Acquisitions and Divestitures - Divestiture (Woodford and Mississippian Lime) (Details) $ in Thousands, Mcfe in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Mar. 31, 2016 USD ($)	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)	Jun. 04, 2015 USD ($)	Dec. 31, 2014 Mcfe
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of oil and gas properties				$ 23,200
Sale of oil and gas properties	$ 7,000	$ 7,000	$ 0
Woodford and Mississippian Lime
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds from sale of a majority of interests					$ 260,200
Proved reserves | Mcfe						227
Estimated proved reserves attributable to Sold Assets (percent of total)						57.00%