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Share-based Compensation Plans - Schedule of Share-based Payment Award, Valuation Assumptions (Detail) (USD $)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Expected volatility 32.10% 50.90% 49.60%
Expected volatility 50.80% 51.80% 49.90%
Expected term 5 years 4 years 6 months 4 years 6 months 29 days
Dividend rate         
Weighted average fair value of options granted during the year $ 10.83 $ 16.99 $ 14.21
Minimum [Member]
     
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Risk free interest rate 0.58% 0.76% 0.90%
Maximum [Member]
     
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Risk free interest rate 1.52% 0.84% 2.26%