Annual report pursuant to Section 13 and 15(d)

Selected Quarterly Financial Information (Details)

v3.8.0.1
Selected Quarterly Financial Information (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Selected Quarterly Financial Information [Abstract]                      
Revenues-oil and natural gas sales $ 17,156 $ 18,178 $ 20,425 $ 21,266 $ 15,326 $ 14,635 $ 18,847 $ 10,976 $ 77,025 $ 59,784 $ 80,445
Total operating costs and expenses 14,413 14,454 15,068 13,055 14,249 10,919 14,232 24,509 56,990 63,909 182,459
Operating income (loss) 2,495 3,721 5,587 8,148 819 3,690 4,615 (13,515) 19,951 (4,391) (103,106)
Income (loss) from continuing operations 3,534 (148) 2,451 4,435 (3,355) 1,016 (498) (15,430) 10,272 (18,267) (120,554)
Loss from discontinued operations (103) (174) (168) (176) (286) (15,783) (20) 7,806 (621) (8,283) (38,102)
Net income (loss) $ 3,431 $ (322) $ 2,283 $ 4,259 $ (3,641) $ (14,767) $ (518) $ (7,624) $ 9,651 $ (26,550) $ (158,656)
Basic net income (loss) per share $ 0.060 $ (0.010) $ 0.040 $ 0.070 $ (0.060) $ (0.250) $ (0.010) $ (0.130) $ 0.16 $ (0.45) $ (2.72)
Diluted net income (loss) per share $ 0.060 $ (0.010) $ 0.040 $ 0.070 $ (0.060) $ (0.250) $ (0.010) $ (0.130) $ 0.16 $ (0.45) $ (2.72)