Earnings (Loss) Per Share - Computation of Basic Diluted Earnings Per Share (Detail) - 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 |
|
| Earnings Per Share Reconciliation [Abstract] | |||||||||||
| Net income (loss) | $ 5,447 | $ (32,970) | $ (26,288) | $ (30,445) | $ (17,651) | $ 9,553 | $ (16,799) | $ (54,723) | $ (84,256) | $ (79,620) | $ 130,083 |
| Basic weighted-average common shares (in shares) | 96,806,885 | 95,760,762 | 95,687,940 | ||||||||
| Add: Effect of dilutive securities (in shares) | 0 | 0 | 1,157,724 | ||||||||
| Diluted weighted-average common shares (in shares) | 96,806,885 | 95,760,762 | 96,845,664 | ||||||||
| Net income (loss) per common share (basic) (in dollars per share) | $ 0.06 | $ (0.34) | $ (0.27) | $ (0.32) | $ (0.18) | $ 0.10 | $ (0.18) | $ (0.57) | $ (0.87) | $ (0.83) | $ 1.36 |
| Net income (loss) per common share (diluted) (in dollars per share) | $ 0.06 | $ (0.34) | $ (0.27) | $ (0.32) | $ (0.18) | $ 0.10 | $ (0.18) | $ (0.57) | $ (0.87) | $ (0.83) | $ 1.34 |