Calculation of Basic and Diluted Net Loss per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
BASIC EPS:
Net loss	$ (85,866)	$ (18,975)	$ (156,369)	$ (9,850)
Adjust for loss attributed to holders of non-vested restricted stock	846	198	1,526	109
Loss attributed to other common stockholders	$ (85,020)	$ (18,777)	$ (154,843)	$ (9,741)
Weighted average number of common shares outstanding, excluding non-vested shares of restricted stock	145,944	145,300	145,857	145,142
Basic net loss per common share	$ (0.58)	$ (0.13)	$ (1.06)	$ (0.07)
DILUTED EPS:
Loss attributed to other common stockholders	$ (85,020)	$ (18,777)	$ (154,843)	$ (9,741)
Weighted average number of common shares outstanding, excluding non-vested shares of restricted stock	145,944	145,300	145,857	145,142
Weighted average number of diluted common shares outstanding	145,944	145,300	145,857	145,142
Diluted net loss per common share	$ (0.58)	$ (0.13)	$ (1.06)	$ (0.07)
Potentially dilutive securities excluded as anti-dilutive	9,370	8,208	9,370	8,208