Earnings (Loss) Per Share - Schedule of Net Loss Attributable to Stockholders, Weighted Average Shares Outstanding and Loss Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Earnings Per Share [Line Items]
Net loss attributable to common stockholders													$ (28,081)
Net loss	42,591	18,314	76,041	16,442	(13,401)	66,289	33,349	(6,847)	153,388		79,390		(29,695)
Weighted average shares outstanding									92,513	[1]	92,241	[1]	92,000	[1]
Loss per share									$ 1.66	[1]	$ 0.86	[1]	$ (0.31)	[1]
Previously Reported [Member]
Earnings Per Share [Line Items]
Net loss													$ (29,695)
Weighted average shares outstanding													48,395
Loss per share													$ (0.61)

[1] 2010 restated (see Note 11).