Share-based Compensation - Schedule of Assumptions Used in Determining Fair Value of Stock Options Granted (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions And Methodology [Abstract]
Expected term (in years)	4 years 6 months	4 years 6 months	5 years
Expected volatility, minimum	30.60%	31.10%	31.70%
Expected volatility, maximum	32.30%	31.60%	34.50%
Risk free interest rate, minimum	1.07%	1.37%	1.52%
Risk free interest rate, maximum	1.92%	1.54%	1.70%
Weighted average grant date fair value	$ 11.79	$ 9.49	$ 10.45