Assumptions Used in Black-Scholes Pricing Model (Detail) - Stock Option Awards	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term of options in years	6 years 3 months 18 days	6 years 3 months 18 days	6 years 3 months 18 days
Expected volatility, minimum	33.20%	33.70%	37.40%
Expected volatility, maximum	33.40%	35.50%	37.80%
Risk-free interest rate, minimum	1.70%	2.70%	1.90%
Risk-free interest rate, maximum	2.50%	2.90%	2.30%
Expected dividend yield	0.00%	0.00%	0.00%