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Stock-Based Compensation Plans and Arrangements - Black-Scholes Model Assumptions for Calculating Stock Option and ESPP Fair Values (Detail) (USD $)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Employee Stock Option [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 0.65% 0.60% 1.57%
Expected volatility 31.00% 44.00% 54.00%
Expected dividend rate 3.35% 3.13% 2.58%
Expected life of the option 2 years 9 months 18 days 2 years 9 months 18 days 4 years 1 month 6 days
Weighted average fair value of options granted $ 3.11 $ 4.12 $ 5.18
Employee Stock Purchase Plan [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 0.15% 0.13% 0.27%
Expected volatility 29.00% 29.00% 42.00%
Expected dividend rate 3.51% 3.27% 1.87%
Expected life of the option 1 year 1 year 1 year
Weighted average fair value of options granted $ 2.95 $ 3.01 $ 3.63