Stock-Based Compensation (Detail) - Weighted Average Assumptions To Estimate The Fair Value Of Equity Awards (USD $)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Stock options [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free rate 0.93% 1.11% 1.44%
Expected volatility 61.00% 61.00% 59.00%
Expected term (in years) 6 years 1 month 5 days 6 years 0 months 0 days 6 years 4 months 30 days
Grant date fair value $ 7.39 $ 9.02 $ 7.81
Performance-based restricted stock units with a market condition [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free rate 0.59%    
Expected volatility 53.00%    
Grant date fair value $ 6.39