Earnings (Loss) Per Share - Reconciliation of Numerators and Denominators of Basic and Diluted Earnings Per Share Computations (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Basic earnings (loss) per share
Net income (loss)	$ (38,119)	$ (12,929)	$ (69,127)	$ 4,448
Less: Net income allocated to unvested participating securities	0	0	0	(34)
Net income (loss) available to common stockholders (numerator)	$ (38,119)	$ (12,929)	$ (69,127)	$ 4,414
Weighted-average common shares outstanding (denominator) (in shares)	37,759	37,673	37,739	37,552
Basic earnings (loss) per share (in usd per share)	$ (1.01)	$ (0.34)	$ (1.83)	$ 0.12
Diluted earnings (loss) per share
Net income (loss)	$ (38,119)	$ (12,929)	$ (69,127)	$ 4,448
Less: Net income allocated to unvested participating securities	0	0	0	(33)
Net income (loss) available to common stockholders (numerator)	$ (38,119)	$ (12,929)	$ (69,127)	$ 4,415
Weighted-average common shares outstanding (in shares)	37,759	37,673	37,739	37,552
Add: Effect of dilutive stock options and convertible notes (in shares)	0	0	0	522
Diluted weighted-average common shares outstanding (denominator) (in shares)	37,759	37,673	37,739	38,074
Diluted earnings (loss) per share (in usd per share)	$ (1.01)	$ (0.34)	$ (1.83)	$ 0.12