Loss Per Share - Schedule of Loss per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]
Basic loss per share, Net Loss	$ (49,431)	$ (40,360)
Effect of dilutive incentive-based awards, Net Loss
Diluted loss per share, Net Loss	$ (49,431)	$ (40,360)
Basic loss per share, Shares	88,415	82,768
Effect of dilutive incentive-based awards, Shares
Diluted loss per share, Shares	88,415	82,768
Basic loss per share, Per Share Amount	$ (0.56)	$ (0.49)
Diluted loss per share, Per Share Amount	$ (0.56)	$ (0.49)