Net Income (or Loss) and Number of Shares Used to Compute Basic and Diluted Earnings per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Loss Per Share [Line Items]
Net income (loss)-basic	$ 15,323	$ (39,774)	$ (10,657)	$ (101,932)
Gain on warrant derivative liability	(1,416)	(12,983)	(2,381)	(18,826)
Gain on exchangeable senior notes derivative liability	(200)
Exchangeable senior notes interest	1,960
Net income (loss)-diluted	$ 15,667	$ (52,757)	$ (13,038)	$ (120,758)
Net earnings (loss) per share-basic	$ 0.09	$ (0.26)	$ (0.06)	$ (0.68)
Weighted average shares outstanding-basic	172,886	150,694	172,879	150,562
Effect of dilutive warrants	963	6,349	997	6,505
Effect of dilutive exchangeable senior notes if converted	31,526
Weighted average shares outstanding-diluted	207,674	157,043	173,876	157,067
Net income (or loss) per share-diluted	$ 0.08	$ (0.34)	$ (0.07)	$ (0.77)
Stock Options
Earnings Loss Per Share [Line Items]
Effect of dilutive share based compensation	277
Restricted Stock
Earnings Loss Per Share [Line Items]
Effect of dilutive share based compensation	2,022

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Amount of increase (decrease) to net income used for calculating diluted earnings per share (EPS), resulting from the assumed exercise of dilutive convertible securities excluding adjustments related to ESOP convertible preferred stock, stock options, and restrictive stock units.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Aggregate gain on all derivative instruments recognized in earnings during the period, before tax effects.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of call options and warrants using the treasury stock method.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible debt securities using the if-converted method.

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Net Income or Loss Available to Common Stockholders plus adjustments resulting from the assumption that dilutive convertible securities were converted, options or warrants were exercised, or that other shares were issued upon the satisfaction of certain conditions.

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