Supplemental Disclosures (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Summary of current accrued liabilities
Other	$ 2,597	$ 2,937
Accrued liabilities	36,259	25,439
Accrued evaluated and unproved and unevaluated property costs [Member]
Summary of current accrued liabilities
Accrued liabilities	29,653	18,185
Accrued support equipment and facilities costs [Member]
Summary of current accrued liabilities
Accrued liabilities		216
Accrued cost to issue equity [Member]
Summary of current accrued liabilities
Accrued liabilities		332
Accrued stock-based compensation [Member]
Summary of current accrued liabilities
Accrued liabilities	1,276	2,860
Accrued lease operating expenses [Member]
Summary of current accrued liabilities
Accrued liabilities	2,272	575
Accrued interest on bank borrowings under Credit Agreement [Member]
Summary of current accrued liabilities
Accrued liabilities	118
Accrued asset retirement obligations [Member]
Summary of current accrued liabilities
Accrued liabilities	$ 343	$ 334