Supplemental Disclosures (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Summary of current accrued liabilities
Other	$ 4,377	$ 2,937
Total accrued liabilities	50,262	25,439
Accrued evaluated and unproved and unevaluated property costs [Member]
Summary of current accrued liabilities
Total accrued liabilities	39,813	18,185
Accrued support equipment and facilities costs [Member]
Summary of current accrued liabilities
Total accrued liabilities	590	216
Accrued cost to issue equity [Member]
Summary of current accrued liabilities
Total accrued liabilities		332
Accrued stock-based compensation [Member]
Summary of current accrued liabilities
Total accrued liabilities	586	2,860
Accrued lease operating expenses [Member]
Summary of current accrued liabilities
Total accrued liabilities	4,506	575
Accrued interest on borrowings under Credit Agreement [Member]
Summary of current accrued liabilities
Total accrued liabilities	43
Accrued asset retirement obligations [Member]
Summary of current accrued liabilities
Total accrued liabilities	$ 347	$ 334