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Share-Based Compensation - Summary of Assumptions Utilized in the Black-Scholes Model for Stock Options Granted (Detail) (Stock Option [Member], USD $)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Stock Option [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted-average risk-free interest rate 0.27% 0.62% 1.34%
Expected term of option in years 3 years 2 months 16 days 4 years 3 months 3 years 11 months 1 day
Weighted-average volatility 34.10% 48.40% 58.50%
Dividend yield 9.10% 11.40% 8.90%
Weighted average grant date fair value per share $ 0.79 $ 0.87 $ 1.67