Components of Calculation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Earnings Per Share [Abstract]
Net income (loss)	$ 19,225		$ (16,383)
Less: Preferred stock dividends	(1,722)		(1,725)
Dilutive Securities, Effect on Basic Earnings Per Share, Dilutive Convertible Securities	1,722		0
Loss attributable to common shareholders - Basic and Diluted	17,503		(18,108)
Net Income (Loss) Available to Common Stockholders, Diluted	$ 19,225		$ (18,108)
Weighted-average shares - Basic	65,611,000		55,341,000
Effect of dilutive securities	20,133,000	[1]	0	[1]
Weighted-average shares - Diluted	85,744,000		55,341,000
Preferred stock dividend rate	6.00%		6.00%
Potentially dilutive securities with the effect of being anti-dilutive excluded from the calculation of diluted earnings per common share (less than 0.1 million for the 3 months ended March 31, 2012)			19,200,000

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