Stock-Based Compensation Plans - Assumptions Used for the Black-Scholes Option-Pricing Model to Determine the Per Share Weighted Average Fair Value for Options Granted (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Expected life (years)	7 years	5 years	9 years 10 months 24 days
Risk-free interest rate	1.90%	1.70%	1.90%
Expected volatility	56.70%	35.50%	44.30%
Expected dividend yield	1.10%	1.00%	1.20%