Components of Calculation of Basic and Diluted Earnings Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Net loss		$ (1,582,961)	$ (409,592)	$ (143,070)
Less: Preferred stock dividends	[1]	(22,789)	(17,148)	(6,900)
Induced conversion of preferred stock		0	(4,256)	0
Net loss attributable to common shareholders – basic and diluted		$ (1,605,750)	$ (430,996)	$ (149,970)
Weighted-average shares – basic		73,639	68,887	62,335
Effect of dilutive securities	[2]	0	0	0
Weighted-average shares – diluted		73,639	68,887	62,335
Potentially dilutive securities with the effect of being anti-dilutive excluded from the calculation of diluted earnings per common share		30,200	26,600	19,800

[1] Preferred stock dividends were excluded from diluted earnings per share for the years ended December 31, 2015, 2014 and 2013, as the assumed conversion of the outstanding preferred stock would have been anti-dilutive.

[2] For 2015 and 2014, approximately 30.2 million and 26.6 million potentially dilutive securities, including the Series A and Series B Preferred Stock, stock options and restricted stock units had the effect of being anti-dilutive and were excluded from the calculation of diluted earnings per common share. For 2013, approximately and 19.8 million, respectively, potentially dilutive securities, including the Series A Preferred Stock, stock options and restricted stock units had the effect of being anti-dilutive and were excluded from the calculation of diluted earnings per common share.