Earnings per Share (Reconciliation of Basic and Diluted Earnings (Loss) per Common Share (Detail) (USD $)
In Thousands, except Share data, unless otherwise specified
 3 Months Ended 12 Months Ended
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Earnings Per Share [Abstract]                      
Net income (loss) available to common shareholders $ (184,000) $ (35,600) $ (42,800) $ (90,600) $ (20,000) $ (9,800) $ (43,000) $ (38,400) $ (352,955) $ (111,206) $ (173,829)
Weighted average common stock outstanding                 52,835,000 52,583,000 52,365,000
Weighted average restricted stock                 458,000 541,000 485,000
Weighted average common shares outstanding - basic 53,331,000 53,328,000 53,323,000 53,188,000 53,172,000 53,172,000 53,172,000 52,976,000 53,293,000 53,124,000 52,850,000
Dilutive shares from stock options                 0 0 0
Weighted average common shares outstanding - diluted 53,331,000 53,328,000 53,323,000 53,188,000 53,172,000 53,172,000 53,172,000 52,976,000 53,293,000 53,124,000 52,850,000
Basic loss per share $ (3.45) $ (0.67) $ (0.80) $ (1.70) $ (0.38) $ (0.18) $ (0.81) $ (0.72) $ (6.62) $ (2.09) $ (3.29)
Diluted loss per share $ (3.45) $ (0.67) $ (0.80) $ (1.70) $ (0.38) $ (0.18) $ (0.81) $ (0.72) $ (6.62) $ (2.09) $ (3.29)