Quarterly Consolidated Financial Data - Unaudited (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]                      
Revenues $ 22,608 $ 28,386 $ 21,928 $ 34,372 $ 61,448 $ 41,746 $ 35,897 $ 32,327      
Income (loss) from operations (149,272) [1] (180,272) [1] (107,462) [1] 8,172 [1] 37,063 20,413 12,539 8,497 $ (428,834) $ 78,512 $ 18,764
Income (loss) before provision for income taxes (157,525) (188,201) (114,395) 614 30,290 13,425 5,627 1,611      
Net income (loss) (157,525) (188,201) (114,395) 614 30,290 13,425 5,627 1,611 (459,507) 50,953 49,342
Dividend on preferred stock 3,618 3,618 3,619 3,618 3,619 3,618 3,611 3,576      
NET INCOME (LOSS) ATTRIBUTABLE TO COMMON STOCKHOLDERS $ (161,143) $ (191,819) $ (118,014) $ (3,004) $ 26,671 $ 9,807 $ 2,016 $ (1,965) $ (473,980) $ 36,529 $ 39,964
Basic (in dollars per share) $ (2.07) $ (2.47) $ (1.52) $ (0.04) $ 0.35 $ 0.16 $ 0.03 $ (0.03) $ (6.11) $ 0.58 $ 0.66
Diluted (in dollars per share) $ (2.07) $ (2.47) $ (1.52) $ (0.04) $ 0.34 $ 0.15 $ 0.03 $ (0.03) $ (6.11) $ 0.55 $ 0.63
Basic (shares) 77,685,049 77,628,120 77,611,167 77,114,826 75,994,979 60,006,903 58,702,982 58,204,532 77,511,677 63,270,733 60,220,115
Diluted (shares) 77,685,049 77,628,120 77,611,167 77,114,826 78,577,762 63,399,446 61,922,874 58,204,532 77,511,677 66,492,589 63,618,401
[1] Income (loss) from operations for the second, third and fourth quarters of 2015 includes impairment of oil and natural gas properties of $100.2 million, $182.0 million and $144.8 million, respectively.