Stockholders' Equity - Weighted Average Assumptions Used for the Fair Value of Stock Options Granted Estimated at Grant Date Using Black-Scholes Option Pricing Model (Detail) (Stock Options, USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)			4 years 4 months 24 days	4 years 4 months 24 days
Expected volatility	0.00%	[1]	60.60%	63.30%
Risk-free interest rate	0.00%	[1]	1.70%	1.90%
Expected dividends	0.00%	[1]	0.00%	0.00%
Weighted average fair value at grant date (usd per share)	$ 0.00	[1]	$ 10.87	$ 9.08

[1] There were no stock options granted in 2012.