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Stock-Based Compensation - Weighted Average Assumptions Used to Determine Fair Value of Option Grants (Detail)
12 Months Ended
Dec. 31, 2012
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Dividend yield 1.25%
Expected life 6 years
6 month 0.14%
1 year 0.18%
3 year 0.41%
5 year 0.84%
10 year 1.94%
Near term [Member]  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Volatility 37.00%
Long term [Member]  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Volatility 46.00%