Supplementary Information on Oil and Natural Gas Activities (Unaudited) - Schedule of Standardized Measure of Discounted Future Net Cash Flows Relating to Estimated Proved Oil, Natural Gas and Natural Gas Liquids Reserves (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Future net cash flows relating to estimated proved oil, natural gas and natural gas liquids reserves based on the standardized measure
Future cash inflows	$ 123,889	$ 288,705	$ 814,394
Future production and development costs	(86,103)	(186,053)	(257,016)
Future net cash flows	37,786	102,652	557,378
10% annual premium (discount) for estimated timing of cash flows	1,164	(45,077)	(192,094)
Standardized measure of discounted future net cash flows	$ 38,950	$ 57,575	$ 365,284	$ 276,633