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Stock-Based Compensation - Significant Assumptions used in Determining Fair Value of Options Granted (Detail)
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]    
Dividend yield 0.89% 1.08%
Expected life (in months) 84 months 84 months
Risk-free rate of interest 1.50% 2.63%
Volatility 20.96% 21.38%