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Share-Based Compensation Plans - Fair Value of Options as of Grant Dates Using Weighted Average Assumptions (Detail) (USD $)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]      
Weighted average fair value $ 8.20   $ 6.98
Expected volatility 39.86%   41.85%
Expected life (years) 4 years 3 months   6 years 6 months
Risk-free interest rate 0.65%   2.58%
Dividend yield 0.00% 0.00% 0.00%