Calculation of Basic and Diluted Net Income (Loss) per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
BASIC EPS:
Net income (loss)	$ (70,503)	$ 9,125
Adjust for (income) loss attributed to holders of non-vested restricted stock	681	(86)
Income attributed to common stockholders	$ (69,822)	$ 9,039
Weighted average number of common shares outstanding, excluding non-vested shares of restricted stock	145,770	144,983
Basic net income (loss) per common share	$ (0.48)	$ 0.06
DILUTED EPS:
Income (loss) attributed to common stockholders	$ (69,822)	$ 9,039
Weighted average number of common shares outstanding, excluding non-vested shares of restricted stock	145,770	144,983
Add dilutive effect of potential common shares		762
Weighted average number of diluted common shares outstanding	145,770	145,745
Diluted net income (loss) per common share	$ (0.48)	$ 0.06
Potentially dilutive securities excluded as anti-dilutive	7,740	5,569