Segment and Geographic Reporting - Reportable Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	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	28.40	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		26.70	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	0.00	0.00		0.00	0.00
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	26.30	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	0.00	0.00		0.00	0.00
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).