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Stock-Based Compensation - Fair Value of Date of Grant Using Black Scholes Option Pricing Model (Detail) (Stock Plans [Member])
9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Stock Plans [Member]
   
Share Based Payment Award Stock Options Valuation Assumptions [Line Items]    
Dividend yield 1.60% 1.70%
Risk-free interest rate 0.20% 0.20%
Expected volatility 51.00% 52.00%
Expected life (in years) 4 years 7 months 6 days 5 years 4 months 24 days