Equity - Common Stock (Details) shares in Thousands		1 Months Ended
	May 18, 2016 shares	Dec. 31, 2017 shares	Dec. 31, 2016 shares	May 17, 2016 shares
Class of Stock [Line Items]
Common stock, shares outstanding		25,521	21,197
Common Stock
Class of Stock [Line Items]
Reverse stock split, conversion ratio	0.25
Common stock, shares outstanding	17,600			70,500
Austin Chalk Acreage
Class of Stock [Line Items]
Common shares issued in connection with acquisition		2,000