Acquisitions and Divestitures - Divestiture (Details) $ in Thousands, Mcfe in Billions	1 Months Ended		3 Months Ended		9 Months Ended
	Mar. 31, 2016 USD ($)	Jun. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Apr. 20, 2016 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			$ 0	$ 828	$ 0	$ 22,359
Sale of oil and gas properties	$ 7,000				24,832	$ 271,891
Required purchase price of the non-producing assets if agreement not reached					$ 5,000
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 (Bcfe) | Mcfe									227
Estimated proved reserves attributable to Sold Assets (percent of total)									57.00%
Gain on sale of oil and gas properties		$ 22,400
Woodford Shale assets (East Hoss Assets)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds from sale of a majority of interests							$ 18,000