Estimated Fair Value of Options Granted using Black-Scholes Option-Pricing Model with Weighted-Average Assumptions (Detail)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Expected life (years)	5 years 11 months 5 days	5 years 6 months 18 days
Interest rate	1.80%	0.80%
Volatility	45.20%	50.00%
Dividend yield