Earnings (Loss) Per Share - Reconciliation of Numerators and Denominators of Basic and Diluted Earnings Per Share Computations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Basic earnings (loss) per share
Net income (loss)	$ (31,008)	$ 17,377
Less: Net income allocated to unvested participating securities	0	(133)
Net income (loss) available to common stockholders (numerator)	(31,008)	17,244
Weighted-average common shares outstanding (denominator) (in shares)	37,718	37,429
Basic earnings (loss) per share (in usd per share)	$ (0.82)	$ 0.46
Diluted earnings (loss) per share
Net income (loss)	(31,008)	17,377
Less: Net income allocated to unvested participating securities	0	(131)
Net income (loss) available to common stockholders (numerator)	$ (31,008)	$ 17,246
Weighted-average common shares outstanding (in shares)	37,718	37,429
Add: Effect of dilutive stock options and convertible notes (in shares)	0	576
Diluted weighted-average common shares outstanding (denominator) (in shares)	37,718	38,005
Diluted earnings (loss) per share (in usd per share)	$ (0.82)	$ 0.45