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Benefit Plans - Schedule of Weighted-Average Assumptions Used to Determine Fair Value of Option Granted (Detail)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]      
Expected term (in years) 5 years 5 years 5 years
Expected volatility 50.30% 52.10% 51.60%
Expected dividend yields 3.30% 3.20% 3.40%
Risk-free interest rates 0.80% 0.80% 2.00%