Fair Value Measurements (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Assets (Liabilities)
Oil, natural gas and NGL derivatives	$ 23,460	$ 55,549
Oil, natural gas and NGL derivatives	0	0
Fair value on a recurring basis
Assets (Liabilities)
Oil, natural gas and NGL derivatives	23,847	55,549
Oil, natural gas and NGL derivatives	(387)
Total	23,460	55,549
Fair value on a recurring basis | Level 1
Assets (Liabilities)
Oil, natural gas and NGL derivatives	0	0
Oil, natural gas and NGL derivatives	0
Fair value on a recurring basis | Level 2
Assets (Liabilities)
Oil, natural gas and NGL derivatives	23,847	55,549
Oil, natural gas and NGL derivatives	(387)
Total	23,460	55,549
Fair value on a recurring basis | Level 3
Assets (Liabilities)
Oil, natural gas and NGL derivatives	0	$ 0
Oil, natural gas and NGL derivatives	$ 0