Supplemental Disclosures (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Summary of current accrued liabilities
Total accrued liabilities	$ 63,987	$ 59,179
Other	3,586	2,410
Accrued evaluated and unproved and unevaluated property costs [Member]
Summary of current accrued liabilities
Total accrued liabilities	52,605	45,592
Accrued support equipment and facilities costs [Member]
Summary of current accrued liabilities
Total accrued liabilities	0	1,382
Accrued stock-based compensation [Member]
Summary of current accrued liabilities
Total accrued liabilities	56	65
Accrued lease operating expenses [Member]
Summary of current accrued liabilities
Total accrued liabilities	6,251	5,218
Accrued interest on borrowings under Credit Agreement [Member]
Summary of current accrued liabilities
Total accrued liabilities	141	255
Accrued asset retirement obligations [Member]
Summary of current accrued liabilities
Total accrued liabilities	175	660
Accrued partners' share of joint interest charges [Member]
Summary of current accrued liabilities
Total accrued liabilities	$ 1,173	$ 3,597