|
Supplementary Data - Selected Quarterly Financial Data (Detail) (USD $)
In Thousands, except Per Share data, unless otherwise specified |
3 Months Ended | 12 Months Ended | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Dec. 31, 2012
|
Sep. 30, 2012
|
Jun. 30, 2012
|
Mar. 31, 2012
|
Dec. 31, 2011
|
Sep. 30, 2011
|
Jun. 30, 2011
|
Mar. 31, 2011
|
Dec. 31, 2010
|
Sep. 30, 2010
|
Jun. 30, 2010
|
Mar. 31, 2010
|
Dec. 31, 2012
|
Dec. 31, 2011
|
Dec. 31, 2010
|
|
| Schedule Of Quarterly Financial Data [Line Items] | |||||||||||||||
| Net revenue | $ 35,309 | $ 33,038 | $ 29,927 | $ 30,618 | $ 31,123 | $ 27,958 | $ 29,123 | $ 20,183 | $ 16,290 | $ 14,916 | $ 13,155 | $ 13,220 | $ 128,892 | $ 108,387 | $ 57,581 |
| Net operating expenses | (36,777) | (31,340) | (26,095) | (23,879) | (42,339) | (19,092) | (18,170) | (17,930) | (15,493) | (12,350) | (10,191) | (12,368) | 118,091 | 97,531 | 50,402 |
| Interest expense, net | (926) | (1,544) | (1,380) | (887) | (1,010) | (1,016) | (863) | (513) | (558) | (615) | (550) | (466) | 4,737 | 3,402 | 2,189 |
| Loss on equity investment | (108) | (108) | |||||||||||||
| Realized gain (loss) on commodity derivatives | (408) | 423 | 361 | (484) | 1,720 | 1,392 | 66 | 197 | 2,171 | 1,615 | 1,768 | 230 | (108) | 3,375 | 5,784 |
| Unrealized gain (loss) on commodity derivatives | 1,292 | (4,185) | 9,439 | (2,672) | (4,168) | 1,739 | 2,231 | (149) | (2,094) | (312) | (1,901) | 5,095 | (3,874) | 347 | (788) |
| (Loss) gain on sale of oil and gas properties | (243) | 3 | 488 | 248 | |||||||||||
| (Loss) income before income tax (benefit) | (1,618) | (3,608) | 12,252 | 2,696 | (14,917) | 10,981 | 12,390 | 2,276 | 316 | 3,254 | 2,281 | 5,711 | 9,722 | 10,730 | 11,562 |
| Income tax (benefit) provision | (781) | (1,253) | 4,390 | 982 | (5,632) | 3,908 | 4,400 | 812 | 55 | 1,167 | 730 | 2,148 | (3,338) | (3,488) | (4,100) |
| Net (loss) income | $ (837) | $ (2,355) | $ 7,862 | $ 1,714 | $ (9,285) | $ 7,073 | $ 7,990 | $ 1,464 | $ 261 | $ 2,087 | $ 1,551 | $ 3,563 | $ 6,384 | $ 7,242 | $ 7,462 |
| Basic net (loss) income applicable to common stockholders per common share | $ (0.02) | $ (0.07) | $ 0.23 | $ 0.05 | $ (0.30) | $ 0.25 | $ 0.28 | $ 0.05 | $ 0.01 | $ 0.10 | $ 0.07 | $ 0.17 | $ 0.18 | $ 0.25 | $ 0.34 |
| Diluted net (loss) income applicable to common stockholders per common share | $ (0.02) | $ (0.07) | $ 0.23 | $ 0.05 | $ (0.30) | $ 0.25 | $ 0.28 | $ 0.05 | $ 0.01 | $ 0.10 | $ 0.07 | $ 0.17 | $ 0.18 | $ 0.25 | $ 0.34 |