XML 103 R86.htm IDEA: XBRL DOCUMENT v3.4.0.3
Share-based Compensation - Assumptions used to Estimate Fair Value of Stock Option Granted (Detail) - $ / shares
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Employee Stock Options 2013 Plan [Member]    
Share based Compensation Arrangement Assumptions Used to Estimate Fair Values of Share Options Granted [Line Items]    
Stock Price $ 24.01  
Risk-free rate 1.80%  
Expected volatility 36.98%  
Expected annual dividend yield 1.63%  
Expected term 6 years  
Employee Stock Options 2010 Plan [Member]    
Share based Compensation Arrangement Assumptions Used to Estimate Fair Values of Share Options Granted [Line Items]    
Stock Price   $ 23.36
Risk-free rate   1.68%
Expected volatility   36.56%
Expected annual dividend yield   1.71%
Expected term   6 years