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Stock-Based Compensation Plans - Grant Date Fair Value Weighted-Average Assumptions - Options (Detail) - Black-Scholes Option-Pricing Model [Member] - Stock Option [Member]
3 Months Ended
Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Expected life (years) 5 years 7 months 6 days
Risk-free interest rate 2.70%
Expected volatility 26.40%
Expected dividend yield 0.00%