Earnings Per Share - Weighted-Average Shares of Common Stock Outstanding Used in Calculation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]
Net income (loss) from continuing operations	$ 21,531	$ (53,668)	$ (36,747)	$ (131,153)
Net income from discontinued operations		$ 969		$ 2,349
Basic weighted-average shares outstanding	127,885	121,689	127,555	118,159
Dilutive impact of stock options and restricted shares	1,195
Dilutive impact of common stock warrants	7,832
Diluted weighted-average shares outstanding	136,912	121,689	127,555	118,159
Earnings (loss) per share attributable to continuing operations:
Basic	$ 0.17	$ (0.44)	$ (0.29)	$ (1.11)
Diluted	$ 0.16	$ (0.44)	$ (0.29)	$ (1.11)
Earnings per share attributable to discontinued operations:
Basic and diluted		$ 0.01		$ 0.02