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Stock-Based Compensation Plans - Assumptions Used to Determine Grant-Date Fair Value of Options (Detail) - Black-Scholes Model [Member]
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Dividend yield 1.09% 1.11% 0.96%
Expected life 5 years 5 years 5 years
Volatility 26.80% 25.60% 25.30%
Risk free interest rate 2.48% 2.74% 1.50%