Acquisitions and Divestitures - Acquisition (Fleetwood Joint Venture) (Details) a in Thousands, $ in Thousands	1 Months Ended
	Jun. 30, 2014 USD ($) a mi²	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Cash funding for future drilling, completion and lease acquisition costs, outstanding		$ 0	$ 4,409
Fleetwood Joint Venture | Louisiana
Business Acquisition [Line Items]
Purchase price	$ 24,000
Average working interest in leasehold position	37.00%
Acres acquired in leasehold position | a	30
Square miles of proprietary 3D survey | mi²	200
Cash portion of acquisition	$ 10,000
Cash funding for future drilling	$ 14,000
Cash funding for future drilling, completion and lease acquisition costs, outstanding			$ 4,400