300,000	400,000	'
Stock Options [Member] | Discontinued Operations [Member]	'	'	'	'	'
Stock Options [Abstract]	'	'	'	'	'
Stock-based compensation costs expensed	$0	$300,000	$1,300,000	$600,000	'
Gran Tierra Exchangeco Inc [Member]	'	'	'	'	'
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]	'	'	'	'	'
Exchangeable shares outstanding (in shares)	5,687,379	'	5,687,379	'	'
Exchange shares issued during period	'	'	660,934	'	'
Gran Tierra Goldstrike Inc [Member]	'	'	'	'	'
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]	'	'	'	'	'
Exchangeable shares outstanding (in shares)	4,534,127	'	4,534,127	'	'

Asset_Retirement_Obligation_De

Asset Retirement Obligation (Details) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]	'	'
Balance, beginning of period	$21,973,000	$18,292,000
Settlements	-211,000	-2,068,000
Liability incurred	10,262,000	2,623,000
Liabilities associated with the Argentina business unit sold	-10,170,000	0
Foreign exchange	-14,000	-25,000
Accretion	1,022,000	1,279,000
Revisions in estimated liability	4,056,000	1,872,000
Balance, end of period	26,918,000	21,973,000
Asset retirement obligation - current	7,353,000	518,000
Asset retirement obligation - long-term	19,565,000	21,455,000
Balance, end of period	26,918,000	21,973,000
Fair value of legally restricted assets	$2,400,000	$1,900,000

Taxes_Income_Tax_Reconciliatio

Taxes - Income Tax Reconciliation (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income (loss) from continuing operations before income taxes	'	'	'	'
United States	'	'	($16,450)	($8,488)
Foreign	'	'	226,504	262,857
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	70,702	82,808	210,054	254,369
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]	'	'	'	'
Effective income tax rate	'	'	35.00%	35.00%
Income tax expense from continuing operations expected	'	'	73,519	89,029
Foreign currency translation adjustments	'	'	-1,464	-7,263
Impact of foreign taxes	'	'	-3,361	-3,388
Other local taxes	'	'	3,192	1,497
Stock-based compensation	'	'	2,155	1,887
Increase in valuation allowance	'	'	2,146	17,975
Non-deductible third party royalty in Colombia	'	'	7,554	8,812
Other permanent differences	'	'	873	-3,977
Total income tax expense from continuing operations	26,518	42,595	84,614	104,572
Current income tax expense from continuing operations	'	'	'	'
United States	'	'	990	813
Foreign	'	'	82,193	127,253
Total Current income tax expense	'	'	83,183	128,066
Deferred income tax expense (recovery) from continuing operations	'	'	'	'
Foreign	'	'	$1,431	($23,494)

Taxes_Permanent_Differences_Re

Taxes - Permanent Differences Reconciliation (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Income Tax Disclosure [Abstract]	'	'
Tax benefit of operating loss carryforwards	$36,367	$47,154
Tax basis in excess of book basis	40,257	59,168
Foreign tax credits and other accruals	19,917	34,894
Tax benefit of capital loss carryforwards	29,114	4,769
Deferred tax assets before valuation allowance	125,655	145,985
Valuation allowance	-122,860	-142,322
Deferred tax assets, net	2,795	3,663
Deferred tax assets - current	1,099	2,256
Deferred tax assets - long-term	1,696	1,407
Deferred tax liabilities - current	-1,461	-1,193
Deferred tax liabilities - long-term	-168,495	-177,082
Deferred tax liabilities, net	-169,956	-178,275
Net Deferred Tax Liabilities	($167,161)	($174,612)

Taxes_Unrecognized_Tax_Benefit

Taxes - Unrecognized Tax Benefits Rollforward (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]	'	'
Unrecognized tax benefit relating to continuing operations at beginning of period	$2,900	$5,900
Increases for positions relating to prior year	1,200	0
Decrease for positions relating to prior year	0	-3,200
Unrecognized tax benefit relating to continuing operations at end of period	$4,100	$2,700

Taxes_Narrative_Details

Taxes - Narrative (Details) (USD $)	12 Months Ended		3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2014	Mar. 31, 2011	Sep. 30, 2014	Dec. 31, 2013
			Colombia [Member]	Colombia [Member]	Colombia [Member]
			installment
Income Tax Disclosure [Abstract]	'	'	'	'	'
Operating loss carryforwards	$215.40	$122.70	'	'	'
Capital losses before valuation allowance	32.6	227	'	'	'
Net operating loss and capital loss carryforward from foreign subsidiaries	213.8	308.8	'	'	'
Income Tax Examination [Line Items]	'	'	'	'	'
Foreign equity tax payable	'	'	'	$0	$3.30
Equity tax rate (in hundredths)	6.00%	'	'	6.00%	'
Equity tax for foreign operations - Columbia, number of semi-annual installments	'	'	8	'	'
Equity tax for foreign operations - Columbia, assessment term (in years)	'	'	'4 years	'	'

Contingencies_Details

Contingencies (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Sep. 30, 2014	Sep. 30, 2014
			Pending Litigation Escopetrol [Member]	Pending Litigation Escopetrol [Member]	Pending Litigation Moqueta Discovery [Member]	Pending Litigation Royalty, Transportation and Related Costs [Member]
				bbl	bbl
Loss Contingencies [Line Items]	'	'	'	'	'	'
Loss in period in barrels of oil	'	'	'	44,025	'	'
Contingent liability (Note 9)	'	'	$4,400,000	'	$59,700,000	$38,900,000
Threshold by which additional royalty due (barrels)	'	'	'	'	5,000,000	'
Total cumulative production of oil field (barrels)	'	'	'	'	3,700,000	'
Promissory notes provided as collateral for letters of credit	$73,600,000	$52,500,000	'	'	'	'

Financial_Instruments_Fair_Val2

Financial Instruments, Fair Value Measurements and Credit Risk - Fair Value of the Foreign Currency Derivatives, Contingent Consideration and the Contingent Liability (Details) (Ecopetrol Dispute [Member], USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Ecopetrol Dispute [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Trading securities (Note 3)	$11,711	$0
Foreign currency derivative asset	414	0
Assets, Fair Value Disclosure	12,125	0
Foreign currency derivative liability	652	0
Contingent consideration liability	1,061	1,061
Contingent liability (Note 9)	4,400	4,400
Financial and Nonfinancial Liabilities, Fair Value Disclosure	$6,113	$5,461

Financial_Instruments_Fair_Val3

Financial Instruments, Fair Value Measurements and Credit Risk - Gains Recognized in the Statement of Operations (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'	'	'	'
Trading securities loss	$2,540	$0	$2,201	$0
Foreign currency derivatives loss (gain)	250	0	-4,424	0
Gain (Loss) on Derivative Instruments, Net, Pretax	$2,790	$0	($2,223)	$0

Financial_Instruments_Fair_Val4

Financial Instruments, Fair Value Measurements and Credit Risk - Open Foreign Currency Derivative Position (Details) (Foreign Exchange Forward [Member], Forward Contract Expiring February 2015 [Member], COP)	Sep. 30, 2014
In Millions, unless otherwise specified
Long [Member]	'
Derivative [Line Items]	'
Notional amount	15,811.90
Weighted Average Fixed Rate Received	1,885
Short [Member]	'
Derivative [Line Items]	'
Notional amount	10,275.30
Weighted Average Fixed Rate Received	1,895

Financial_Instruments_Fair_Val5

Financial Instruments, Fair Value Measurements and Credit Risk - Narrative (Details) (USD $)	9 Months Ended			0 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2013	Oct. 08, 2012
		Colombia [Member]	Colombia [Member]	Block-Brazil [Member]
		Sales Revenue, Segment [Member]	Sales Revenue, Segment [Member]
		Geographic Concentration Risk [Member]	Geographic Concentration Risk [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'
Participating interest percentage oil and gas property, remaining percentage	'	'	'	30.00%
Concentration risk, percentage	'	95.00%	96.00%	'
Foreign exchange losses, Colombian peso to U.S. dollar	$80	'	'	'