Annual report pursuant to Section 13 and 15(d)

STOCK-BASED COMPENSATION - Fair Value of Employee Stock Options Granted as Determined by Black-Scholes Valuation Model Assumptions (Detail)

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STOCK-BASED COMPENSATION - Fair Value of Employee Stock Options Granted as Determined by Black-Scholes Valuation Model Assumptions (Detail) - Nonqualified Stock Options - $ / shares
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected dividend yield 2.63% 2.56% 2.75%
Risk-free interest rate 2.07% 2.40% 1.38%
Expected life in years 7 years 6 months 7 years 6 months 7 years 6 months
Expected volatility 20.61% 24.26% 24.85%
Weighted average fair value of options granted $ 18.07 $ 20.48 $ 15.50