Related Party Transactions (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Related Party Transaction [Line Items]
Accounts payable, Peru drilling program	$ 82,189,000	$ 76,023,000
Cost incurred	2,800,000
Director - Sublease related party [Member]
Related Party Transaction [Line Items]
Related party transaction initiation date	2011-02-01
Related party transaction expiration date	Jan. 30, 2013
Terms of the sublease agreement	The term of the sublease runs from February 1, 2009 to August 31, 2011 and the sublease payment is 8,800 per month plus approximately 4,500 for operating and other expenses.
Monthly sublease payment due for office space	4,300
Monthly sublease operating and other expenses due for office space	4,500
Director - Peru drilling program related party [Member]
Related Party Transaction [Line Items]
Related party transaction initiation date	2010-08-03
Capitalization of Peru drilling program		800,000
Accounts payable, Peru drilling program		$ 800,000