CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Other property and equipment, accumulated depreciation	$ 2,701	$ 2,546
Oil and gas properties held for sale, accumulated depreciation, depletion and amortization	$ 0	$ 2,583
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	225,000,000	225,000,000
Common stock, shares issued (in shares)	20,558,591	20,453,549
Common stock, shares outstanding (in shares)	20,558,591	20,453,549