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 Colombia [Member]	Dec. 31, 2013 Colombia [Member]	Dec. 31, 2013 Argentina [Member]	Sep. 30, 2014 Peru [Member]	Dec. 31, 2013 Peru [Member]	Sep. 30, 2014 Brazil [Member]	Dec. 31, 2013 Brazil [Member]	Sep. 30, 2013 Brazil [Member]	Jun. 30, 2013 Brazil [Member]	May 31, 2014 Brazil [Member] Proved Reserve [Member] Boe	May 30, 2014 Brazil [Member] Proved Reserve [Member] Boe	May 31, 2014 Brazil [Member] Proved and Probable Reserves [Member] Boe	May 30, 2014 Brazil [Member] Proved and Probable Reserves [Member] Boe	May 31, 2014 Brazil [Member] Probable and Possible [Member] Boe	May 30, 2014 Brazil [Member] Probable and Possible [Member] Boe	Sep. 30, 2014 Four out of Seven Blocks Unproved Oil and Gas Properties [Member] Brazil [Member]	Jun. 30, 2013 Mecaya Block [Member] Colombia [Member]	Sep. 30, 2013 Reconcavo Basin [Member] Brazil [Member]
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